diff --git a/packages/ERTP/package.json b/packages/ERTP/package.json
index f29190a597f..b319be6f27b 100644
--- a/packages/ERTP/package.json
+++ b/packages/ERTP/package.json
@@ -86,6 +86,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 90.62
+    "atLeast": 91.21
   }
 }
diff --git a/packages/ERTP/src/amountMath.js b/packages/ERTP/src/amountMath.js
index 314a5644a78..a6e362ba045 100644
--- a/packages/ERTP/src/amountMath.js
+++ b/packages/ERTP/src/amountMath.js
@@ -6,7 +6,10 @@ import { setMathHelpers } from './mathHelpers/setMathHelpers.js';
 import { copySetMathHelpers } from './mathHelpers/copySetMathHelpers.js';
 import { copyBagMathHelpers } from './mathHelpers/copyBagMathHelpers.js';
 
-/** @import {Amount, AssetKind, AmountValue, AssetKindForValue, AssetValueForKind, Brand, MathHelpers} from './types.js' */
+/**
+ * @import {CopyBag, CopySet} from '@endo/patterns';
+ * @import {Amount, AssetKind, AmountValue, AssetKindForValue, AssetValueForKind, Brand, CopyBagAmount, CopySetAmount, MathHelpers, NatAmount, NatValue, SetAmount, SetValue} from './types.js';
+ */
 
 const { quote: q, Fail } = assert;
 
@@ -76,26 +79,19 @@ const helpers = {
   copyBag: copyBagMathHelpers,
 };
 
-/**
- * @template {AmountValue} V
- * @type {(value: V) => AssetKindForValue<V>}
- */
+/** @type {(value: unknown) => 'nat' | 'set' | 'copySet' | 'copyBag'} } */
 const assertValueGetAssetKind = value => {
   const passStyle = passStyleOf(value);
   if (passStyle === 'bigint') {
-    // @ts-expect-error cast
     return 'nat';
   }
   if (passStyle === 'copyArray') {
-    // @ts-expect-error cast
     return 'set';
   }
   if (matches(value, M.set())) {
-    // @ts-expect-error cast
     return 'copySet';
   }
   if (matches(value, M.bag())) {
-    // @ts-expect-error cast
     return 'copyBag';
   }
   // TODO This isn't quite the right error message, in case valuePassStyle
@@ -113,7 +109,7 @@ const assertValueGetAssetKind = value => {
  *
  * Made available only for testing, but it is harmless for other uses.
  *
- * @template {AmountValue} V
+ * @template V
  * @param {V} value
  * @returns {MathHelpers<V>}
  */
@@ -198,29 +194,44 @@ const isGTE = (leftAmount, rightAmount, brand = undefined) => {
  * the abstract right to participate in a particular exchange.
  */
 const AmountMath = {
+  // TODO use overloading to handle when Brand has an AssetKind and when it doesn't.
+  // a AmountForValue utility could help DRY those cases.
   /**
    * Make an amount from a value by adding the brand.
    *
-   * @template {AssetKind} K
-   * @param {Brand<K>} brand
-   * @param {AssetValueForKind<K>} allegedValue
-   * @returns {Amount<K>}
+   * Does not verify that the Brand's AssetKind matches the value's.
+   *
+   * @template {Brand} B
+   * @template {NatValue | CopySet | CopyBag | SetValue} V
+   * @param {B} brand
+   * @param {V} allegedValue
+   * @returns {B extends Brand<'nat'>
+   *     ? NatAmount
+   *     : V extends NatValue
+   *       ? NatAmount
+   *       : V extends CopySet
+   *         ? CopySetAmount<V['payload'][0]>
+   *         : V extends CopyBag
+   *           ? CopyBagAmount<V['payload'][0][0]>
+   *           : V extends SetValue
+   *             ? SetAmount<V[0]>
+   *             : never}
    */
-  // allegedValue has a conditional expression for type widening, to prevent V being bound to a a literal like 1n
   make: (brand, allegedValue) => {
     assertRemotable(brand, 'brand');
     const h = assertValueGetHelpers(allegedValue);
     const value = h.doCoerce(allegedValue);
+    // @ts-expect-error cast
     return harden({ brand, value });
   },
   /**
    * Make sure this amount is valid enough, and return a corresponding valid
    * amount if so.
    *
-   * @template {AssetKind} K
-   * @param {Brand<K>} brand
-   * @param {Amount<K>} allegedAmount
-   * @returns {Amount<K>}
+   * @template {Amount} A
+   * @param {Brand} brand
+   * @param {A} allegedAmount
+   * @returns {A}
    */
   coerce: (brand, allegedAmount) => {
     assertRemotable(brand, 'brand');
@@ -229,15 +240,16 @@ const AmountMath = {
     brand === allegedBrand ||
       Fail`The brand in the allegedAmount ${allegedAmount} in 'coerce' didn't match the specified brand ${brand}.`;
     // Will throw on inappropriate value
+    // @ts-expect-error cast
     return AmountMath.make(brand, allegedValue);
   },
   /**
    * Extract and return the value.
    *
-   * @template {AssetKind} K
-   * @param {Brand<K>} brand
-   * @param {Amount<K>} amount
-   * @returns {AssetValueForKind<K>}
+   * @template {Amount} A
+   * @param {Brand} brand
+   * @param {A} amount
+   * @returns {A['value']}
    */
   getValue: (brand, amount) => AmountMath.coerce(brand, amount).value,
   /**
@@ -246,29 +258,29 @@ const AmountMath = {
    *
    * @type {{
    *   (brand: Brand): Amount<'nat'>;
-   *   <K extends AssetKind>(brand: Brand, assetKind: K): Amount<K>;
+   *   <K extends AssetKind>(brand: Brand<K>, assetKind: K): Amount<K>;
    * }}
    */
   makeEmpty: (brand, assetKind = /** @type {const} */ ('nat')) => {
     assertRemotable(brand, 'brand');
     assertAssetKind(assetKind);
     const value = helpers[assetKind].doMakeEmpty();
+    // @ts-expect-error XXX narrowing from function overload
     return harden({ brand, value });
   },
   /**
    * Return the amount representing an empty amount, using another amount as the
    * template for the brand and assetKind.
    *
-   * @template {AssetKind} K
-   * @param {Amount<K>} amount
-   * @returns {Amount<K>}
+   * @template {Amount} A
+   * @param {A} amount
+   * @returns {A}
    */
   makeEmptyFromAmount: amount => {
     assertRecord(amount, 'amount');
     const { brand, value } = amount;
-    // @ts-expect-error cast
     const assetKind = assertValueGetAssetKind(value);
-    // @ts-expect-error cast (ignore b/c erroring in CI but not my IDE)
+    // @ts-expect-error different subtype
     return AmountMath.makeEmpty(brand, assetKind);
   },
   /**
@@ -291,10 +303,10 @@ const AmountMath = {
    * Returns true if the leftAmount equals the rightAmount. We assume that if
    * isGTE is true in both directions, isEqual is also true
    *
-   * @template {AssetKind} K
-   * @param {Amount<K>} leftAmount
-   * @param {Amount<K>} rightAmount
-   * @param {Brand<K>} [brand]
+   * @template {Amount} A
+   * @param {A} leftAmount
+   * @param {A} rightAmount
+   * @param {Brand} [brand]
    * @returns {boolean}
    */
   isEqual: (leftAmount, rightAmount, brand = undefined) => {
@@ -308,15 +320,16 @@ const AmountMath = {
    * amount, it usually means including all of the elements from both left and
    * right.
    *
-   * @template {AssetKind} K
-   * @param {Amount<K>} leftAmount
-   * @param {Amount<K>} rightAmount
-   * @param {Brand<K>} [brand]
-   * @returns {Amount<K>}
+   * @template {Amount} A
+   * @param {A} leftAmount
+   * @param {A} rightAmount
+   * @param {Brand} [brand]
+   * @returns {A}
    */
   add: (leftAmount, rightAmount, brand = undefined) => {
     const h = checkLRAndGetHelpers(leftAmount, rightAmount, brand);
     const value = h.doAdd(...coerceLR(h, leftAmount, rightAmount));
+    // @ts-expect-error different subtype
     return harden({ brand: leftAmount.brand, value });
   },
   /**
@@ -326,25 +339,27 @@ const AmountMath = {
    * error. Because the left amount must include the right amount, this is NOT
    * equivalent to set subtraction.
    *
-   * @template {AssetKind} K
-   * @param {Amount<K>} leftAmount
-   * @param {Amount<K>} rightAmount
-   * @param {Brand<K>} [brand]
-   * @returns {Amount<K>}
+   * @template {Amount} L
+   * @template {Amount} R
+   * @param {L} leftAmount
+   * @param {R} rightAmount
+   * @param {Brand} [brand]
+   * @returns {L extends R ? L : never}
    */
   subtract: (leftAmount, rightAmount, brand = undefined) => {
     const h = checkLRAndGetHelpers(leftAmount, rightAmount, brand);
     const value = h.doSubtract(...coerceLR(h, leftAmount, rightAmount));
+    // @ts-expect-error different subtype
     return harden({ brand: leftAmount.brand, value });
   },
   /**
    * Returns the min value between x and y using isGTE
    *
-   * @template {AssetKind} K
-   * @param {Amount<K>} x
-   * @param {Amount<K>} y
-   * @param {Brand<K>} [brand]
-   * @returns {Amount<K>}
+   * @template {Amount} A
+   * @param {A} x
+   * @param {A} y
+   * @param {Brand} [brand]
+   * @returns {A}
    */
   min: (x, y, brand = undefined) =>
     // eslint-disable-next-line no-nested-ternary
@@ -356,11 +371,11 @@ const AmountMath = {
   /**
    * Returns the max value between x and y using isGTE
    *
-   * @template {AssetKind} K
-   * @param {Amount<K>} x
-   * @param {Amount<K>} y
-   * @param {Brand<K>} [brand]
-   * @returns {Amount<K>}
+   * @template {Amount} A
+   * @param {A} x
+   * @param {A} y
+   * @param {Brand} [brand]
+   * @returns {A}
    */
   max: (x, y, brand = undefined) =>
     // eslint-disable-next-line no-nested-ternary
@@ -376,7 +391,6 @@ harden(AmountMath);
 const getAssetKind = amount => {
   assertRecord(amount, 'amount');
   const { value } = amount;
-  // @ts-expect-error cast (ignore b/c erroring in CI but not my IDE)
   return assertValueGetAssetKind(value);
 };
 harden(getAssetKind);
diff --git a/packages/ERTP/src/issuerKit.js b/packages/ERTP/src/issuerKit.js
index 107e245f842..0a4ee145b7a 100644
--- a/packages/ERTP/src/issuerKit.js
+++ b/packages/ERTP/src/issuerKit.js
@@ -325,7 +325,7 @@ harden(prepareIssuerKit);
  *   anything else is corrupted by that corrupted state. See
  *   https://github.com/Agoric/agoric-sdk/issues/3434
  * @param {IssuerOptionsRecord} [options]
- * @returns {IssuerKit<K>}
+ * @returns {IssuerKit<K, any>}
  */
 export const makeIssuerKit = (
   name,
diff --git a/packages/ERTP/src/legacy-payment-helpers.js b/packages/ERTP/src/legacy-payment-helpers.js
index af53e22a628..55dccaae538 100644
--- a/packages/ERTP/src/legacy-payment-helpers.js
+++ b/packages/ERTP/src/legacy-payment-helpers.js
@@ -5,7 +5,7 @@ import { E } from '@endo/far';
 import { AmountMath } from './amountMath.js';
 
 /**
- * @import {ERef} from '@endo/far');
+ * @import {ERef} from '@endo/far';
  * @import {Amount, AssetKind, AmountValue, AssetKindForValue, Payment, Brand, Purse} from './types.js'
  */
 
@@ -26,11 +26,11 @@ const { Fail } = assert;
  */
 
 /**
- * @template {AssetKind} K
- * @param {ERef<Purse<K>>} recoveryPurse
- * @param {ERef<Payment<K>>} srcPaymentP
+ * @template {Payment} P
+ * @param {ERef<Purse>} recoveryPurse
+ * @param {ERef<P>} srcPaymentP
  * @param {Pattern} [optAmountShape]
- * @returns {Promise<Payment<K>>}
+ * @returns {Promise<P>}
  */
 export const claim = async (
   recoveryPurse,
@@ -38,6 +38,7 @@ export const claim = async (
   optAmountShape = undefined,
 ) => {
   const srcPayment = await srcPaymentP;
+  // @ts-expect-error XXX could be instantiated with a different subtype
   return E.when(E(recoveryPurse).deposit(srcPayment, optAmountShape), amount =>
     E(recoveryPurse).withdraw(amount),
   );
diff --git a/packages/ERTP/src/paymentLedger.js b/packages/ERTP/src/paymentLedger.js
index 5b9645f7e06..33ae4c658f0 100644
--- a/packages/ERTP/src/paymentLedger.js
+++ b/packages/ERTP/src/paymentLedger.js
@@ -15,6 +15,7 @@ import { BrandI, makeIssuerInterfaces } from './typeGuards.js';
 /**
  * @import {Amount, AssetKind, DisplayInfo, PaymentLedger, Payment, Brand, RecoverySetsOption, Purse, Issuer, Mint} from './types.js'
  * @import {ShutdownWithFailure} from '@agoric/swingset-vat'
+ * @import {Key} from '@endo/patterns';
  */
 
 const { details: X, quote: q, Fail } = assert;
@@ -93,11 +94,7 @@ export const preparePaymentLedger = (
   optShutdownWithFailure = undefined,
 ) => {
   /** @type {Brand<K>} */
-  // Should be
-  // at-ts-expect-error XXX callWhen
-  // but ran into the usual disagreement between local lint and CI
-
-  // @ts-expect-error
+  // @ts-expect-error XXX callWhen
   const brand = issuerZone.exo(`${name} brand`, BrandI, {
     isMyIssuer(allegedIssuer) {
       // BrandI delays calling this method until `allegedIssuer` is a Remotable
@@ -299,7 +296,7 @@ export const preparePaymentLedger = (
   };
 
   /** @type {() => Purse<K>} */
-  // @ts-expect-error type parameter confusion
+  // @ts-expect-error XXX amount kinds
   const makeEmptyPurse = preparePurseKind(
     issuerZone,
     name,
@@ -315,11 +312,7 @@ export const preparePaymentLedger = (
   );
 
   /** @type {Issuer<K>} */
-  // Should be
-  // at-ts-expect-error cast due to callWhen discrepancy
-  // but ran into the usual disagreement between local lint and CI
-
-  // @ts-expect-error
+  // @ts-expect-error XXX callWhen
   const issuer = issuerZone.exo(`${name} issuer`, IssuerI, {
     getBrand() {
       return brand;
@@ -374,11 +367,6 @@ export const preparePaymentLedger = (
    * `makeIssuerKit` drops it on the floor, it can still be recovered in an
    * emergency upgrade.
    */
-  // Should be
-  // at-ts-expect-error checked cast
-  // but ran into the usual disagreement between local lint and IDE lint.
-  // Don't know yet about lint under CI.
-
   const mintRecoveryPurse = /** @type {Purse<K>} */ (
     issuerZone.makeOnce('mintRecoveryPurse', () => makeEmptyPurse())
   );
@@ -389,10 +377,6 @@ export const preparePaymentLedger = (
       return issuer;
     },
     mintPayment(newAmount) {
-      // Should be
-      // at-ts-expect-error checked cast
-      // but ran into the usual disagreement between local lint and CI
-
       newAmount = coerce(newAmount);
       mustMatch(newAmount, amountShape, 'minted amount');
       // `rawPayment` is not associated with any recovery set, and
diff --git a/packages/ERTP/src/transientNotifier.js b/packages/ERTP/src/transientNotifier.js
index a01eaeb28c1..a445a365e66 100644
--- a/packages/ERTP/src/transientNotifier.js
+++ b/packages/ERTP/src/transientNotifier.js
@@ -6,7 +6,7 @@ import { makeNotifierKit } from '@agoric/notifier';
 
 /**
  * @import {Purse} from './types.js';
- * @import {LatestTopic, NotifierRecord} from '@agoric/notifier');
+ * @import {NotifierRecord} from '@agoric/notifier';
  */
 
 // Note: Virtual for high cardinality, but *not* durable, and so
diff --git a/packages/ERTP/src/types.js b/packages/ERTP/src/types.js
index 91a97b288b1..d26934d942a 100644
--- a/packages/ERTP/src/types.js
+++ b/packages/ERTP/src/types.js
@@ -5,23 +5,45 @@ export {};
 
 /// <reference types="ses"/>
 /**
- * @import {ERef} from '@endo/far');
- * @import {CopySet, Key} from '@endo/patterns');
- * @import {LatestTopic, NotifierRecord} from '@agoric/notifier');
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ * @import {CopyBag, CopySet, Key} from '@endo/patterns';
+ * @import {LatestTopic, NotifierRecord} from '@agoric/notifier';
  */
 
+/** @typedef {{ brand: Brand<'nat'>; value: bigint }} NatAmount */
+/**
+ * @template {Key} K
+ * @typedef {{ brand: Brand<'set'>; value: K[] }} SetAmount
+ */
+/**
+ * @template {Key} K
+ * @typedef {{ brand: Brand<'copySet'>; value: CopySet<K> }} CopySetAmount
+ */
+/**
+ * @template {Key} K
+ * @typedef {{ brand: Brand<'copyBag'>; value: CopyBag<K> }} CopyBagAmount
+ */
+/** @typedef {{ brand: Brand<any>; value: any }} AnyAmount */
+
 /**
  * @template {AssetKind} [K=AssetKind]
- * @typedef {object} Amount Amounts are descriptions of digital assets,
- *   answering the questions "how much" and "of what kind". Amounts are values
- *   labeled with a brand. AmountMath executes the logic of how amounts are
- *   changed when digital assets are merged, separated, or otherwise
- *   manipulated. For example, a deposit of 2 bucks into a purse that already
- *   has 3 bucks gives a new purse balance of 5 bucks. An empty purse has 0
- *   bucks. AmountMath relies heavily on polymorphic MathHelpers, which
- *   manipulate the unbranded portion.
- * @property {Brand<K>} brand
- * @property {AssetValueForKind<K>} value
+ * @template {Key} [M=Key]
+ * @typedef {K extends 'nat'
+ *   ? NatAmount
+ *   : K extends 'set'
+ *     ? SetAmount<M>
+ *     : K extends 'copySet'
+ *       ? CopySetAmount<M>
+ *       : K extends 'copyBag'
+ *         ? CopyBagAmount<M>
+ *         : AnyAmount} Amount
+ *   Amounts are descriptions of digital assets, answering the questions "how
+ *   much" and "of what kind". Amounts are values labeled with a brand.
+ *   AmountMath executes the logic of how amounts are changed when digital
+ *   assets are merged, separated, or otherwise manipulated. For example, a
+ *   deposit of 2 bucks into a purse that already has 3 bucks gives a new purse
+ *   balance of 5 bucks. An empty purse has 0 bucks. AmountMath relies heavily
+ *   on polymorphic MathHelpers, which manipulate the unbranded portion.
  */
 
 /**
@@ -54,14 +76,15 @@ export {};
 
 /**
  * @template {AssetKind} K
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
  * @typedef {K extends 'nat'
  *   ? NatValue
  *   : K extends 'set'
- *     ? SetValue
+ *     ? SetValue<M>
  *     : K extends 'copySet'
- *       ? CopySet
+ *       ? CopySet<M>
  *       : K extends 'copyBag'
- *         ? import('@endo/patterns').CopyBag
+ *         ? CopyBag<M>
  *         : never} AssetValueForKind
  */
 
@@ -94,18 +117,11 @@ export {};
  *   or AssetKind.SET or AssetKind.COPY_SET (non-fungible)
  */
 
+// XXX hack around JSDoc union handling
 /**
- * @template {AssetKind} [K=AssetKind]
- * @typedef {object} Brand The brand identifies the kind of issuer, and has a
- *   function to get the alleged name for the kind of asset described. The
- *   alleged name (such as 'BTC' or 'moola') is provided by the maker of the
- *   issuer and should not be trusted as accurate.
- *
- *   Every amount created by a particular AmountMath will share the same brand,
- *   but recipients cannot rely on the brand to verify that a purported amount
- *   represents the issuer they intended, since the same brand can be reused by
- *   a misbehaving issuer.
- * @property {(allegedIssuer: ERef<Issuer>) => Promise<boolean>} isMyIssuer
+ * @template {AssetKind} K
+ * @typedef {object} BrandMethods
+ * @property {(allegedIssuer: ERef<Issuer<K>>) => Promise<boolean>} isMyIssuer
  *   Should be used with `issuer.getBrand` to ensure an issuer and brand match.
  * @property {() => string} getAllegedName
  * @property {() => DisplayInfo<K>} getDisplayInfo Give information to UI on how
@@ -113,6 +129,19 @@ export {};
  * @property {() => Pattern} getAmountShape
  */
 
+/**
+ * @template {AssetKind} [K=AssetKind]
+ * @typedef {RemotableObject & BrandMethods<K>} Brand The brand identifies the
+ *   kind of issuer, and has a function to get the alleged name for the kind of
+ *   asset described. The alleged name (such as 'BTC' or 'moola') is provided by
+ *   the maker of the issuer and should not be trusted as accurate.
+ *
+ *   Every amount created by a particular issuer will share the same brand, but
+ *   recipients cannot rely on the brand to verify that a purported amount
+ *   represents the issuer they intended, since the same brand can be reused by
+ *   a misbehaving issuer.
+ */
+
 // /////////////////////////// Issuer //////////////////////////////////////////
 
 /**
@@ -124,13 +153,14 @@ export {};
  */
 /**
  * @template {AssetKind} K
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
  * @callback IssuerGetAmountOf Get the amount of digital assets in the payment.
  *   Because the payment is not trusted, we cannot call a method on it directly,
  *   and must use the issuer instead.
  *
  *   If the payment is a promise, the operation will proceed upon fulfillment.
- * @param {ERef<Payment>} payment
- * @returns {Promise<Amount<K>>}
+ * @param {ERef<Payment<K, M>>} payment
+ * @returns {Promise<Amount<K, M>>}
  */
 
 /**
@@ -153,13 +183,9 @@ export {};
  */
 
 /**
- * @template {AssetKind} [K=AssetKind]
- * @typedef {object} Issuer The issuer cannot mint a new amount, but it can
- *   create empty purses and payments. The issuer can also transform payments
- *   (splitting payments, combining payments, burning payments, and claiming
- *   payments exclusively). The issuer should be gotten from a trusted source
- *   and then relied upon as the decider of whether an untrusted payment is
- *   valid.
+ * @template {AssetKind} K
+ * @template {Key} M
+ * @typedef {object} IssuerMethods Work around JSDoc union handling
  * @property {() => Brand<K>} getBrand Get the Brand for this Issuer. The Brand
  *   indicates the type of digital asset and is shared by the mint, the issuer,
  *   and any purses and payments of this particular kind. The brand is not
@@ -167,16 +193,28 @@ export {};
  *   alone. Fake digital assets and amount can use another issuer's brand.
  * @property {() => string} getAllegedName Get the allegedName for this
  *   mint/issuer
- * @property {() => AssetKind} getAssetKind Get the kind of MathHelpers used by
- *   this Issuer.
+ * @property {() => K} getAssetKind Get the kind of MathHelpers used by this
+ *   Issuer.
  * @property {() => DisplayInfo<K>} getDisplayInfo Give information to UI on how
  *   to display amounts for this issuer.
- * @property {() => Purse<K>} makeEmptyPurse Make an empty purse of this brand.
+ * @property {() => Purse<K, M>} makeEmptyPurse Make an empty purse of this
+ *   brand.
  * @property {IssuerIsLive} isLive
- * @property {IssuerGetAmountOf<K>} getAmountOf
+ * @property {IssuerGetAmountOf<K, M>} getAmountOf
  * @property {IssuerBurn} burn
  */
 
+/**
+ * @template {AssetKind} [K=AssetKind]
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
+ * @typedef {RemotableObject & IssuerMethods<K, M>} Issuer The issuer cannot
+ *   mint a new payment, but it can create empty purses and payments. The issuer
+ *   can also transform payments (splitting payments, combining payments,
+ *   burning payments, and claiming payments exclusively). The issuer should be
+ *   gotten from a trusted source and then relied upon as the decider of whether
+ *   an untrusted payment is valid.
+ */
+
 /**
  * @template {AssetKind} [K=AssetKind]
  * @typedef {object} PaymentLedger
@@ -190,12 +228,13 @@ export {};
 
 /**
  * @template {AssetKind} [K=AssetKind]
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
  * @typedef {object} IssuerKit
- * @property {Mint<K>} mint
- * @property {Purse<K>} mintRecoveryPurse Externally useful only if this issuer
- *   uses recovery sets. Can be used to get the recovery set associated with
- *   minted payments that are still live.
- * @property {Issuer<K>} issuer
+ * @property {Mint<K, M>} mint
+ * @property {Purse<K, M>} mintRecoveryPurse Externally useful only if this
+ *   issuer uses recovery sets. Can be used to get the recovery set associated
+ *   with minted payments that are still live.
+ * @property {Issuer<K, M>} issuer
  * @property {Brand<K>} brand
  * @property {DisplayInfo} displayInfo
  */
@@ -216,10 +255,11 @@ export {};
 
 /**
  * @template {AssetKind} [K=AssetKind]
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
  * @typedef {object} Mint Holding a Mint carries the right to issue new digital
  *   assets. These assets all have the same kind, which is called a Brand.
- * @property {() => Issuer<K>} getIssuer Gets the Issuer for this mint.
- * @property {(newAmount: Amount<K>) => Payment<K>} mintPayment Creates a new
+ * @property {() => Issuer<K, M>} getIssuer Gets the Issuer for this mint.
+ * @property {(newAmount: Amount<K>) => Payment<K, M>} mintPayment Creates a new
  *   Payment containing newly minted amount.
  */
 
@@ -261,40 +301,42 @@ export {};
  */
 
 /**
- * @template {AssetKind} K
- * @callback PurseDeposit
- * @param {Payment<K>} payment
- * @param {Pattern} [optAmountShape]
- * @returns {Amount<K>}
+ * @template {AssetKind} [K=AssetKind]
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
+ * @typedef {RemotableObject & PurseMethods<K, M>} Purse Purses hold amount of
+ *   digital assets of the same brand, but unlike Payments, they are not meant
+ *   to be sent to others. To transfer digital assets, a Payment should be
+ *   withdrawn from a Purse. The amount of digital assets in a purse can change
+ *   through the action of deposit() and withdraw().
  */
 
 /**
  * @template {AssetKind} [K=AssetKind]
- * @typedef {object} Purse Purses hold amount of digital assets of the same
- *   brand, but unlike Payments, they are not meant to be sent to others. To
- *   transfer digital assets, a Payment should be withdrawn from a Purse. The
- *   amount of digital assets in a purse can change through the action of
- *   deposit() and withdraw().
- *
- *   The primary use for Purses and Payments is for currency-like and goods-like
- *   digital assets, but they can also be used to represent other kinds of
- *   rights, such as the right to participate in a particular contract.
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
+ * @typedef {object} PurseMethods The primary use for Purses and Payments is for
+ *   currency-like and goods-like digital assets, but they can also be used to
+ *   represent other kinds of rights, such as the right to participate in a
+ *   particular contract.
  * @property {() => Brand<K>} getAllegedBrand Get the alleged Brand for this
  *   Purse
- * @property {() => Amount<K>} getCurrentAmount Get the amount contained in this
- *   purse.
- * @property {() => LatestTopic<Amount<K>>} getCurrentAmountNotifier Get a lossy
- *   notifier for changes to this purse's balance.
- * @property {PurseDeposit<K>} deposit Deposit all the contents of payment into
- *   this purse, returning the amount. If the optional argument `optAmount` does
- *   not equal the amount of digital assets in the payment, throw an error.
+ * @property {() => Amount<K, M>} getCurrentAmount Get the amount contained in
+ *   this purse.
+ * @property {() => LatestTopic<Amount<K, M>>} getCurrentAmountNotifier Get a
+ *   lossy notifier for changes to this purse's balance.
+ * @property {<P extends Payment<K, M>>(
+ *   payment: P,
+ *   optAmountShape?: Pattern,
+ * ) => P extends Payment<K, M> ? Amount<K, M> : never} deposit
+ *   Deposit all the contents of payment into this purse, returning the amount. If
+ *   the optional argument `optAmount` does not equal the amount of digital
+ *   assets in the payment, throw an error.
  *
  *   If payment is a promise, throw an error.
  * @property {() => DepositFacet} getDepositFacet Return an object whose
  *   `receive` method deposits to the current Purse.
- * @property {(amount: Amount<K>) => Payment<K>} withdraw Withdraw amount from
- *   this purse into a new Payment.
- * @property {() => CopySet<Payment<K>>} getRecoverySet The set of payments
+ * @property {(amount: Amount<K, M>) => Payment<K, M>} withdraw Withdraw amount
+ *   from this purse into a new Payment.
+ * @property {() => CopySet<Payment<K, M>>} getRecoverySet The set of payments
  *   withdrawn from this purse that are still live. These are the payments that
  *   can still be recovered in emergencies by, for example, depositing into this
  *   purse. Such a deposit action is like canceling an outstanding check because
@@ -304,22 +346,23 @@ export {};
  *   fails.
  *
  *   Returns an empty set if this issuer does not support recovery sets.
- * @property {() => Amount<K>} recoverAll For use in emergencies, such as coming
- *   back from a traumatic crash and upgrade. This deposits all the payments in
- *   this purse's recovery set into the purse itself, returning the total amount
- *   of assets recovered.
+ * @property {() => Amount<K, M>} recoverAll For use in emergencies, such as
+ *   coming back from a traumatic crash and upgrade. This deposits all the
+ *   payments in this purse's recovery set into the purse itself, returning the
+ *   total amount of assets recovered.
  *
  *   Returns an empty amount if this issuer does not support recovery sets.
  */
 
 /**
  * @template {AssetKind} [K=AssetKind]
- * @typedef {object} Payment Payments hold amount of digital assets of the same
- *   brand in transit. Payments can be deposited in purses, split into multiple
- *   payments, combined, and claimed (getting an exclusive payment). Payments
- *   are linear, meaning that either a payment has the same amount of digital
- *   assets it started with, or it is used up entirely. It is impossible to
- *   partially use a payment.
+ * @template {Key} [M=Key] member kind, for Amounts that have member values
+ * @typedef {RemotableObject & PaymentMethods<K>} Payment Payments hold amount
+ *   of digital assets of the same brand in transit. Payments can be deposited
+ *   in purses, split into multiple payments, combined, and claimed (getting an
+ *   exclusive payment). Payments are linear, meaning that either a payment has
+ *   the same amount of digital assets it started with, or it is used up
+ *   entirely. It is impossible to partially use a payment.
  *
  *   Payments are often received from other actors and therefore should not be
  *   trusted themselves. To get the amount of digital assets in a payment, use
@@ -328,6 +371,11 @@ export {};
  *   Payments can be converted to Purses by getting a trusted issuer and calling
  *   `issuer.makeEmptyPurse()` to create a purse, then
  *   `purse.deposit(payment)`.
+ */
+
+/**
+ * @template {AssetKind} [K=AssetKind]
+ * @typedef {object} PaymentMethods
  * @property {() => Brand<K>} getAllegedBrand Get the allegedBrand, indicating
  *   the type of digital asset this payment purports to be, and which issuer to
  *   use. Because payments are not trusted, any method calls on payments should
@@ -366,4 +414,7 @@ export {};
 
 /** @typedef {bigint} NatValue */
 
-/** @typedef {Key[]} SetValue */
+/**
+ * @template {Key} [K=Key]
+ * @typedef {K[]} SetValue
+ */
diff --git a/packages/ERTP/test/swingsetTests/basicFunctionality/bootstrap.js b/packages/ERTP/test/swingsetTests/basicFunctionality/bootstrap.js
index 1e70311929d..7fc825aff33 100644
--- a/packages/ERTP/test/swingsetTests/basicFunctionality/bootstrap.js
+++ b/packages/ERTP/test/swingsetTests/basicFunctionality/bootstrap.js
@@ -9,7 +9,8 @@ export function buildRootObject(vatPowers, vatParameters) {
   function testBasicFunctionality(aliceMaker) {
     vatPowers.testLog('start test basic functionality');
     const { mint: moolaMint, issuer, brand } = makeIssuerKit('moola');
-    const moolaPayment = moolaMint.mintPayment(AmountMath.make(brand, 1000n));
+    const amt = AmountMath.make(brand, 1000n);
+    const moolaPayment = moolaMint.mintPayment(amt);
 
     const aliceP = E(aliceMaker).make(issuer, brand, moolaPayment);
     return E(aliceP).testBasicFunctionality();
diff --git a/packages/ERTP/test/types.test-d.ts b/packages/ERTP/test/types.test-d.ts
index 35d024da98e..41102e8629e 100644
--- a/packages/ERTP/test/types.test-d.ts
+++ b/packages/ERTP/test/types.test-d.ts
@@ -1,11 +1,12 @@
 import { Far } from '@endo/marshal';
+import type { Key } from '@endo/patterns';
 import { expectType } from 'tsd';
-
 import { AmountMath, AssetKind } from '../src/index.js';
 import type {
   Amount,
   AssetValueForKind,
   Brand,
+  Issuer,
   SetValue,
 } from '../src/types.js';
 
@@ -18,7 +19,7 @@ import type {
   expectType<never>(AmountMath.makeEmpty(brand, AssetKind.SET));
 
   expectType<Amount<'nat'>>(AmountMath.make(brand, 1n));
-  // @ts-expect-error invalid value for brand
+  // @ts-expect-error invalid value for amount
   AmountMath.make(brand, {});
 }
 
@@ -26,10 +27,10 @@ import type {
   const brand: Brand<'set'> = Far('setbrand');
   expectType<Amount<'set'>>(AmountMath.makeEmpty(brand, 'set'));
   expectType<Amount<'set'>>(AmountMath.make(brand, []));
-  // @ts-expect-error TODO
-  expectType<never>(AmountMath.make(brand, AssetKind.NAT));
 
-  // @ts-expect-error invalid value for brand
+  // @ts-expect-error invalid value for amount
+  AmountMath.make(brand, AssetKind.NAT);
+  // @ts-expect-error invalid value for amount
   AmountMath.make(brand, {});
 }
 
@@ -43,3 +44,8 @@ import type {
   // @ts-expect-error 'n' doesn't satisfy AssetKind
   const n: AssetValueForKind<'n'> = null;
 }
+
+{
+  const issuer: Issuer = null as any;
+  expectType<Key>(issuer);
+}
diff --git a/packages/ERTP/test/unitTests/mathHelpers/mockBrand.js b/packages/ERTP/test/unitTests/mathHelpers/mockBrand.js
index 14f21b5c7ed..a4ad9feeeeb 100644
--- a/packages/ERTP/test/unitTests/mathHelpers/mockBrand.js
+++ b/packages/ERTP/test/unitTests/mathHelpers/mockBrand.js
@@ -1,15 +1,52 @@
 import { Far } from '@endo/marshal';
 import { AssetKind } from '../../../src/index.js';
 
-/** @import {Brand} from '../../../src/types.js'; */
+/** @import {Brand} from '@agoric/ertp/src/types.js'; */
 
-/** @type {Brand<AssetKind>} */
-export const mockBrand = Far('brand', {
+/** @type {Brand<'nat'>} */
+// @ts-expect-error FIXME losing PASS_STYLE
+export const mockNatBrand = Far('brand', {
   // eslint-disable-next-line no-unused-vars
   isMyIssuer: async allegedIssuer => false,
   getAllegedName: () => 'mock',
-  getAmountShape: () => {},
+  getAmountShape: () => ({}),
   getDisplayInfo: () => ({
     assetKind: AssetKind.NAT,
   }),
 });
+
+/** @type {Brand<'set'>} */
+// @ts-expect-error FIXME losing PASS_STYLE
+export const mockSetBrand = Far('brand', {
+  // eslint-disable-next-line no-unused-vars
+  isMyIssuer: async allegedIssuer => false,
+  getAllegedName: () => 'mock',
+  getAmountShape: () => ({}),
+  getDisplayInfo: () => ({
+    assetKind: AssetKind.SET,
+  }),
+});
+
+/** @type {Brand<'copySet'>} */
+// @ts-expect-error FIXME losing PASS_STYLE
+export const mockCopySetBrand = Far('brand', {
+  // eslint-disable-next-line no-unused-vars
+  isMyIssuer: async allegedIssuer => false,
+  getAllegedName: () => 'mock',
+  getAmountShape: () => ({}),
+  getDisplayInfo: () => ({
+    assetKind: AssetKind.COPY_SET,
+  }),
+});
+
+/** @type {Brand<'copyBag'>} */
+// @ts-expect-error FIXME losing PASS_STYLE
+export const mockCopyBagBrand = Far('brand', {
+  // eslint-disable-next-line no-unused-vars
+  isMyIssuer: async allegedIssuer => false,
+  getAllegedName: () => 'mock',
+  getAmountShape: () => ({}),
+  getDisplayInfo: () => ({
+    assetKind: AssetKind.COPY_BAG,
+  }),
+});
diff --git a/packages/ERTP/test/unitTests/mathHelpers/test-copyBagMathHelpers.js b/packages/ERTP/test/unitTests/mathHelpers/test-copyBagMathHelpers.js
index b3e7e6df9cf..1f71539d790 100644
--- a/packages/ERTP/test/unitTests/mathHelpers/test-copyBagMathHelpers.js
+++ b/packages/ERTP/test/unitTests/mathHelpers/test-copyBagMathHelpers.js
@@ -6,7 +6,7 @@ import {
 } from '@agoric/store';
 
 import { AmountMath as m, AssetKind } from '../../../src/index.js';
-import { mockBrand } from './mockBrand.js';
+import { mockCopyBagBrand as mockBrand } from './mockBrand.js';
 
 // The "unit tests" for MathHelpers actually make the calls through
 // AmountMath so that we can test that any duplication is handled
diff --git a/packages/ERTP/test/unitTests/mathHelpers/test-copySetMathHelpers.js b/packages/ERTP/test/unitTests/mathHelpers/test-copySetMathHelpers.js
index d100c50938b..a0171c5fa38 100644
--- a/packages/ERTP/test/unitTests/mathHelpers/test-copySetMathHelpers.js
+++ b/packages/ERTP/test/unitTests/mathHelpers/test-copySetMathHelpers.js
@@ -2,7 +2,7 @@ import { test } from '@agoric/swingset-vat/tools/prepare-test-env-ava.js';
 import { getCopySetKeys, makeCopySet } from '@agoric/store';
 
 import { AmountMath as m, AssetKind } from '../../../src/index.js';
-import { mockBrand } from './mockBrand.js';
+import { mockCopySetBrand as mockBrand } from './mockBrand.js';
 
 /** @import {CopySet} from '@endo/patterns' */
 
@@ -209,6 +209,7 @@ test('copySet with strings add', t => {
     () =>
       m.add(
         harden({ brand: mockBrand, value: makeCopySet(['a', 'a']) }),
+        // @ts-expect-error deliberate invalid arguments for testing
         harden({ brand: mockBrand, value: makeCopySet(['b']) }),
       ),
     { message: /value has duplicate(| key)s: "a"/ },
@@ -218,6 +219,7 @@ test('copySet with strings add', t => {
     () =>
       m.add(
         harden({ brand: mockBrand, value: makeCopySet(['a']) }),
+        // @ts-expect-error deliberate invalid arguments for testing
         harden({ brand: mockBrand, value: makeCopySet(['b', 'b']) }),
       ),
     { message: /value has duplicate(| key)s: "b"/ },
diff --git a/packages/ERTP/test/unitTests/mathHelpers/test-natMathHelpers.js b/packages/ERTP/test/unitTests/mathHelpers/test-natMathHelpers.js
index d43164ce474..9e19389a8b4 100644
--- a/packages/ERTP/test/unitTests/mathHelpers/test-natMathHelpers.js
+++ b/packages/ERTP/test/unitTests/mathHelpers/test-natMathHelpers.js
@@ -3,7 +3,7 @@ import { M } from '@agoric/store';
 
 import { Far } from '@endo/marshal';
 import { AmountMath as m, AssetKind } from '../../../src/index.js';
-import { mockBrand } from './mockBrand.js';
+import { mockNatBrand as mockBrand } from './mockBrand.js';
 
 // The "unit tests" for MathHelpers actually make the calls through
 // AmountMath so that we can test that any duplication is handled
diff --git a/packages/ERTP/test/unitTests/mathHelpers/test-setMathHelpers.js b/packages/ERTP/test/unitTests/mathHelpers/test-setMathHelpers.js
index 716df4ea092..35c58878150 100644
--- a/packages/ERTP/test/unitTests/mathHelpers/test-setMathHelpers.js
+++ b/packages/ERTP/test/unitTests/mathHelpers/test-setMathHelpers.js
@@ -3,7 +3,7 @@ import { test } from '@agoric/swingset-vat/tools/prepare-test-env-ava.js';
 import { Far } from '@endo/marshal';
 
 import { AmountMath as m, AssetKind } from '../../../src/index.js';
-import { mockBrand } from './mockBrand.js';
+import { mockSetBrand as mockBrand } from './mockBrand.js';
 
 // The "unit tests" for MathHelpers actually make the calls through
 // AmountMath so that we can test that any duplication is handled
diff --git a/packages/ERTP/test/unitTests/mathHelpers/test-strSetMathHelpers.js b/packages/ERTP/test/unitTests/mathHelpers/test-strSetMathHelpers.js
index 8dd4e886e9a..0677b9b81bf 100644
--- a/packages/ERTP/test/unitTests/mathHelpers/test-strSetMathHelpers.js
+++ b/packages/ERTP/test/unitTests/mathHelpers/test-strSetMathHelpers.js
@@ -1,7 +1,7 @@
 import { test } from '@agoric/swingset-vat/tools/prepare-test-env-ava.js';
 
 import { AmountMath as m, AssetKind } from '../../../src/index.js';
-import { mockBrand } from './mockBrand.js';
+import { mockSetBrand as mockBrand } from './mockBrand.js';
 
 // The "unit tests" for MathHelpers actually make the calls through
 // AmountMath so that we can test that any duplication is handled
diff --git a/packages/ERTP/test/unitTests/test-amountProperties.js b/packages/ERTP/test/unitTests/test-amountProperties.js
index 6bfa2d71878..fabe0ebb3f3 100644
--- a/packages/ERTP/test/unitTests/test-amountProperties.js
+++ b/packages/ERTP/test/unitTests/test-amountProperties.js
@@ -3,7 +3,7 @@ import { makeCopyBag } from '@agoric/store';
 import { fc } from '@fast-check/ava';
 
 import { AmountMath as m, AssetKind } from '../../src/index.js';
-import { mockBrand } from './mathHelpers/mockBrand.js';
+import { mockCopyBagBrand as mockBrand } from './mathHelpers/mockBrand.js';
 
 // Perhaps makeCopyBag should coalesce duplicate labels, but for now, it does
 // not.
diff --git a/packages/ERTP/test/unitTests/test-inputValidation.js b/packages/ERTP/test/unitTests/test-inputValidation.js
index a1c14adcd50..1f87699fc6d 100644
--- a/packages/ERTP/test/unitTests/test-inputValidation.js
+++ b/packages/ERTP/test/unitTests/test-inputValidation.js
@@ -144,7 +144,7 @@ test('brand.isMyIssuer bad issuer', async t => {
     message:
       /In "isMyIssuer" method of \(myTokens brand\): arg 0: .*"not an issuer" - Must be a remotable/,
   });
-  const fakeIssuer = /** @type {Issuer} */ (
+  const fakeIssuer = /** @type {Issuer<'nat'>} */ (
     /** @type {unknown} */ (Far('myTokens issuer', {}))
   );
   const result = await brand.isMyIssuer(fakeIssuer);
diff --git a/packages/ERTP/test/unitTests/test-legacy-payment-helpers.js b/packages/ERTP/test/unitTests/test-legacy-payment-helpers.js
index 2776d06f2dd..43eee8e7e6d 100644
--- a/packages/ERTP/test/unitTests/test-legacy-payment-helpers.js
+++ b/packages/ERTP/test/unitTests/test-legacy-payment-helpers.js
@@ -9,6 +9,7 @@ const { isEqual } = AmountMath;
 test('no lost assets on non-atomic combine failure', async t => {
   const { issuer, mint, brand } = makeIssuerKit('precious');
   const recoveryPurse = issuer.makeEmptyPurse();
+  /** @param {bigint} num */
   const precious = num => AmountMath.make(brand, num);
   const payment1 = mint.mintPayment(precious(39n));
   const payment2 = payment1; // "accidental" aliasing
@@ -26,6 +27,7 @@ test('no lost assets on non-atomic combine failure', async t => {
 test('no lost assets on non-atomic split failure', async t => {
   const { issuer, mint, brand } = makeIssuerKit('precious');
   const recoveryPurse = issuer.makeEmptyPurse();
+  /** @param {bigint} num */
   const precious = num => AmountMath.make(brand, num);
   const srcPayment = mint.mintPayment(precious(78n));
   await t.throwsAsync(() => split(recoveryPurse, srcPayment, precious(100n)), {
diff --git a/packages/ERTP/test/unitTests/test-recovery.js b/packages/ERTP/test/unitTests/test-recovery.js
index 3ed6ef326a7..92713b8ef83 100644
--- a/packages/ERTP/test/unitTests/test-recovery.js
+++ b/packages/ERTP/test/unitTests/test-recovery.js
@@ -8,6 +8,7 @@ const emptySet = makeCopySet([]);
 
 test('payment recovery from purse recovery set', async t => {
   const { issuer, mint, brand } = makeIssuerKit('precious');
+  /** @param {bigint} num */
   const precious = num => AmountMath.make(brand, num);
   const payment1 = mint.mintPayment(precious(37n));
   const payment2 = mint.mintPayment(precious(41n));
@@ -42,6 +43,7 @@ test('payment recovery from purse recovery set', async t => {
 
 test('payment recovery from mint recovery set', async t => {
   const { issuer, mint, mintRecoveryPurse, brand } = makeIssuerKit('precious');
+  /** @param {bigint} num */
   const precious = num => AmountMath.make(brand, num);
   const mindyPurse = issuer.makeEmptyPurse();
   const bobPurse = issuer.makeEmptyPurse();
diff --git a/packages/SwingSet/misc-tools/classify-promises.js b/packages/SwingSet/misc-tools/classify-promises.js
index 63bafaaf998..410d2b9dbd8 100755
--- a/packages/SwingSet/misc-tools/classify-promises.js
+++ b/packages/SwingSet/misc-tools/classify-promises.js
@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+// @ts-nocheck XXX
 /* eslint no-labels: "off", no-extra-label: "off", no-underscore-dangle: "off" */
 import process from 'process';
 import sqlite3 from 'better-sqlite3';
diff --git a/packages/SwingSet/package.json b/packages/SwingSet/package.json
index 53a803a78ff..425ddcbe761 100644
--- a/packages/SwingSet/package.json
+++ b/packages/SwingSet/package.json
@@ -100,6 +100,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 75.02
+    "atLeast": 74.99
   }
 }
diff --git a/packages/SwingSet/src/controller/initializeKernel.js b/packages/SwingSet/src/controller/initializeKernel.js
index 67552acf629..3378a28c39f 100644
--- a/packages/SwingSet/src/controller/initializeKernel.js
+++ b/packages/SwingSet/src/controller/initializeKernel.js
@@ -212,6 +212,7 @@ export async function initializeKernel(config, kernelStorage, options = {}) {
       // See https://github.com/Agoric/agoric-sdk/issues/2780
       errorIdNum: 60_000,
     });
+    // @ts-expect-error xxx
     const args = kunser(m.serialize(harden([vatObj0s, deviceObj0s])));
     const rootKref = exportRootObject(kernelKeeper, bootstrapVatID);
     const resultKpid = queueToKref(rootKref, 'bootstrap', args, 'panic');
diff --git a/packages/SwingSet/src/devices/bundle/device-bundle.js b/packages/SwingSet/src/devices/bundle/device-bundle.js
index d4038c9d935..1b3dfa74d77 100644
--- a/packages/SwingSet/src/devices/bundle/device-bundle.js
+++ b/packages/SwingSet/src/devices/bundle/device-bundle.js
@@ -103,6 +103,7 @@ export function buildDevice(tools, endowments) {
 
   const dispatch = {
     invoke: (dnid, method, argsCapdata) => {
+      /** @type {any} */
       const args = unserialize(argsCapdata);
 
       if (dnid === ROOT) {
diff --git a/packages/SwingSet/src/devices/vat-admin/device-vat-admin.js b/packages/SwingSet/src/devices/vat-admin/device-vat-admin.js
index 59e9d583852..7e2667d87b3 100644
--- a/packages/SwingSet/src/devices/vat-admin/device-vat-admin.js
+++ b/packages/SwingSet/src/devices/vat-admin/device-vat-admin.js
@@ -172,6 +172,7 @@ export function buildDevice(tools, endowments) {
 
         // D(devices.vatAdmin).addMeterRemaining(meterID, delta)
         if (method === 'addMeterRemaining') {
+          /** @type {any} */
           const args = unserialize(argsCapdata);
           const [meterID, delta] = args;
           assert.typeof(meterID, 'string', 'addMeterRemaining() meterID');
@@ -182,6 +183,7 @@ export function buildDevice(tools, endowments) {
 
         // D(devices.vatAdmin).setMeterThreshold(meterID, threshold)
         if (method === 'setMeterThreshold') {
+          /** @type {any} */
           const args = unserialize(argsCapdata);
           const [meterID, threshold] = args;
           assert.typeof(meterID, 'string', 'setMeterThreshold() meterID');
@@ -192,6 +194,7 @@ export function buildDevice(tools, endowments) {
 
         // D(devices.vatAdmin).getMeter(meterID) -> { remaining, threshold }
         if (method === 'getMeter') {
+          /** @type {any} */
           const args = unserialize(argsCapdata);
           const [meterID] = args;
           assert.typeof(meterID, 'string', 'getMeter() meterID');
@@ -265,6 +268,7 @@ export function buildDevice(tools, endowments) {
         // D(devices.bundle).getBundleCap(id) -> bundlecap
         if (method === 'getBundleCap') {
           const args = unserialize(argsCapdata);
+          /** @type {any} */
           const [bundleID] = args;
           assert.typeof(bundleID, 'string', 'getBundleCap() bundleID');
           assert(bundleIDRE.test(bundleID), 'getBundleCap() not a bundleID');
@@ -273,6 +277,7 @@ export function buildDevice(tools, endowments) {
         // D(devices.bundle).getNamedBundleCap(name) -> bundlecap
         if (method === 'getNamedBundleCap') {
           const args = unserialize(argsCapdata);
+          /** @type {any} */
           const [name] = args;
           assert.typeof(name, 'string', 'getNamedBundleCap() name');
           let bundleID;
@@ -287,6 +292,7 @@ export function buildDevice(tools, endowments) {
         // D(devices.bundle).getBundleIDByName(name) -> id
         if (method === 'getBundleIDByName') {
           const args = unserialize(argsCapdata);
+          /** @type {any} */
           const [name] = args;
           assert.typeof(name, 'string', 'getBundleIDByName() name');
           let bundleID;
diff --git a/packages/SwingSet/src/types-external.js b/packages/SwingSet/src/types-external.js
index b27d225eacb..3c856bbc399 100644
--- a/packages/SwingSet/src/types-external.js
+++ b/packages/SwingSet/src/types-external.js
@@ -2,6 +2,11 @@
 
 export {};
 
+/**
+ * @import {Guarded} from '@endo/exo';
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ */
+
 /* This file defines types that part of the external API of swingset. That
  * includes standard services which user-provided vat code might interact
  * with, like VatAdminService. */
@@ -350,9 +355,7 @@ export {};
  * incarnation.
  *
  *
- * @typedef {object} CreateVatResults
- * @property {object} root
- * @property {VatAdminFacet} adminNode
+ * @typedef {{ adminNode: Guarded<VatAdminFacet>, root: object }} CreateVatResults
  *
  * @typedef {object} VatAdminSvc
  * @property {(id: BundleID) => ERef<BundleCap>} waitForBundleCap
diff --git a/packages/SwingSet/src/vats/timer/vat-timer.js b/packages/SwingSet/src/vats/timer/vat-timer.js
index 9dfb411c62f..e9ed5d987b7 100644
--- a/packages/SwingSet/src/vats/timer/vat-timer.js
+++ b/packages/SwingSet/src/vats/timer/vat-timer.js
@@ -15,6 +15,11 @@ import {
 import { makeScalarWeakMapStore } from '@agoric/store';
 import { TimeMath } from '@agoric/time';
 
+/**
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ * @import {Key} from '@endo/patterns';
+ */
+
 // This consumes O(N) RAM only for outstanding promises, via wakeAt(),
 // delay(), and Notifiers/Iterators (for each actively-waiting
 // client). Everything else should remain in the DB.
@@ -31,10 +36,10 @@ import { TimeMath } from '@agoric/time';
  * Handler is a user-provided Far object with .wake(time) used for callbacks
  * @property {(scheduled: Timestamp) => unknown} wake
  *
- * @typedef {unknown} CancelToken
+ * @typedef {Key} CancelToken
  * CancelToken must be pass-by-reference and durable, either local or remote
  *
- * @typedef {{
+ * @typedef {RemotableObject & {
  *  scheduleYourself: () => void,
  *  fired: (now: TimestampValue) => void,
  *  cancel: () => void,
@@ -42,7 +47,7 @@ import { TimeMath } from '@agoric/time';
  *
  * @typedef {MapStore<TimestampValue, Event[]>} Schedule
  *
- * @typedef {{ cancel: () => void }} Cancellable
+ * @typedef {RemotableObject & { cancel: () => void }} Cancellable
  *
  * @typedef {WeakMapStore<CancelToken, Cancellable[]>} CancelTable
  *
diff --git a/packages/SwingSet/test/devices/device-raw-0.js b/packages/SwingSet/test/devices/device-raw-0.js
index 63e673f3dd3..d4e1ff1021b 100644
--- a/packages/SwingSet/test/devices/device-raw-0.js
+++ b/packages/SwingSet/test/devices/device-raw-0.js
@@ -17,6 +17,7 @@ export function buildDevice(tools, endowments) {
 
   const dispatch = {
     invoke: (dnid, method, argsCapdata) => {
+      /** @type {any} */
       const args = unserialize(argsCapdata);
 
       if (dnid === ROOT) {
diff --git a/packages/agoric-cli/package.json b/packages/agoric-cli/package.json
index 2bf0150b58d..bbf2447c283 100644
--- a/packages/agoric-cli/package.json
+++ b/packages/agoric-cli/package.json
@@ -98,6 +98,6 @@
     "workerThreads": false
   },
   "typeCoverage": {
-    "atLeast": 76.98
+    "atLeast": 76.88
   }
 }
diff --git a/packages/agoric-cli/src/commands/auction.js b/packages/agoric-cli/src/commands/auction.js
index 78e3d8a8515..a056c6805e5 100644
--- a/packages/agoric-cli/src/commands/auction.js
+++ b/packages/agoric-cli/src/commands/auction.js
@@ -156,6 +156,7 @@ export const makeAuctionCommand = (
             previousOffer: opts.charterAcceptOfferId,
             invitationMakerName: 'VoteOnParamChange',
           },
+          // @ts-expect-error XXX governance types
           offerArgs,
           proposal: {},
         };
diff --git a/packages/agoric-cli/src/commands/inter.js b/packages/agoric-cli/src/commands/inter.js
index f8353d41c8b..ff181d5d0ec 100644
--- a/packages/agoric-cli/src/commands/inter.js
+++ b/packages/agoric-cli/src/commands/inter.js
@@ -147,7 +147,7 @@ export const fmtBid = (bid, assets) => {
   /** @type {{ price: string } | { discount: number }} */
   const spec =
     'offerPrice' in offerArgs
-      ? { price: fmt.price(offerArgs.offerPrice) }
+      ? { price: fmt.price(/** @type {Ratio} */ (offerArgs.offerPrice)) }
       : { discount: fmt.discount(offerArgs.offerBidScaling) };
 
   const {
diff --git a/packages/agoric-cli/src/commands/psm.js b/packages/agoric-cli/src/commands/psm.js
index 1daaa99f503..3142fbdbc0e 100644
--- a/packages/agoric-cli/src/commands/psm.js
+++ b/packages/agoric-cli/src/commands/psm.js
@@ -262,6 +262,7 @@ export const makePsmCommand = logger => {
           invitationMakerName: 'VoteOnParamChange',
         },
         proposal: {},
+        // @ts-expect-error XXX governance types
         offerArgs: {
           instance: psmInstance,
           params: { MintLimit: scaledAmount },
diff --git a/packages/agoric-cli/src/lib/format.js b/packages/agoric-cli/src/lib/format.js
index cad70a023dc..9e50c4d6e33 100644
--- a/packages/agoric-cli/src/lib/format.js
+++ b/packages/agoric-cli/src/lib/format.js
@@ -54,7 +54,9 @@ export const makeAmountFormatter = assets => amt => {
       return [issuerName, Number(value) / 10 ** decimalPlaces];
     case 'set':
       assert(Array.isArray(value));
+      // @ts-expect-error narrowed
       if (value[0]?.handle?.iface?.includes('InvitationHandle')) {
+        // @ts-expect-error narrowed
         return [issuerName, value.map(v => v.description)];
       }
       return [issuerName, value];
diff --git a/packages/agoric-cli/src/lib/wallet.js b/packages/agoric-cli/src/lib/wallet.js
index 2aa1e1fe454..610135d2910 100644
--- a/packages/agoric-cli/src/lib/wallet.js
+++ b/packages/agoric-cli/src/lib/wallet.js
@@ -187,7 +187,7 @@ export const sendAction = async (bridgeAction, opts) => {
  */
 export const findContinuingIds = (current, agoricNames) => {
   // XXX should runtime type-check
-  /** @type {{ offerToUsedInvitation: [string, Amount<'set'>][]}} */
+  /** @type {{ offerToUsedInvitation: [string, InvitationAmount][]}} */
   const { offerToUsedInvitation: entries } = /** @type {any} */ (current);
 
   Array.isArray(entries) || Fail`entries must be an array: ${entries}`;
diff --git a/packages/base-zone/package.json b/packages/base-zone/package.json
index 2dbfe953103..f7ea86438bc 100644
--- a/packages/base-zone/package.json
+++ b/packages/base-zone/package.json
@@ -56,6 +56,6 @@
     "workerThreads": false
   },
   "typeCoverage": {
-    "atLeast": 88.55
+    "atLeast": 89.87
   }
 }
diff --git a/packages/base-zone/src/heap.js b/packages/base-zone/src/heap.js
index 3445255e8d5..fe6a6a72918 100644
--- a/packages/base-zone/src/heap.js
+++ b/packages/base-zone/src/heap.js
@@ -12,6 +12,7 @@ import {
 
 import { makeOnceKit } from './make-once.js';
 import { agoricVatDataKeys as keys } from './keys.js';
+import { watchPromise } from './watch-promise.js';
 
 /**
  * @type {import('./types.js').Stores}
@@ -49,6 +50,7 @@ export const makeHeapZone = (baseLabel = 'heapZone') => {
     subZone: wrapProvider(makeSubZone),
 
     makeOnce,
+    watchPromise,
     detached: detachedHeapStores.detached,
     isStorable: detachedHeapStores.isStorable,
 
diff --git a/packages/base-zone/src/index.js b/packages/base-zone/src/index.js
index a7b2ee98e34..7a137f7d54f 100644
--- a/packages/base-zone/src/index.js
+++ b/packages/base-zone/src/index.js
@@ -10,3 +10,4 @@ export * from './exports.js';
 export * from './make-once.js';
 export * from './keys.js';
 export * from './is-passable.js';
+export * from './watch-promise.js';
diff --git a/packages/base-zone/src/types.js b/packages/base-zone/src/types.js
index 207c949837d..26ddc574df4 100644
--- a/packages/base-zone/src/types.js
+++ b/packages/base-zone/src/types.js
@@ -1,9 +1,16 @@
 // eslint-disable-next-line no-unused-vars
 import { makeExo, defineExoClass, defineExoClassKit } from '@endo/exo';
+// eslint-disable-next-line no-unused-vars
+import { watchPromise } from './watch-promise.js';
 
 // Ensure this is a module.
 export {};
 
+/**
+ * @import {Key} from '@endo/patterns';
+ * @import {Passable} from '@endo/pass-style';
+ */
+
 /** @typedef {'exoClass' | 'exoClassKit' | 'exo' | 'store' | 'zone'} KeyCategories */
 /** @typedef {Record<KeyCategories, (label: string) => string[]>} KeyMakers */
 
@@ -19,15 +26,16 @@ export {};
  * @property {typeof defineExoClassKit} exoClassKit create a "kit" maker function that can be used to create a record of exo-objects sharing the same state
  * @property {<T>(key: string, maker: (key: string) => T) => T} makeOnce create or retrieve a singleton object bound to this zone
  * @property {(label: string, options?: StoreOptions) => Zone} subZone create a new Zone that can be passed to untrusted consumers without exposing the storage of the parent zone
+ * @property {typeof watchPromise} watchPromise register a promise watcher created by this zone
  */
 
 /**
  * @typedef {object} Stores
  * @property {() => Stores} detached obtain store providers which are detached (the stores are anonymous rather than bound to `label` in the zone)
  * @property {(specimen: unknown) => boolean} isStorable return true if the specimen can be stored in the zone, whether as exo-object state or in a store
- * @property {<K,V>(label: string, options?: StoreOptions) => MapStore<K, V>} mapStore provide a Map-like store named `label` in the zone
+ * @property {(label: string, options?: StoreOptions) => MapStore<any, any>} mapStore provide a Map-like store named `label` in the zone
  * @property {<K>(label: string, options?: StoreOptions) => SetStore<K>} setStore provide a Set-like store named `label` in the zone
- * @property {<K,V>(
+ * @property {<K, V>(
  *   label: string, options?: StoreOptions) => WeakMapStore<K, V>
  * } weakMapStore provide a WeakMap-like store named `label` in the zone
  * @property {<K>(
diff --git a/packages/vow/src/watch-promise.js b/packages/base-zone/src/watch-promise.js
similarity index 62%
rename from packages/vow/src/watch-promise.js
rename to packages/base-zone/src/watch-promise.js
index 2b7b403802d..4693bd98377 100644
--- a/packages/vow/src/watch-promise.js
+++ b/packages/base-zone/src/watch-promise.js
@@ -1,15 +1,36 @@
 // @ts-check
 import { M } from '@endo/patterns';
-
-import { basicE } from './vow-utils.js';
+import { E } from '@endo/far';
 
 const { Fail } = assert;
 
 const { apply } = Reflect;
 
+/**
+ * A PromiseWatcher method guard callable with or more arguments, returning void.
+ */
+export const PromiseWatcherHandler = M.call(M.any()).rest(M.any()).returns();
+
+/**
+ * A PromiseWatcher interface that has both onFulfilled and onRejected handlers.
+ */
 export const PromiseWatcherI = M.interface('PromiseWatcher', {
-  onFulfilled: M.call(M.any()).rest(M.any()).returns(),
-  onRejected: M.call(M.any()).rest(M.any()).returns(),
+  onFulfilled: PromiseWatcherHandler,
+  onRejected: PromiseWatcherHandler,
+});
+
+/**
+ * A PromiseWatcher interface that has only an onFulfilled handler.
+ */
+export const PromiseWatcherFulfilledI = M.interface('PromiseWatcherFulfilled', {
+  onFulfilled: PromiseWatcherHandler,
+});
+
+/**
+ * A PromiseWatcher interface that has only an onRejected handler.
+ */
+export const PromiseWatcherRejectedI = M.interface('PromiseWatcherRejected', {
+  onRejected: PromiseWatcherHandler,
 });
 
 /**
@@ -49,13 +70,13 @@ const callMeMaybe = (that, prop, postArgs) => {
  * @param {...unknown} watcherArgs
  * @returns {void}
  */
-export const watchPromiseShim = (p, watcher, ...watcherArgs) => {
+export const watchPromise = (p, watcher, ...watcherArgs) => {
   Promise.resolve(p) === p || Fail`watchPromise only watches promises`;
   const onFulfilled = callMeMaybe(watcher, 'onFulfilled', watcherArgs);
   const onRejected = callMeMaybe(watcher, 'onRejected', watcherArgs);
   onFulfilled ||
     onRejected ||
     Fail`promise watcher must implement at least one handler method`;
-  void basicE.when(p, onFulfilled, onRejected);
+  void E.when(p, onFulfilled, onRejected);
 };
-harden(watchPromiseShim);
+harden(watchPromise);
diff --git a/packages/boot/package.json b/packages/boot/package.json
index c5723f500f2..a514b9b92e2 100644
--- a/packages/boot/package.json
+++ b/packages/boot/package.json
@@ -90,6 +90,6 @@
     "workerThreads": false
   },
   "typeCoverage": {
-    "atLeast": 85.88
+    "atLeast": 86.47
   }
 }
diff --git a/packages/boot/test/bootstrapTests/test-vaults-integration.ts b/packages/boot/test/bootstrapTests/test-vaults-integration.ts
index 9d66c9a6f3b..ac78dee6cab 100644
--- a/packages/boot/test/bootstrapTests/test-vaults-integration.ts
+++ b/packages/boot/test/bootstrapTests/test-vaults-integration.ts
@@ -339,6 +339,7 @@ test('propose change to auction governance param', async t => {
       previousOffer: 'accept-charter-invitation',
       invitationMakerName: 'VoteOnParamChange',
     },
+    // @ts-expect-error XXX governance types
     offerArgs,
     proposal: {},
   });
diff --git a/packages/boot/tools/drivers.ts b/packages/boot/tools/drivers.ts
index b2464856d2d..431edc437b3 100644
--- a/packages/boot/tools/drivers.ts
+++ b/packages/boot/tools/drivers.ts
@@ -96,25 +96,21 @@ export const makeWalletFactoryDriver = async (
     },
 
     getCurrentWalletRecord(): CurrentWalletRecord {
-      const fromCapData = (...args) =>
-        Reflect.apply(marshaller.fromCapData, marshaller, args);
       return unmarshalFromVstorage(
         storage.data,
         `published.wallet.${walletAddress}.current`,
-        fromCapData,
+        (...args) => Reflect.apply(marshaller.fromCapData, marshaller, args),
         -1,
-      );
+      ) as any;
     },
 
     getLatestUpdateRecord(): UpdateRecord {
-      const fromCapData = (...args) =>
-        Reflect.apply(marshaller.fromCapData, marshaller, args);
       return unmarshalFromVstorage(
         storage.data,
         `published.wallet.${walletAddress}`,
-        fromCapData,
+        (...args) => Reflect.apply(marshaller.fromCapData, marshaller, args),
         -1,
-      );
+      ) as any;
     },
   });
 
@@ -286,7 +282,7 @@ export const makeGovernanceDriver = async (
   const enactLatestProposal = async () => {
     const latestQuestionRecord = testKit.readLatest(
       'published.committees.Economic_Committee.latestQuestion',
-    );
+    ) as any;
 
     const chosenPositions = [latestQuestionRecord.positions[0]];
 
diff --git a/packages/boot/tools/supports.ts b/packages/boot/tools/supports.ts
index 45ca480db63..3f4d2015348 100644
--- a/packages/boot/tools/supports.ts
+++ b/packages/boot/tools/supports.ts
@@ -283,7 +283,7 @@ export const makeSwingsetTestKit = async (
   const { kernelStorage, hostStorage } = swingStore;
   const { fromCapData } = boardSlottingMarshaller(slotToBoardRemote);
 
-  const readLatest = path => {
+  const readLatest = (path: string): any => {
     const data = unmarshalFromVstorage(storage.data, path, fromCapData, -1);
     trace('readLatest', path, 'returning', inspect(data, false, 20, true));
     return data;
diff --git a/packages/cache/package.json b/packages/cache/package.json
index 18959d176a7..5344052b8e5 100644
--- a/packages/cache/package.json
+++ b/packages/cache/package.json
@@ -47,6 +47,6 @@
     "timeout": "20m"
   },
   "typeCoverage": {
-    "atLeast": 90.97
+    "atLeast": 94.12
   }
 }
diff --git a/packages/cache/src/cache.js b/packages/cache/src/cache.js
index 1788745a74f..19412f78261 100644
--- a/packages/cache/src/cache.js
+++ b/packages/cache/src/cache.js
@@ -4,9 +4,13 @@ import { E, Far } from '@endo/far';
 
 import { makeScalarStoreCoordinator } from './store.js';
 
+/**
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ */
+
 /**
  * @typedef {{ [x: PropertyKey]: any } | string | symbol | bigint | null |
- * undefined | number | ((oldValue: any) => ERef<unknown>)} Update a `newValue`
+ * undefined | number | ((oldValue: any) => ERef<Passable>)} Update a `newValue`
  * to update to.  If a function, then it should take an oldValue and return a
  * `newValue` or promise for `newValue`
  */
@@ -19,7 +23,7 @@ export const makeCache = (coordinator = makeScalarStoreCoordinator()) => {
    * The ground state for a cache key value is `undefined`.  It is impossible to
    * distinguish a set value of `undefined` from an unset key
    *
-   * @param {unknown} key the cache key (any key type acceptable to the cache)
+   * @param {Passable} key the cache key (any key type acceptable to the cache)
    * @param {[] | [Update] | [Update, Pattern]} optUpdateGuardPattern an optional
    */
   const cache = (key, ...optUpdateGuardPattern) => {
diff --git a/packages/cache/src/store.js b/packages/cache/src/store.js
index 1619641d27c..b3700a284e9 100644
--- a/packages/cache/src/store.js
+++ b/packages/cache/src/store.js
@@ -7,7 +7,7 @@ import { withGroundState, makeState } from './state.js';
 /** @import {Passable} from '@endo/pass-style' */
 
 /**
- * @param {(obj: unknown) => unknown} [sanitize]
+ * @param {(obj: Passable) => Passable} [sanitize]
  * @returns {(key: Passable) => Promise<string>}
  */
 const makeKeyToString = (sanitize = obj => obj) => {
@@ -36,16 +36,16 @@ const makeKeyToString = (sanitize = obj => obj) => {
 
 /**
  * @param {string} keyStr
- * @param {(oldValue: unknown) => unknown} txn
+ * @param {(oldValue: Passable) => Passable} txn
  * @param {Pattern} guardPattern
- * @param {(obj: unknown) => unknown} sanitize Process keys and values with
+ * @param {(obj: Passable) => Passable} sanitize Process keys and values with
  * this function before storing them
  * @param {{
  * get(key: string): import('./state.js').State;
  * set(key: string, value: import('./state.js').State): void;
  * init(key: string, value: import('./state.js').State): void;
  * }} stateStore
- * @returns {Promise<unknown>} the value of the updated state
+ * @returns {Promise<Passable>} the value of the updated state
  */
 const applyCacheTransaction = async (
   keyStr,
@@ -112,6 +112,7 @@ const applyCacheTransaction = async (
  * @returns {Promise<string>}
  */
 const stringifyStateStore = async (stateStore, marshaller) => {
+  /** @type {Passable} */
   const obj = {};
   for (const [key, value] of stateStore.entries()) {
     obj[key] = E(marshaller).toCapData(value);
@@ -126,7 +127,7 @@ const stringifyStateStore = async (stateStore, marshaller) => {
  * currently enforce any cache eviction, but that would be a useful feature.
  *
  * @param {MapStore<string, import('./state.js').State>} [stateStore]
- * @param {(obj: unknown) => unknown} [sanitize] Process keys and values with
+ * @param {(obj: Passable) => Passable} [sanitize] Process keys and values with
  * this function before storing them. Defaults to deeplyFulfilled.
  */
 export const makeScalarStoreCoordinator = (
diff --git a/packages/cosmic-swingset/package.json b/packages/cosmic-swingset/package.json
index 0cf750b91bb..bfc78de8b06 100644
--- a/packages/cosmic-swingset/package.json
+++ b/packages/cosmic-swingset/package.json
@@ -68,6 +68,6 @@
     "timeout": "20m"
   },
   "typeCoverage": {
-    "atLeast": 80.49
+    "atLeast": 80.48
   }
 }
diff --git a/packages/deploy-script-support/package.json b/packages/deploy-script-support/package.json
index 323234c9559..54c953bcb65 100644
--- a/packages/deploy-script-support/package.json
+++ b/packages/deploy-script-support/package.json
@@ -73,6 +73,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 81.47
+    "atLeast": 81.63
   }
 }
diff --git a/packages/deploy-script-support/src/offer.js b/packages/deploy-script-support/src/offer.js
index da300ddf9e5..3c03908c865 100644
--- a/packages/deploy-script-support/src/offer.js
+++ b/packages/deploy-script-support/src/offer.js
@@ -19,7 +19,7 @@ import { AmountMath } from '@agoric/ertp/src/amountMath.js';
  * @param {ERef<any>} walletAdmin - an internal type of the
  * wallet, not defined here
  * @param {ERef<ZoeService>} zoe
- * @param {ERef<Purse<'set'>>} zoeInvitationPurse
+ * @param {ERef<Purse<'set', InvitationDetails>>} zoeInvitationPurse
  */
 export const makeOfferAndFindInvitationAmount = (
   walletAdmin,
@@ -28,7 +28,7 @@ export const makeOfferAndFindInvitationAmount = (
 ) => {
   /**
    * @param {Record<string, any>} invitationDetailsCriteria
-   * @returns {Promise<Amount<'set'>>} invitationAmount
+   * @returns {Promise<InvitationAmount>} invitationAmount
    */
   const findInvitationAmount = async invitationDetailsCriteria => {
     const invitationAmount = await E(zoeInvitationPurse).getCurrentAmount();
diff --git a/packages/governance/package.json b/packages/governance/package.json
index 5c9dd06f2a8..3e4bf5514d8 100644
--- a/packages/governance/package.json
+++ b/packages/governance/package.json
@@ -77,6 +77,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 89.25
+    "atLeast": 89.31
   }
 }
diff --git a/packages/governance/src/contractGovernance/governApi.js b/packages/governance/src/contractGovernance/governApi.js
index 386e89e801e..e13debafc73 100644
--- a/packages/governance/src/contractGovernance/governApi.js
+++ b/packages/governance/src/contractGovernance/governApi.js
@@ -10,6 +10,7 @@ import {
 } from '../question.js';
 
 /**
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
  * @import {Position, ApiGovernor, ApiInvocationIssue, PoserFacet, VoteOnApiInvocation} from '../types.js';
  */
 
@@ -21,7 +22,7 @@ const { Fail, quote: q } = assert;
  * arguments that were provided.
  *
  * @param {string} apiMethodName
- * @param {unknown[]} methodArgs
+ * @param {Passable[]} methodArgs
  */
 const makeApiInvocationPositions = (apiMethodName, methodArgs) => {
   const positive = harden({ apiMethodName, methodArgs });
@@ -32,7 +33,7 @@ const makeApiInvocationPositions = (apiMethodName, methodArgs) => {
 /**
  * manage contracts that allow governance to invoke functions.
  *
- * @param {ERef<{ [methodName: string]: (...args: any) => unknown }>} governedApis
+ * @param {ERef<{ [methodName: string]: (...args: any) => Passable }>} governedApis
  * @param {Array<string | symbol>} governedNames names of the governed API methods
  * @param {ERef<import('@agoric/time').TimerService>} timer
  * @param {() => Promise<PoserFacet>} getUpdatedPoserFacet
diff --git a/packages/governance/src/contractGovernance/governParam.js b/packages/governance/src/contractGovernance/governParam.js
index f06c7d4bb19..789a441d32a 100644
--- a/packages/governance/src/contractGovernance/governParam.js
+++ b/packages/governance/src/contractGovernance/governParam.js
@@ -78,6 +78,7 @@ const setupParamGovernance = (
     paramSpec,
   ) => {
     const paramMgr = await E(paramManagerRetriever).get(paramSpec.paramPath);
+    /** @type {import('@endo/marshal').Passable} */
     const changePs = {};
     for (const name of Object.keys(paramSpec.changes)) {
       const proposedValue = E(paramMgr).getVisibleValue(
diff --git a/packages/governance/src/contractGovernance/paramManager.js b/packages/governance/src/contractGovernance/paramManager.js
index ed96f7cb3df..b9cca051cb5 100644
--- a/packages/governance/src/contractGovernance/paramManager.js
+++ b/packages/governance/src/contractGovernance/paramManager.js
@@ -49,7 +49,7 @@ const assertElectorateMatches = (paramManager, governedParams) => {
  * @property {(name: string, value: Invitation) => ParamManagerBuilder} addInvitation
  * @property {(name: string, value: bigint) => ParamManagerBuilder} addNat
  * @property {(name: string, value: Ratio) => ParamManagerBuilder} addRatio
- * @property {(name: string, value: import('@endo/marshal').CopyRecord<unknown>) => ParamManagerBuilder} addRecord
+ * @property {(name: string, value: import('@endo/marshal').CopyRecord<any>) => ParamManagerBuilder} addRecord
  * @property {(name: string, value: string) => ParamManagerBuilder} addString
  * @property {(name: string, value: import('@agoric/time').Timestamp) => ParamManagerBuilder} addTimestamp
  * @property {(name: string, value: import('@agoric/time').RelativeTime) => ParamManagerBuilder} addRelativeTime
@@ -184,7 +184,7 @@ const makeParamManagerBuilder = (publisherKit, zoe) => {
     return builder;
   };
 
-  /** @type {(name: string, value: import('@endo/marshal').CopyRecord<unknown>, builder: ParamManagerBuilder) => ParamManagerBuilder} */
+  /** @type {(name: string, value: import('@endo/marshal').CopyRecord, builder: ParamManagerBuilder) => ParamManagerBuilder} */
   const addRecord = (name, value, builder) => {
     const assertRecord = v => {
       passStyleOf(v);
diff --git a/packages/governance/src/contractGovernorKit.js b/packages/governance/src/contractGovernorKit.js
index 3bdf7e7bf6a..b7b6abe8e5b 100644
--- a/packages/governance/src/contractGovernorKit.js
+++ b/packages/governance/src/contractGovernorKit.js
@@ -129,7 +129,8 @@ export const prepareContractGovernorKit = (baggage, powers) => {
             ]);
             trace('setupApiGovernance');
             apiGovernance = governedNames.length
-              ? setupApiGovernance(governedApis, governedNames, timer, () =>
+              ? // @ts-expect-error FIXME
+                setupApiGovernance(governedApis, governedNames, timer, () =>
                   this.facets.helper.getUpdatedPoserFacet(),
                 )
               : {
diff --git a/packages/governance/src/types.js b/packages/governance/src/types.js
index 23c8e3ddec7..c47b567dc0d 100644
--- a/packages/governance/src/types.js
+++ b/packages/governance/src/types.js
@@ -1,6 +1,10 @@
 export {};
 
-/** @import {ContractStartFunction} from '@agoric/zoe/src/zoeService/utils.js' */
+/**
+ * @import {Guarded} from '@endo/exo';
+ * @import {Passable, Container} from '@endo/pass-style';
+ * @import {ContractStartFunction} from '@agoric/zoe/src/zoeService/utils.js';
+ */
 
 /**
  * @typedef { 'unranked' | 'order' | 'plurality' } ChoiceMethod
@@ -34,9 +38,9 @@ export {};
  */
 
 /**
- * @typedef { Amount | Brand | Installation | Instance | bigint |
+ * @typedef { Amount | Brand | Installation | Instance | number | bigint |
  *   Ratio | string | import('@agoric/time').TimestampRecord |
- *   import('@agoric/time').RelativeTimeRecord | unknown } ParamValue
+ *   import('@agoric/time').RelativeTimeRecord | Container<any, any> } ParamValue
  */
 
 // XXX better to use the manifest constant ParamTypes
@@ -61,7 +65,7 @@ export {};
 
 /**
  * @template {ParamType} [T=ParamType]
- * @typedef {{ type: T, value: ParamValueForType<T> }} ParamValueTyped<T>
+ * @typedef {{ type: T, value: ParamValueForType<T> }} ParamValueTyped
  */
 
 /**
@@ -73,7 +77,7 @@ export {};
  *   governedParams: import('./contractGovernance/typedParamManager.js').ParamRecordsFromTypes<T & {
  *     Electorate: 'invitation'
  *   }>
- * }} GovernanceTerms<T>
+ * }} GovernanceTerms
  */
 
 /**
@@ -430,7 +434,7 @@ export {};
  * @property {(name: string) => Brand} getBrand
  * @property {(name: string) => Instance} getInstance
  * @property {(name: string) => Installation} getInstallation
- * @property {(name: string) => Amount<'set'>} getInvitationAmount
+ * @property {(name: string) => InvitationAmount} getInvitationAmount
  * @property {(name: string) => bigint} getNat
  * @property {(name: string) => Ratio} getRatio
  * @property {(name: string) => string} getString
@@ -484,7 +488,7 @@ export {};
 
 /**
  * @typedef {object} ChangeParamsPosition
- * @property {Record<string,ParamValue>} changes one or more changes to parameters
+ * @property {Record<string, ParamValue>} changes one or more changes to parameters
  */
 
 /**
@@ -500,7 +504,7 @@ export {};
 /**
  * @typedef {object} InvokeApiPosition
  * @property {string} apiMethodName
- * @property {unknown[]} methodArgs
+ * @property {Passable[]} methodArgs
  */
 
 /**
@@ -625,7 +629,7 @@ export {};
 /**
  * @callback VoteOnApiInvocation
  * @param {string} apiMethodName
- * @param {unknown[]} methodArgs
+ * @param {Passable[]} methodArgs
  * @param {Installation} voteCounterInstallation
  * @param {import('@agoric/time').Timestamp} deadline
  * @returns {Promise<ContractGovernanceVoteResult>}
@@ -727,7 +731,7 @@ export {};
  * Akin to StartedInstanceKit but designed for the results of starting governed contracts. Used in bootstrap space.
  * @property {AdminFacet} adminFacet of the governed contract
  * @property {LimitedCF<SF>} creatorFacet creator-like facet within the governed contract (without the powers the governor needs)
- * @property {GovernorCreatorFacet<SF>} governorCreatorFacet of the governing contract
+ * @property {Guarded<GovernorCreatorFacet<SF>>} governorCreatorFacet of the governing contract
  * @property {AdminFacet} governorAdminFacet of the governing contract
  * @property {Awaited<ReturnType<SF>>['publicFacet']} publicFacet
  * @property {Instance} instance
diff --git a/packages/governance/test/unitTests/test-typedParamManager.js b/packages/governance/test/unitTests/test-typedParamManager.js
index 505d826acfa..a4ef53487db 100644
--- a/packages/governance/test/unitTests/test-typedParamManager.js
+++ b/packages/governance/test/unitTests/test-typedParamManager.js
@@ -228,6 +228,7 @@ test('Invitation', async t => {
 
   const { instance, zcf, zoe } = await setupZCFTest(issuerKeywordRecord, terms);
 
+  /** @type {Invitation} */
   const invitation = await E(E(zoe).getPublicFacet(instance)).makeInvitation();
 
   const invitationAmount = await E(E(zoe).getInvitationIssuer()).getAmountOf(
@@ -251,6 +252,7 @@ test('Invitation', async t => {
   await eventLoopIteration();
   const invitationActualAmount = paramManager.getInvite().value;
   t.deepEqual(invitationActualAmount, invitationAmount.value);
+  // @ts-expect-error XXX
   t.is(invitationActualAmount[0].description, 'simple');
 
   t.is(await paramManager.getInternalParamValue('Invite'), invitation);
diff --git a/packages/governance/tools/puppetContractGovernor.js b/packages/governance/tools/puppetContractGovernor.js
index 3f6db072a1d..d4edd79883b 100644
--- a/packages/governance/tools/puppetContractGovernor.js
+++ b/packages/governance/tools/puppetContractGovernor.js
@@ -7,6 +7,7 @@ import { CONTRACT_ELECTORATE } from '../src/contractGovernance/governParam.js';
 import { makeApiInvocationPositions } from '../src/contractGovernance/governApi.js';
 
 /**
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
  * @import {GovernableStartFn, ParamChangesSpec} from '../src/types.js';
  */
 
@@ -72,7 +73,7 @@ export const start = async (zcf, privateArgs) => {
 
   /**
    * @param {string} apiMethodName
-   * @param {unknown[]} methodArgs
+   * @param {Passable[]} methodArgs
    */
   const invokeAPI = async (apiMethodName, methodArgs) => {
     const governedNames = await E(governedCF).getGovernedApiNames();
diff --git a/packages/inter-protocol/package.json b/packages/inter-protocol/package.json
index ed07d754e13..86f24840e08 100644
--- a/packages/inter-protocol/package.json
+++ b/packages/inter-protocol/package.json
@@ -83,6 +83,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 95.89
+    "atLeast": 95.86
   }
 }
diff --git a/packages/inter-protocol/src/auction/auctioneer.js b/packages/inter-protocol/src/auction/auctioneer.js
index 8807b00f5a1..88ace013d94 100644
--- a/packages/inter-protocol/src/auction/auctioneer.js
+++ b/packages/inter-protocol/src/auction/auctioneer.js
@@ -693,7 +693,7 @@ export const start = async (zcf, privateArgs, baggage) => {
   const creatorFacet = makeFarGovernorFacet(
     Far('Auctioneer creatorFacet', {
       /**
-       * @param {Issuer} issuer
+       * @param {Issuer<'nat'>} issuer
        * @param {Keyword} kwd
        */
       async addBrand(issuer, kwd) {
diff --git a/packages/inter-protocol/src/auction/sortedOffers.js b/packages/inter-protocol/src/auction/sortedOffers.js
index 031c73e3ebe..f1d0e211d49 100644
--- a/packages/inter-protocol/src/auction/sortedOffers.js
+++ b/packages/inter-protocol/src/auction/sortedOffers.js
@@ -88,6 +88,7 @@ const bidScalingRatioFromKey = (bidScaleFloat, numBrand, useDecimals) => {
  * @returns {[normalizedPrice: Ratio, sequenceNumber: bigint]}
  */
 export const fromPriceOfferKey = (key, numBrand, denomBrand, useDecimals) => {
+  // @ts-expect-error XXX
   const [pricePart, sequenceNumberPart] = decodeData(key);
   return [
     priceRatioFromFloat(pricePart, numBrand, denomBrand, useDecimals),
diff --git a/packages/inter-protocol/src/contractSupport.js b/packages/inter-protocol/src/contractSupport.js
index 1aec13135a9..3226ce8fddf 100644
--- a/packages/inter-protocol/src/contractSupport.js
+++ b/packages/inter-protocol/src/contractSupport.js
@@ -21,11 +21,11 @@ export const ratioPattern = harden({
  * proposal. We use two Amounts because an Amount cannot represent a negative
  * number (so we use a "loss" that will be subtracted).
  *
- * @template {AssetKind} K
- * @param {Amount<K>} base
- * @param {Amount<K>} gain
- * @param {Amount<K>} loss
- * @returns {Amount<K>}
+ * @template {Amount} A
+ * @param {A} base
+ * @param {A} gain
+ * @param {A} loss
+ * @returns {A}
  */
 export const addSubtract = (base, gain, loss) =>
   AmountMath.subtract(AmountMath.add(base, gain), loss);
@@ -79,14 +79,14 @@ export const checkDebtLimit = (debtLimit, totalDebt, toMint) => {
 
 /**
  * @template T
- * @typedef {object} MetricsPublisherKit<T>
+ * @typedef {object} MetricsPublisherKit
  * @property {IterationObserver<T>} metricsPublication
  * @property {StoredSubscription<T>} metricsSubscription
  */
 
 /**
  * @template T
- * @typedef {object} MetricsPublishKit<T>
+ * @typedef {object} MetricsPublishKit
  * @property {Publisher<T>} metricsPublisher
  * @property {StoredSubscriber<T>} metricsSubscriber
  */
diff --git a/packages/inter-protocol/src/econCommitteeCharter.js b/packages/inter-protocol/src/econCommitteeCharter.js
index e0ff7192393..6fc146cb167 100644
--- a/packages/inter-protocol/src/econCommitteeCharter.js
+++ b/packages/inter-protocol/src/econCommitteeCharter.js
@@ -79,6 +79,7 @@ export const start = async (zcf, privateArgs, baggage) => {
       const governor = instanceToGovernor.get(instance);
       return E(governor).voteOnParamChanges(counter, deadline, {
         ...path,
+        // @ts-expect-error XXX
         changes: params,
       });
     };
diff --git a/packages/inter-protocol/src/price/fluxAggregatorContract.js b/packages/inter-protocol/src/price/fluxAggregatorContract.js
index 3f06800d3e7..0eb968edd2b 100644
--- a/packages/inter-protocol/src/price/fluxAggregatorContract.js
+++ b/packages/inter-protocol/src/price/fluxAggregatorContract.js
@@ -67,6 +67,7 @@ export const start = async (zcf, privateArgs, baggage) => {
 
   // xxx uses contract baggage as issuerBagage, assumes one issuer in this contract
   /** @type {import('./roundsManager.js').QuoteKit} */
+  // @ts-expect-error cast
   const quoteIssuerKit = prepareIssuerKit(
     baggage,
     'quote',
diff --git a/packages/inter-protocol/src/price/roundsManager.js b/packages/inter-protocol/src/price/roundsManager.js
index 2d4c1256824..f9436c7b77f 100644
--- a/packages/inter-protocol/src/price/roundsManager.js
+++ b/packages/inter-protocol/src/price/roundsManager.js
@@ -62,7 +62,7 @@ const validRoundId = roundId => {
  * @property {number} roundTimeout
  */
 
-/** @typedef {IssuerKit<'set'>} QuoteKit */
+/** @typedef {IssuerKit<'set', PriceDescription>} QuoteKit */
 
 /**
  * @typedef {Readonly<
diff --git a/packages/inter-protocol/src/proposals/add-auction.js b/packages/inter-protocol/src/proposals/add-auction.js
index 1eafb2e747f..7616e8aac56 100644
--- a/packages/inter-protocol/src/proposals/add-auction.js
+++ b/packages/inter-protocol/src/proposals/add-auction.js
@@ -121,11 +121,15 @@ export const addAuction = async ({
   const { Bid: _istIssuer, ...auctionIssuers } = allIssuers;
   await Promise.all(
     Object.keys(auctionIssuers).map(kwd =>
-      E(governedCreatorFacet).addBrand(auctionIssuers[kwd], kwd),
+      E(governedCreatorFacet).addBrand(
+        /** @type {Issuer<'nat'>} */ (auctionIssuers[kwd]),
+        kwd,
+      ),
     ),
   );
 
   newAuctioneerKit.resolve(
+    // @ts-expect-error XXX governance types
     harden({
       label: 'auctioneer',
       creatorFacet: governedCreatorFacet,
diff --git a/packages/inter-protocol/src/proposals/core-proposal.js b/packages/inter-protocol/src/proposals/core-proposal.js
index 11c476629e9..ba31357f616 100644
--- a/packages/inter-protocol/src/proposals/core-proposal.js
+++ b/packages/inter-protocol/src/proposals/core-proposal.js
@@ -27,7 +27,7 @@ export const storeInterContractStartKits = async ({
   },
 }) => {
   /**
-   * @param {Promise<MapStore<string, { instance: Instance }>>} storeP
+   * @param {Promise<MapStore<Instance, { instance: Instance }>>} storeP
    * @param {Promise<{ instance: Instance }>[]} kitPs
    */
   const storeAll = async (storeP, kitPs) => {
diff --git a/packages/inter-protocol/src/proposals/econ-behaviors.js b/packages/inter-protocol/src/proposals/econ-behaviors.js
index c5fec37281f..c3fbff712bd 100644
--- a/packages/inter-protocol/src/proposals/econ-behaviors.js
+++ b/packages/inter-protocol/src/proposals/econ-behaviors.js
@@ -166,6 +166,7 @@ export const setupReserve = async ({
   ]);
 
   reserveKit.resolve(
+    // @ts-expect-error XXX
     harden({
       label: 'AssetReserve',
       instance,
@@ -350,6 +351,7 @@ export const startVaultFactory = async (
   );
 
   vaultFactoryKit.resolve(
+    // @ts-expect-error XXX
     harden({
       label: 'VaultFactory',
       creatorFacet: vaultFactoryCreator,
@@ -465,6 +467,7 @@ export const startRewardDistributor = async ({
   const instanceKit = await E(zoe).startInstance(
     feeDistributor,
     { Fee: centralIssuer },
+    // @ts-expect-error XXX
     feeDistributorTerms,
     undefined,
     'feeDistributor',
@@ -623,6 +626,7 @@ export const startAuctioneer = async (
     ]);
 
   auctioneerKit.resolve(
+    // @ts-expect-error XXX
     harden({
       label: 'auctioneer',
       creatorFacet: governedCreatorFacet,
diff --git a/packages/inter-protocol/src/proposals/startPSM.js b/packages/inter-protocol/src/proposals/startPSM.js
index a13e38efc0f..121813acf99 100644
--- a/packages/inter-protocol/src/proposals/startPSM.js
+++ b/packages/inter-protocol/src/proposals/startPSM.js
@@ -363,6 +363,7 @@ export const makeAnchorAsset = async (
   const brand = await E(issuer).getBrand();
   const kit = harden({ mint, issuer, brand });
 
+  // @ts-expect-error XXX AssetIssuerKit
   testFirstAnchorKit.resolve(kit);
 
   const toSlotReviver = makeHistoryReviver(
@@ -397,6 +398,7 @@ export const makeAnchorAsset = async (
       denom,
       keyword,
       proposedName,
+      // @ts-expect-error XXX AssetIssuerKit
       kit, // with mint
     ),
   ]);
diff --git a/packages/inter-protocol/src/provisionPool.js b/packages/inter-protocol/src/provisionPool.js
index 27a7622cf64..7eb37c61dd1 100644
--- a/packages/inter-protocol/src/provisionPool.js
+++ b/packages/inter-protocol/src/provisionPool.js
@@ -14,6 +14,8 @@ import { prepareRecorderKitMakers } from '@agoric/zoe/src/contractSupport/record
 import { TopicsRecordShape } from '@agoric/zoe/src/contractSupport/topics.js';
 import { prepareProvisionPoolKit } from './provisionPoolKit.js';
 
+/** @import {Marshal} from '@endo/marshal'; */
+
 /** @type {ContractMeta} */
 export const meta = {
   privateArgsShape: M.splitRecord(
@@ -45,7 +47,7 @@ harden(meta);
  *   >;
  *   initialPoserInvitation: Invitation;
  *   storageNode: StorageNode;
- *   marshaller: Marshaller;
+ *   marshaller: Marshal<any>;
  *   metricsOverride?: import('./provisionPoolKit.js').MetricsNotification;
  * }} privateArgs
  * @param {import('@agoric/vat-data').Baggage} baggage
@@ -84,6 +86,7 @@ export const start = async (zcf, privateArgs, baggage) => {
       makeProvisionPoolKit({
         // XXX governance can change the brand of the amount but should only be able to change the value
         // NB: changing the brand will break this pool
+        // @ts-expect-error XXX Brand AssetKind
         poolBrand: params.getPerAccountInitialAmount().brand,
         storageNode: privateArgs.storageNode,
       }),
diff --git a/packages/inter-protocol/src/provisionPoolKit.js b/packages/inter-protocol/src/provisionPoolKit.js
index 179c562b281..cd87e8571df 100644
--- a/packages/inter-protocol/src/provisionPoolKit.js
+++ b/packages/inter-protocol/src/provisionPoolKit.js
@@ -1,5 +1,6 @@
 // @ts-check
 import { AmountMath, BrandShape } from '@agoric/ertp';
+import { deeplyFulfilledObject } from '@agoric/internal';
 import { UnguardedHelperI } from '@agoric/internal/src/typeGuards.js';
 import {
   observeIteration,
@@ -19,7 +20,7 @@ import {
 } from '@agoric/zoe/src/contractSupport/topics.js';
 import { InstanceHandleShape } from '@agoric/zoe/src/typeGuards.js';
 import { E } from '@endo/far';
-import { Far, deeplyFulfilled } from '@endo/marshal';
+import { Far } from '@endo/marshal';
 
 const { details: X, quote: q, Fail } = assert;
 
@@ -197,7 +198,7 @@ export const prepareProvisionPoolKit = (
             namesByAddressAdmin,
             walletFactory,
           });
-          const refs = await deeplyFulfilled(obj);
+          const refs = await deeplyFulfilledObject(obj);
           Object.assign(this.state, refs);
         },
         makeHandler() {
@@ -347,7 +348,6 @@ export const prepareProvisionPoolKit = (
                 console.log('provisionPool notified of new asset', desc.brand);
                 await zcf.saveIssuer(desc.issuer, desc.issuerName);
                 /** @type {ERef<Purse>} */
-                // @ts-expect-error vbank purse is close enough for our use.
                 const exchangePurse = E(poolBank).getPurse(desc.brand);
                 void observeNotifier(
                   E(exchangePurse).getCurrentAmountNotifier(),
diff --git a/packages/inter-protocol/src/vaultFactory/vault.js b/packages/inter-protocol/src/vaultFactory/vault.js
index 17ee452ccc7..4a36efccfc3 100644
--- a/packages/inter-protocol/src/vaultFactory/vault.js
+++ b/packages/inter-protocol/src/vaultFactory/vault.js
@@ -20,7 +20,10 @@ const { quote: q, Fail } = assert;
 
 const trace = makeTracer('Vault', true);
 
-/** @import {NormalizedDebt} from './storeUtils.js' */
+/**
+ * @import {Brand} from '@agoric/ertp/src/types.js';
+ * @import {NormalizedDebt} from './storeUtils.js';
+ */
 
 /**
  * @file This has most of the logic for a Vault, to borrow Minted against
@@ -301,13 +304,20 @@ export const prepareVault = (baggage, makeRecorderKit, zcf) => {
           );
         },
 
-        /** @param {ZCFSeat} seat */
+        /**
+         * @param {ZCFSeat} seat
+         * @returns {Amount<'nat'>}
+         */
         getCollateralAllocated(seat) {
           return seat.getAmountAllocated(
             'Collateral',
             this.facets.helper.collateralBrand(),
           );
         },
+        /**
+         * @param {ZCFSeat} seat
+         * @returns {Amount<'nat'>}
+         */
         getMintedAllocated(seat) {
           return seat.getAmountAllocated(
             'Minted',
diff --git a/packages/inter-protocol/src/vaultFactory/vaultHolder.js b/packages/inter-protocol/src/vaultFactory/vaultHolder.js
index 9552d27857f..c4a4acd49b7 100644
--- a/packages/inter-protocol/src/vaultFactory/vaultHolder.js
+++ b/packages/inter-protocol/src/vaultFactory/vaultHolder.js
@@ -52,6 +52,7 @@ export const prepareVaultHolder = (baggage, makeRecorderKit) => {
      */
     (vault, storageNode) => {
       // must be the fully synchronous maker because the kit is held in durable state
+      // @ts-expect-error XXX Patterns
       const topicKit = makeRecorderKit(storageNode, PUBLIC_TOPICS.vault[1]);
 
       return { topicKit, vault };
diff --git a/packages/inter-protocol/src/vaultFactory/vaultManager.js b/packages/inter-protocol/src/vaultFactory/vaultManager.js
index fbbde1eb542..c3f74b98bb0 100644
--- a/packages/inter-protocol/src/vaultFactory/vaultManager.js
+++ b/packages/inter-protocol/src/vaultFactory/vaultManager.js
@@ -439,7 +439,9 @@ export const prepareVaultManagerKit = (
             collateralUnit,
             debtBrand,
           );
+          // @ts-expect-error XXX quotes
           ephemera.storedQuotesNotifier = makeStoredNotifier(
+            // @ts-expect-error XXX quotes
             quoteNotifier,
             E(storageNode).makeChildNode('quotes'),
             marshaller,
diff --git a/packages/inter-protocol/test/smartWallet/test-psm-integration.js b/packages/inter-protocol/test/smartWallet/test-psm-integration.js
index 8aa62f3ae10..65450049c10 100644
--- a/packages/inter-protocol/test/smartWallet/test-psm-integration.js
+++ b/packages/inter-protocol/test/smartWallet/test-psm-integration.js
@@ -245,7 +245,7 @@ test('govern offerFilter', async t => {
           invitationBrand,
           'invitation brand from context matches zoe',
         );
-        /** @type {Amount<'set'>} */
+        /** @type {InvitationAmount} */
         const invitationsAmount = NonNullish(balances.get(brand));
         t.is(invitationsAmount?.value.length, len, 'invitation count');
         return invitationsAmount.value.filter(i => i.description === desc);
diff --git a/packages/inter-protocol/test/swingsetTests/psmUpgrade/bootstrap-psm-upgrade.js b/packages/inter-protocol/test/swingsetTests/psmUpgrade/bootstrap-psm-upgrade.js
index e3a2d4c9e87..3cb5c471c3d 100644
--- a/packages/inter-protocol/test/swingsetTests/psmUpgrade/bootstrap-psm-upgrade.js
+++ b/packages/inter-protocol/test/swingsetTests/psmUpgrade/bootstrap-psm-upgrade.js
@@ -131,6 +131,7 @@ export const buildRootObject = async () => {
      * @param {any} devices
      */
     bootstrap: async (vats, devices) => {
+      // @ts-expect-error XXX adminNode
       vatAdmin = await E(vats.vatAdmin).createVatAdminService(devices.vatAdmin);
       ({ feeMintAccess, zoeService } = await E(vats.zoe).buildZoe(
         vatAdmin,
@@ -215,6 +216,7 @@ export const buildRootObject = async () => {
       governorFacets = await E(zoeService).startInstance(
         NonNullish(installations.puppetContractGovernor),
         undefined,
+        // @ts-expect-error XXX timer
         governorTerms,
         {
           governed: {
diff --git a/packages/inter-protocol/test/swingsetTests/reserve/bootstrap-assetReserve-upgrade.js b/packages/inter-protocol/test/swingsetTests/reserve/bootstrap-assetReserve-upgrade.js
index c6f00c8655a..fce40bbd820 100644
--- a/packages/inter-protocol/test/swingsetTests/reserve/bootstrap-assetReserve-upgrade.js
+++ b/packages/inter-protocol/test/swingsetTests/reserve/bootstrap-assetReserve-upgrade.js
@@ -188,6 +188,7 @@ export const buildRootObject = async () => {
       governorFacets = await E(zoeService).startInstance(
         NonNullish(installations.puppetContractGovernor),
         undefined,
+        // @ts-expect-error XXX timer
         governorTerms,
         {
           governed: {
diff --git a/packages/inter-protocol/test/vaultFactory/test-replacePriceAuthority.js b/packages/inter-protocol/test/vaultFactory/test-replacePriceAuthority.js
index f442a781808..53f04b6bbfc 100644
--- a/packages/inter-protocol/test/vaultFactory/test-replacePriceAuthority.js
+++ b/packages/inter-protocol/test/vaultFactory/test-replacePriceAuthority.js
@@ -2,13 +2,17 @@ import '@agoric/zoe/exported.js';
 import { test as unknownTest } from '@agoric/zoe/tools/prepare-test-env-ava.js';
 
 import { AmountMath, makeIssuerKit } from '@agoric/ertp';
-import { allValues, makeTracer, objectMap } from '@agoric/internal';
+import {
+  allValues,
+  deeplyFulfilledObject,
+  makeTracer,
+  objectMap,
+} from '@agoric/internal';
 import { unsafeMakeBundleCache } from '@agoric/swingset-vat/tools/bundleTool.js';
 import { makeRatio } from '@agoric/zoe/src/contractSupport/index.js';
 import { eventLoopIteration } from '@agoric/internal/src/testing-utils.js';
 import { buildManualTimer } from '@agoric/swingset-vat/tools/manual-timer.js';
 import { E } from '@endo/eventual-send';
-import { deeplyFulfilled } from '@endo/marshal';
 import { TimeMath } from '@agoric/time';
 import { providePriceAuthorityRegistry } from '@agoric/vats/src/priceAuthorityRegistry.js';
 import { makeScalarMapStore } from '@agoric/vat-data/src/index.js';
@@ -107,11 +111,13 @@ test.before(async t => {
     referencedUi: undefined,
     rates: defaultParamValues(run.brand),
   };
-  const frozenCtx = await deeplyFulfilled(harden(contextPs));
+  const frozenCtx = await deeplyFulfilledObject(harden(contextPs));
   t.context = {
     ...frozenCtx,
     bundleCache,
+    // @ts-expect-error XXX AssetIssuerKit
     aeth,
+    // @ts-expect-error XXX AssetIssuerKit
     run,
   };
   trace(t, 'CONTEXT');
diff --git a/packages/inter-protocol/test/vaultFactory/test-storage.js b/packages/inter-protocol/test/vaultFactory/test-storage.js
index 0235c60d91c..a5f579afeaf 100644
--- a/packages/inter-protocol/test/vaultFactory/test-storage.js
+++ b/packages/inter-protocol/test/vaultFactory/test-storage.js
@@ -147,7 +147,6 @@ test('quotes storage', async t => {
     quoteValue.amountIn.value,
     quoteValue.amountOut.value / quoteValue.amountIn.value,
   );
-  // @ts-expect-error thinks the left argument is Number
   t.is(quoteValue.amountOut.value / quoteValue.amountIn.value, highPrice);
 });
 
diff --git a/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js b/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js
index 5ab027d7a21..6852667f737 100644
--- a/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js
+++ b/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js
@@ -3,7 +3,12 @@ import { test as unknownTest } from '@agoric/zoe/tools/prepare-test-env-ava.js';
 
 import { AmountMath, AssetKind, makeIssuerKit } from '@agoric/ertp';
 import { combine, split } from '@agoric/ertp/src/legacy-payment-helpers.js';
-import { allValues, makeTracer, objectMap } from '@agoric/internal';
+import {
+  allValues,
+  deeplyFulfilledObject,
+  makeTracer,
+  objectMap,
+} from '@agoric/internal';
 import { eventLoopIteration } from '@agoric/internal/src/testing-utils.js';
 import { makeNotifierFromAsyncIterable } from '@agoric/notifier';
 import { M, matches } from '@agoric/store';
@@ -21,7 +26,6 @@ import { makeManualPriceAuthority } from '@agoric/zoe/tools/manualPriceAuthority
 import { documentStorageSchema } from '@agoric/governance/tools/storageDoc.js';
 import buildManualTimer from '@agoric/zoe/tools/manualTimer.js';
 import { E } from '@endo/eventual-send';
-import { deeplyFulfilled } from '@endo/marshal';
 import { calculateCurrentDebt } from '../../src/interest-math.js';
 import { SECONDS_PER_YEAR } from '../../src/interest.js';
 import { startVaultFactory } from '../../src/proposals/econ-behaviors.js';
@@ -116,11 +120,13 @@ test.before(async t => {
     referencedUi: undefined,
     rates: defaultParamValues(run.brand),
   };
-  const frozenCtx = await deeplyFulfilled(harden(contextPs));
+  const frozenCtx = await deeplyFulfilledObject(harden(contextPs));
   t.context = {
     ...frozenCtx,
     bundleCache,
+    // @ts-expect-error XXX AssetIssuerKit
     aeth,
+    // @ts-expect-error XXX AssetIssuerKit
     run,
   };
   trace(t, 'CONTEXT');
diff --git a/packages/inter-protocol/test/vaultFactory/test-vaultLiquidation.js b/packages/inter-protocol/test/vaultFactory/test-vaultLiquidation.js
index 16423355617..45cf37a1bf8 100644
--- a/packages/inter-protocol/test/vaultFactory/test-vaultLiquidation.js
+++ b/packages/inter-protocol/test/vaultFactory/test-vaultLiquidation.js
@@ -2,7 +2,12 @@ import '@agoric/zoe/exported.js';
 import { test as unknownTest } from '@agoric/zoe/tools/prepare-test-env-ava.js';
 
 import { AmountMath, makeIssuerKit } from '@agoric/ertp';
-import { allValues, makeTracer, objectMap } from '@agoric/internal';
+import {
+  allValues,
+  deeplyFulfilledObject,
+  makeTracer,
+  objectMap,
+} from '@agoric/internal';
 import { unsafeMakeBundleCache } from '@agoric/swingset-vat/tools/bundleTool.js';
 import {
   ceilMultiplyBy,
@@ -12,7 +17,6 @@ import {
 import { eventLoopIteration } from '@agoric/internal/src/testing-utils.js';
 import { buildManualTimer } from '@agoric/swingset-vat/tools/manual-timer.js';
 import { E } from '@endo/eventual-send';
-import { deeplyFulfilled } from '@endo/marshal';
 import { TimeMath } from '@agoric/time';
 import { assertPayoutAmount } from '@agoric/zoe/test/zoeTestHelpers.js';
 import { multiplyBy } from '@agoric/zoe/src/contractSupport/ratio.js';
@@ -112,11 +116,13 @@ test.before(async t => {
     referencedUi: undefined,
     rates: defaultParamValues(run.brand),
   };
-  const frozenCtx = await deeplyFulfilled(harden(contextPs));
+  const frozenCtx = await deeplyFulfilledObject(harden(contextPs));
   t.context = {
     ...frozenCtx,
     bundleCache,
+    // @ts-expect-error XXX AssetIssuerKit
     aeth,
+    // @ts-expect-error XXX AssetIssuerKit
     run,
   };
   trace(t, 'CONTEXT');
diff --git a/packages/internal/package.json b/packages/internal/package.json
index b07150362f0..4801037dd49 100755
--- a/packages/internal/package.json
+++ b/packages/internal/package.json
@@ -53,6 +53,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 93.01
+    "atLeast": 93.81
   }
 }
diff --git a/packages/internal/src/lib-chainStorage.js b/packages/internal/src/lib-chainStorage.js
index 2591b1370c0..984a72c576e 100644
--- a/packages/internal/src/lib-chainStorage.js
+++ b/packages/internal/src/lib-chainStorage.js
@@ -5,7 +5,10 @@ import { M } from '@endo/patterns';
 import { makeHeapZone } from '@agoric/base-zone/heap.js';
 import * as cb from './callback.js';
 
-/** @import { ERef } from '@endo/far' */
+/**
+ * @import {ERef} from '@endo/far';
+ * @import {PassableCap} from '@endo/marshal';
+ */
 
 const { Fail } = assert;
 
@@ -265,7 +268,7 @@ harden(makeStorageNodeChild);
 /**
  * @param {ERef<StorageNode>} storageNode
  * @param {ERef<Marshaller>} marshaller
- * @returns {(value: unknown) => Promise<void>}
+ * @returns {(value: PassableCap) => Promise<void>}
  */
 export const makeSerializeToStorage = (storageNode, marshaller) => {
   return async value => {
diff --git a/packages/internal/src/marshal.js b/packages/internal/src/marshal.js
index fadbfc5d535..a167cf0ea83 100644
--- a/packages/internal/src/marshal.js
+++ b/packages/internal/src/marshal.js
@@ -72,6 +72,7 @@ harden(assertCapData);
  * @param {string} key
  * @param {ReturnType<typeof import('@endo/marshal').makeMarshal>['fromCapData']} fromCapData
  * @param {number} index index of the desired value in a deserialized stream cell
+ * @return {any}
  */
 export const unmarshalFromVstorage = (data, key, fromCapData, index) => {
   const serialized = data.get(key) || Fail`no data for ${key}`;
diff --git a/packages/internal/src/storage-test-utils.js b/packages/internal/src/storage-test-utils.js
index 3a344e55649..c8765fc3c60 100644
--- a/packages/internal/src/storage-test-utils.js
+++ b/packages/internal/src/storage-test-utils.js
@@ -6,6 +6,10 @@ import { makeTracer } from './debug.js';
 import { isStreamCell, makeChainStorageRoot } from './lib-chainStorage.js';
 import { bindAllMethods } from './method-tools.js';
 
+/**
+ * @import {Marshaller, StorageEntry, StorageMessage, StorageNode} from './lib-chainStorage.js';
+ */
+
 const { Fail } = assert;
 
 const trace = makeTracer('StorTU', false);
@@ -113,9 +117,9 @@ export const makeFakeStorageKit = (rootPath, rootOptions) => {
     }
     return childEntries;
   };
-  /** @type {import('../src/lib-chainStorage.js').StorageMessage[]} */
+  /** @type {StorageMessage[]} */
   const messages = [];
-  /** @param {import('../src/lib-chainStorage.js').StorageMessage} message */
+  /** @param {StorageMessage} message */
 
   const toStorage = message => {
     messages.push(message);
@@ -143,7 +147,7 @@ export const makeFakeStorageKit = (rootPath, rootOptions) => {
       case 'set':
       case 'setWithoutNotify': {
         trace('toStorage set', message);
-        /** @type {import('../src/lib-chainStorage.js').StorageEntry[]} */
+        /** @type {StorageEntry[]} */
         const newEntries = message.args;
         for (const [key, value] of newEntries) {
           if (value != null) {
@@ -156,7 +160,7 @@ export const makeFakeStorageKit = (rootPath, rootOptions) => {
       }
       case 'append': {
         trace('toStorage append', message);
-        /** @type {import('../src/lib-chainStorage.js').StorageEntry[]} */
+        /** @type {StorageEntry[]} */
         const newEntries = message.args;
         for (const [key, value] of newEntries) {
           value != null || Fail`attempt to append with no value`;
@@ -203,6 +207,18 @@ export const makeFakeStorageKit = (rootPath, rootOptions) => {
 harden(makeFakeStorageKit);
 /** @typedef {ReturnType< typeof makeFakeStorageKit>} FakeStorageKit */
 
+/**
+ * @typedef MockChainStorageRootMethods
+ * @property {(path: string, marshaller?: Marshaller, index?: number) => unknown} getBody
+ * Defaults to deserializing slot references into plain Remotable
+ * objects having the specified interface name (as from `Far(iface)`),
+ * but can accept a different marshaller for producing Remotables
+ * that e.g. embed the slot string in their iface name.
+ * @property {() => string[]} keys
+ */
+/** @typedef {StorageNode & MockChainStorageRootMethods} MockChainStorageRoot */
+
+/** @returns {MockChainStorageRoot} */
 export const makeMockChainStorageRoot = () => {
   const { rootNode, data } = makeFakeStorageKit('mockChainStorageRoot');
   return Far('mockChainStorage', {
@@ -214,7 +230,7 @@ export const makeMockChainStorageRoot = () => {
      * that e.g. embed the slot string in their iface name.
      *
      * @param {string} path
-     * @param {import('./lib-chainStorage.js').Marshaller} marshaller
+     * @param {Marshaller} marshaller
      * @param {number} [index]
      * @returns {unknown}
      */
@@ -228,4 +244,3 @@ export const makeMockChainStorageRoot = () => {
     keys: () => [...data.keys()],
   });
 };
-/** @typedef {ReturnType<typeof makeMockChainStorageRoot>} MockChainStorageRoot */
diff --git a/packages/internal/test/test-storage-test-utils.js b/packages/internal/test/test-storage-test-utils.js
index 5eab748c657..b4d6a76d19b 100644
--- a/packages/internal/test/test-storage-test-utils.js
+++ b/packages/internal/test/test-storage-test-utils.js
@@ -264,7 +264,7 @@ test('makeFakeStorageKit sequence data', async t => {
 });
 
 const testUnmarshaller = test.macro((t, format) => {
-  /** @type {(val: SlottedRemotable) => string} */
+  /** @type {(val: import('@endo/marshal').RemotableObject & SlottedRemotable) => string} */
   const convertValToSlot = val => val.getBoardId();
   const serializeBodyFormat = /** @type {any} */ (format);
   const m = makeMarshal(convertValToSlot, undefined, { serializeBodyFormat });
diff --git a/packages/kmarshal/src/kmarshal.js b/packages/kmarshal/src/kmarshal.js
index b72a204e4d0..707daf6d828 100644
--- a/packages/kmarshal/src/kmarshal.js
+++ b/packages/kmarshal/src/kmarshal.js
@@ -2,7 +2,10 @@ import { Far, passStyleOf } from '@endo/far';
 import { makeMarshal } from '@endo/marshal';
 import { assert, Fail } from '@agoric/assert';
 
-/** @import { ERef } from '@endo/far' */
+/**
+ * @import { ERef } from '@endo/far';
+ * @import {ConvertSlotToVal} from '@endo/marshal';
+ */
 
 // Simple wrapper for serializing and unserializing marshalled values inside the
 // kernel, where we don't actually want to use clists nor actually allocate real
@@ -98,9 +101,7 @@ export { makeStandinPromise };
 harden(makeStandinPromise);
 
 /**
- * @param {string} kref
- * @param {string} [iface]
- * @returns {ERef<KCap>}
+ * @type {ConvertSlotToVal<string>}
  */
 export const kslot = (kref, iface = 'undefined') => {
   assert.typeof(kref, 'string');
diff --git a/packages/network/package.json b/packages/network/package.json
index 5a773a6f521..56609704f13 100644
--- a/packages/network/package.json
+++ b/packages/network/package.json
@@ -68,6 +68,6 @@
     "workerThreads": false
   },
   "typeCoverage": {
-    "atLeast": 89.73
+    "atLeast": 89.5
   }
 }
diff --git a/packages/network/src/types.js b/packages/network/src/types.js
index 204a8a4fcaf..e056672bc5a 100644
--- a/packages/network/src/types.js
+++ b/packages/network/src/types.js
@@ -3,7 +3,10 @@
 // Ensure this is a module.
 export {};
 
-/** @import {PromiseVow, Remote} from '@agoric/vow' */
+/**
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ * @import {PromiseVow, Remote} from '@agoric/vow';
+ */
 
 /**
  * @template {import('@endo/exo').Methods} M
@@ -22,9 +25,12 @@ export {};
  */
 
 /**
- * @typedef {object} Closable A closable object
+ * @typedef {object} ClosableI A closable object
  * @property {() => PromiseVow<void>} close Terminate the object
  */
+/**
+ * @typedef {RemotableObject & ClosableI} Closable
+ */
 
 /**
  * @typedef {object} Protocol The network Protocol
@@ -73,7 +79,7 @@ export {};
  */
 
 /**
- * @typedef {object} Connection
+ * @typedef {object} ConnectionI
  * @property {(
  *   packetBytes: Bytes,
  *   opts?: Record<string, any>,
@@ -84,6 +90,9 @@ export {};
  *   connection
  * @property {() => Endpoint} getRemoteAddress Get the name of the counterparty
  */
+/**
+ * @typedef {RemotableObject & ConnectionI} Connection
+ */
 
 /**
  * @typedef {object} ConnectionHandler A handler for a given Connection
diff --git a/packages/notifier/package.json b/packages/notifier/package.json
index df54287d709..2113eccd82e 100644
--- a/packages/notifier/package.json
+++ b/packages/notifier/package.json
@@ -76,6 +76,6 @@
     "timeout": "2m"
   },
   "typeCoverage": {
-    "atLeast": 89.76
+    "atLeast": 90.34
   }
 }
diff --git a/packages/notifier/src/stored-notifier.js b/packages/notifier/src/stored-notifier.js
index ef36fd952c4..0f434ed4789 100644
--- a/packages/notifier/src/stored-notifier.js
+++ b/packages/notifier/src/stored-notifier.js
@@ -9,6 +9,7 @@ import { observeNotifier } from './asyncIterableAdaptor.js';
  * @import {ERef} from '@endo/far';
  * @import {BaseNotifier, Notifier} from './types.js';
  * @import {Marshaller, StoredFacet, StorageNode, Unserializer} from '@agoric/internal/src/lib-chainStorage.js';
+ * @import {PassableCap, RemotableObject} from '@endo/pass-style';
  */
 
 /**
@@ -25,7 +26,7 @@ import { observeNotifier } from './asyncIterableAdaptor.js';
  * the iteration themselves, or obtain information to subscribe to the stored
  * data out-of-band.
  *
- * @template T
+ * @template {PassableCap} T
  * @param {ERef<Notifier<T>>} notifier
  * @param {ERef<StorageNode>} storageNode
  * @param {ERef<Marshaller>} marshaller
diff --git a/packages/notifier/src/storesub.js b/packages/notifier/src/storesub.js
index bed0f4e9185..bd9d8ba64a5 100644
--- a/packages/notifier/src/storesub.js
+++ b/packages/notifier/src/storesub.js
@@ -44,7 +44,7 @@ export const forEachPublicationRecord = async (subscriber, consumeValue) => {
  * the iteration themselves, or obtain information to subscribe to the stored
  * data out-of-band.
  *
- * @template T
+ * @template {import('@endo/marshal').PassableCap} T
  * @param {Subscriber<T>} subscriber
  * @param {ERef<StorageNode>} storageNode
  * @param {ERef<ReturnType<typeof makeMarshal>>} marshaller
diff --git a/packages/notifier/src/types.js b/packages/notifier/src/types.js
index d8594fb07ee..7533439b677 100644
--- a/packages/notifier/src/types.js
+++ b/packages/notifier/src/types.js
@@ -226,7 +226,7 @@ export {};
 
 /**
  * @template T
- * @typedef {NotifierInternals<T> &
+ * @typedef {import('@endo/marshal').RemotableObject & NotifierInternals<T> &
  *   ForkableAsyncIterable<T, T> &
  *   SharableNotifier<T>
  * } Notifier an object that can be used to get the current state or updates
@@ -249,7 +249,7 @@ export {};
 /**
  * @template T
  * @typedef {object} NotifierRecord the produced notifier/updater pair
- * @property {IterationObserver<T>} updater the (closely-held) notifier producer
+ * @property {import('@endo/marshal').RemotableObject & IterationObserver<T>} updater the (closely-held) notifier producer
  * @property {Notifier<T>} notifier the (widely-held) notifier consumer
  */
 
diff --git a/packages/notifier/test/iterable-testing-tools.js b/packages/notifier/test/iterable-testing-tools.js
index 6849cd80704..1f74a720fa7 100644
--- a/packages/notifier/test/iterable-testing-tools.js
+++ b/packages/notifier/test/iterable-testing-tools.js
@@ -65,7 +65,7 @@ const refReason = Error('bar');
  *
  * @param {boolean} fails Does the returned async iterable finish successfully
  * or fail?
- * @returns {AsyncIterable<Passable>}
+ * @returns {AsyncIterable<any>}
  */
 const makeTestIterable = fails => {
   return harden({
@@ -251,7 +251,7 @@ export const paula = iterationObserver => {
  * See the Alice example  in the README
  *
  * @param {AsyncIterable<Passable>} asyncIterable
- * @returns {Promise<Passable[]>}
+ * @returns {Promise<any[]>}
  */
 export const alice = async asyncIterable => {
   const log = [];
diff --git a/packages/orchestration/package.json b/packages/orchestration/package.json
index ee44b444b45..5ee60428fce 100644
--- a/packages/orchestration/package.json
+++ b/packages/orchestration/package.json
@@ -80,6 +80,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 96.39
+    "atLeast": 96.18
   }
 }
diff --git a/packages/orchestration/src/exos/localchainAccountKit.js b/packages/orchestration/src/exos/localchainAccountKit.js
index 7a023a96844..37c71421b7e 100644
--- a/packages/orchestration/src/exos/localchainAccountKit.js
+++ b/packages/orchestration/src/exos/localchainAccountKit.js
@@ -61,6 +61,7 @@ export const prepareLocalchainAccountKit = (baggage, makeRecorderKit, zcf) => {
      */
     (account, storageNode) => {
       // must be the fully synchronous maker because the kit is held in durable state
+      // @ts-expect-error XXX Patterns
       const topicKit = makeRecorderKit(storageNode, PUBLIC_TOPICS.account[1]);
 
       return { account, topicKit };
diff --git a/packages/orchestration/src/exos/stakingAccountKit.js b/packages/orchestration/src/exos/stakingAccountKit.js
index ba0096e496a..c32f492fcc3 100644
--- a/packages/orchestration/src/exos/stakingAccountKit.js
+++ b/packages/orchestration/src/exos/stakingAccountKit.js
@@ -117,6 +117,7 @@ export const prepareStakingAccountKit = (baggage, makeRecorderKit, zcf) => {
      */
     (account, storageNode, chainAddress, icqConnection, bondDenom) => {
       // must be the fully synchronous maker because the kit is held in durable state
+      // @ts-expect-error XXX Patterns
       const topicKit = makeRecorderKit(storageNode, PUBLIC_TOPICS.account[1]);
 
       return { account, chainAddress, topicKit, icqConnection, bondDenom };
diff --git a/packages/pegasus/package.json b/packages/pegasus/package.json
index e09454b5b9f..12ab50c5d41 100644
--- a/packages/pegasus/package.json
+++ b/packages/pegasus/package.json
@@ -70,6 +70,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 91.45
+    "atLeast": 90.68
   }
 }
diff --git a/packages/pegasus/src/contract.js b/packages/pegasus/src/contract.js
index e378b30c104..16d4c33f4c0 100644
--- a/packages/pegasus/src/contract.js
+++ b/packages/pegasus/src/contract.js
@@ -1,3 +1,4 @@
+// @ts-check
 import { prepareVowTools } from '@agoric/vat-data/vow.js';
 import { makeDurableZone } from '@agoric/zone/durable.js';
 import { makePegasus } from './pegasus.js';
@@ -6,10 +7,14 @@ import '@agoric/zoe/exported.js';
 
 import '../exported.js';
 
+/**
+ * @import {Remote} from '@agoric/vow';
+ */
+
 /**
  * @type {ContractStartFn<import('./pegasus.js').Pegasus, never, {}, {
- *   board: ERef<BoardDepositFacet>,
- *   namesByAddress: ERef<import('@agoric/vats').NameHub>
+ *   board: Remote<BoardDepositFacet>,
+ *   namesByAddress: Remote<import('@agoric/vats').NameHub>
  * }>}
  */
 export const start = (zcf, privateArgs, baggage) => {
@@ -23,10 +28,12 @@ export const start = (zcf, privateArgs, baggage) => {
   // start requires that the object passed in must be durable. Given that we
   // haven't made pegasus durable yet, we'll wrap its non-durable methods within
   // an exo object to workaround this requirement.
+  // @ts-expect-error makePegasus returns a remotable object
   const publicFacet = zone.exo('PublicFacet', undefined, {
     ...makePegasus({ zcf, board, namesByAddress, when }),
   });
 
+  // @ts-expect-error XXX durable wrapping non-durable
   return harden({
     publicFacet,
   });
diff --git a/packages/smart-wallet/package.json b/packages/smart-wallet/package.json
index 4548fbcdb9b..93084dbce86 100644
--- a/packages/smart-wallet/package.json
+++ b/packages/smart-wallet/package.json
@@ -68,6 +68,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 93.99
+    "atLeast": 94.36
   }
 }
diff --git a/packages/smart-wallet/src/invitations.js b/packages/smart-wallet/src/invitations.js
index 34d34a6d872..729686f6718 100644
--- a/packages/smart-wallet/src/invitations.js
+++ b/packages/smart-wallet/src/invitations.js
@@ -61,7 +61,7 @@ const MAX_PIPE_LENGTH = 2;
  * @param {ERef<ZoeService>} zoe
  * @param {ERef<import('@agoric/vats').NameHub>} agoricNames
  * @param {Brand<'set'>} invitationBrand
- * @param {Purse<'set'>} invitationsPurse
+ * @param {Purse<'set', InvitationDetails>} invitationsPurse
  * @param {(fromOfferId: string) => import('./types.js').InvitationMakers} getInvitationContinuation
  */
 export const makeInvitationsHelper = (
@@ -103,9 +103,7 @@ export const makeInvitationsHelper = (
       mustMatch(spec, shape.PurseInvitationSpec);
 
       const { instance, description } = spec;
-      // @ts-expect-error TS thinks it's always true. I'm doubtful.
       (instance && description) || Fail`missing instance or description`;
-      /** @type {Amount<'set'>} */
       const purseAmount = await E(invitationsPurse).getCurrentAmount();
       const invitations = AmountMath.getValue(invitationBrand, purseAmount);
 
diff --git a/packages/smart-wallet/src/marshal-contexts.js b/packages/smart-wallet/src/marshal-contexts.js
index 475dd4515e5..99789be72e4 100644
--- a/packages/smart-wallet/src/marshal-contexts.js
+++ b/packages/smart-wallet/src/marshal-contexts.js
@@ -6,7 +6,11 @@ import { DEFAULT_PREFIX } from '@agoric/vats/src/lib-board.js';
 
 const { Fail, quote: q } = assert;
 
-/** @import {BoardId} from '@agoric/vats/src/lib-board.js' */
+/**
+ * @import {PassableCap} from '@endo/marshal';
+ * @import {Key} from '@endo/patterns';
+ * @import {BoardId} from '@agoric/vats/src/lib-board.js';
+ */
 
 /**
  * ID from a board made with { prefix: DEFAULT_PREFIX }
@@ -23,7 +27,7 @@ const isDefaultBoardId = specimen => {
  * using prefixes.
  *
  * @template {Record<string, IdTable<*,*>>} T
- * @typedef {`${string & keyof T}:${Digits}`} WalletSlot<T>
+ * @typedef {`${string & keyof T}:${Digits}`} WalletSlot
  */
 /**
  * @template {string} K
@@ -70,7 +74,7 @@ const parseWalletSlot = (tables, slot) => {
  * we an mix them without confusion.
  *
  * @template {Record<string, IdTable<*,*>>} T
- * @typedef {WalletSlot<T> | BoardId} MixedSlot<T>
+ * @typedef {WalletSlot<T> | BoardId} MixedSlot
  */
 /**
  * @typedef {`1` | `12` | `123`} Digits - 1 or more digits.
@@ -79,8 +83,8 @@ const parseWalletSlot = (tables, slot) => {
  */
 
 /**
- * @template Slot
- * @template Val
+ * @template {Key} Slot
+ * @template {PassableCap} Val
  *
  * @typedef {{
  *   bySlot: MapStore<Slot, Val>,
@@ -89,9 +93,9 @@ const parseWalletSlot = (tables, slot) => {
  */
 
 /**
- * @template Slot
- * @template Val
- * @param {IdTable<Slot, Val>} table
+ * @template {Key} Slot
+ * @template {PassableCap} Val
+ * @param {IdTable<Slot, PassableCap>} table
  * @param {Slot} slot
  * @param {Val} val
  */
@@ -126,13 +130,13 @@ export const makeExportContext = () => {
       byVal: makeScalarMapStore(),
     },
     // TODO: offer, contact, dapp
-    /** @type {IdTable<number, unknown>} */
+    /** @type {IdTable<number, PassableCap>} */
     unknown: {
       bySlot: makeScalarMapStore(),
       byVal: makeScalarMapStore(),
     },
   };
-  /** @type {IdTable<BoardId, unknown>} */
+  /** @type {IdTable<BoardId, PassableCap>} */
   const boardObjects = {
     bySlot: makeScalarMapStore(),
     byVal: makeScalarMapStore(),
@@ -161,7 +165,7 @@ export const makeExportContext = () => {
   let unknownNonce = 0;
 
   /**
-   * @param {unknown} val
+   * @param {PassableCap} val
    * @returns {MixedSlot<typeof walletObjects>}
    */
   const valToSlot = val => {
@@ -181,7 +185,7 @@ export const makeExportContext = () => {
   };
 
   /**
-   * @template V
+   * @template {PassableCap} V
    * @param {string & keyof typeof walletObjects} kind
    * @param {IdTable<number, V>} table
    */
@@ -208,14 +212,14 @@ export const makeExportContext = () => {
     purseEntries: walletObjects.purse.bySlot.entries,
     /**
      * @param {BoardId} id
-     * @param {unknown} val
+     * @param {PassableCap} val
      */
     initBoardId: (id, val) => {
       initSlotVal(boardObjects, id, val);
     },
     /**
      * @param {BoardId} id
-     * @param {unknown} val
+     * @param {PassableCap} val
      */
     ensureBoardId: (id, val) => {
       if (boardObjects.byVal.has(val)) {
@@ -238,35 +242,35 @@ const defaultMakePresence = iface => {
  * Make context for marshalling wallet or board data.
  * To be imported into the client, which never exports objects.
  *
- * @param {(iface: string) => unknown} [makePresence]
+ * @param {(iface: string) => PassableCap} [makePresence]
  */
 export const makeImportContext = (makePresence = defaultMakePresence) => {
   const walletObjects = {
-    /** @type {IdTable<number, unknown>} */
+    /** @type {IdTable<number, PassableCap>} */
     purse: {
       bySlot: makeScalarMapStore(),
       byVal: makeScalarMapStore(),
     },
-    /** @type {IdTable<number, unknown>} */
+    /** @type {IdTable<number, PassableCap>} */
     payment: {
       bySlot: makeScalarMapStore(),
       byVal: makeScalarMapStore(),
     },
-    /** @type {IdTable<number, unknown>} */
+    /** @type {IdTable<number, PassableCap>} */
     unknown: {
       bySlot: makeScalarMapStore(),
       byVal: makeScalarMapStore(),
     },
   };
-  /** @type {IdTable<BoardId, unknown>} */
+  /** @type {IdTable<BoardId, PassableCap>} */
   const boardObjects = {
     bySlot: makeScalarMapStore(),
     byVal: makeScalarMapStore(),
   };
 
   /**
-   * @template Slot
-   * @template Val
+   * @template {Key} Slot
+   * @template {PassableCap} Val
    * @param {IdTable<Slot, Val>} table
    * @param {Slot} slot
    * @param {string} iface
@@ -308,7 +312,7 @@ export const makeImportContext = (makePresence = defaultMakePresence) => {
 
   const valToSlot = {
     fromBoard: val => boardObjects.byVal.get(val),
-    /** @param {unknown} val */
+    /** @param {PassableCap} val */
     fromMyWallet: val => {
       const kind = findKey(walletObjects, k => walletObjects[k].byVal.has(val));
       if (kind === undefined) {
@@ -334,14 +338,14 @@ export const makeImportContext = (makePresence = defaultMakePresence) => {
   return harden({
     /**
      * @param {BoardId} id
-     * @param {unknown} val
+     * @param {PassableCap} val
      */
     initBoardId: (id, val) => {
       initSlotVal(boardObjects, id, val);
     },
     /**
      * @param {BoardId} id
-     * @param {unknown} val
+     * @param {PassableCap} val
      */
     ensureBoardId: (id, val) => {
       if (boardObjects.byVal.has(val)) {
diff --git a/packages/smart-wallet/src/offers.js b/packages/smart-wallet/src/offers.js
index bd4b73c0f01..a68536b7dab 100644
--- a/packages/smart-wallet/src/offers.js
+++ b/packages/smart-wallet/src/offers.js
@@ -10,7 +10,7 @@ import '@agoric/zoe/src/zoeService/types-ambient.js';
  *   id: OfferId,
  *   invitationSpec: import('./invitations.js').InvitationSpec,
  *   proposal: Proposal,
- *   offerArgs?: unknown
+ *   offerArgs?: import('@endo/marshal').Passable,
  * }} OfferSpec
  */
 
diff --git a/packages/smart-wallet/src/smartWallet.js b/packages/smart-wallet/src/smartWallet.js
index 9ef0da19135..db92dfdbe4d 100644
--- a/packages/smart-wallet/src/smartWallet.js
+++ b/packages/smart-wallet/src/smartWallet.js
@@ -55,16 +55,7 @@ const trace = makeTracer('SmrtWlt');
  * @see {@link ../README.md}}
  */
 
-/** @typedef {number | string} OfferId */
-
-/**
- * @typedef {{
- *   id: OfferId,
- *   invitationSpec: import('./invitations').InvitationSpec,
- *   proposal: Proposal,
- *   offerArgs?: unknown
- * }} OfferSpec
- */
+/** @import {OfferSpec, OfferId} from './offers.js'; */
 
 /**
  * @typedef {{
@@ -150,7 +141,7 @@ const trace = makeTracer('SmrtWlt');
  *   address: string,
  *   bank: ERef<import('@agoric/vats/src/vat-bank.js').Bank>,
  *   currentStorageNode: StorageNode,
- *   invitationPurse: Purse<'set'>,
+ *   invitationPurse: Purse<'set', InvitationDetails>,
  *   walletStorageNode: StorageNode,
  * }} UniqueParams
  *
@@ -770,7 +761,6 @@ export const prepareSmartWallet = (baggage, shared) => {
           const { registry, invitationBrand } = shared;
 
           if (registry.has(brand)) {
-            // @ts-expect-error virtual purse
             return E(state.bank).getPurse(brand);
           } else if (invitationBrand === brand) {
             return state.invitationPurse;
diff --git a/packages/smart-wallet/test/contexts.js b/packages/smart-wallet/test/contexts.js
index 7429634122a..728c64a090a 100644
--- a/packages/smart-wallet/test/contexts.js
+++ b/packages/smart-wallet/test/contexts.js
@@ -62,7 +62,6 @@ export const makeDefaultTestContext = async (t, makeSpace) => {
   };
 
   const anchor = withAmountUtils(
-    // @ts-expect-error incomplete typedef
     await deeplyFulfilledObject(consume.testFirstAnchorKit),
   );
 
diff --git a/packages/smart-wallet/test/swingsetTests/upgradeWalletFactory/walletFactory-V2.js b/packages/smart-wallet/test/swingsetTests/upgradeWalletFactory/walletFactory-V2.js
index b3282f9f38b..a28040be2ed 100644
--- a/packages/smart-wallet/test/swingsetTests/upgradeWalletFactory/walletFactory-V2.js
+++ b/packages/smart-wallet/test/swingsetTests/upgradeWalletFactory/walletFactory-V2.js
@@ -27,6 +27,7 @@ export const prepare = async (zcf, privateArgs, baggage) => {
   const zoe = zcf.getZoeService();
   const { storageNode, walletBridgeManager } = privateArgs;
 
+  /** @type {MapStore<string, import('../../../src/smartWallet.js').SmartWallet>} */
   const walletsByAddress = provideDurableMapStore(baggage, 'walletsByAddress');
   const provider = makeAtomicProvider(walletsByAddress);
 
diff --git a/packages/smart-wallet/test/test-addAsset.js b/packages/smart-wallet/test/test-addAsset.js
index a9072c883b2..0ba36801ba4 100644
--- a/packages/smart-wallet/test/test-addAsset.js
+++ b/packages/smart-wallet/test/test-addAsset.js
@@ -185,8 +185,9 @@ const makeScenario = t => {
     const uiBridge = Far('UIBridge', {
       /** @param {import('@endo/marshal').CapData<string>} offerEncoding */
       proposeOffer: async offerEncoding => {
-        /** @type {import('../src/offers.js').OfferSpec} */
-        const offer = ctx.fromBoard.fromCapData(offerEncoding);
+        const offer = /** @type {import('../src/offers.js').OfferSpec} */ (
+          ctx.fromBoard.fromCapData(offerEncoding)
+        );
         const { give, want } = offer.proposal;
         for await (const [kw, amt] of entries({ ...give, ...want })) {
           // @ts-expect-error
@@ -435,7 +436,6 @@ test.serial('trading in non-vbank asset: game real-estate NFTs', async t => {
     const {
       status: { id, result, payouts },
     } = update;
-    // @ts-expect-error cast value to copyBag
     const names = payouts?.Places.value.payload.map(([name, _qty]) => name);
     t.log(id, 'result:', result, ', payouts:', names.join(', '));
 
diff --git a/packages/smart-wallet/test/test-invitation1.js b/packages/smart-wallet/test/test-invitation1.js
index 93808a1154a..ad5697b13ff 100644
--- a/packages/smart-wallet/test/test-invitation1.js
+++ b/packages/smart-wallet/test/test-invitation1.js
@@ -150,7 +150,7 @@ test.before(async t => (t.context = await makeTestContext(t)));
 test.serial('handle failure to create invitation', async t => {
   const { powers, makeSmartWallet, spendable, shared } = t.context;
   const { chainStorage, board } = powers.consume;
-  /** @type {Issuer<'set'>} */
+  /** @type {Issuer<'set', InvitationDetails>} */
   // @ts-expect-error cast
   const invitationIssuer = powers.issuer.consume.Invitation;
   const address = 'agoric1234';
diff --git a/packages/smart-wallet/test/test-marshal-contexts.js b/packages/smart-wallet/test/test-marshal-contexts.js
index 596096da37f..7ee179d0eac 100644
--- a/packages/smart-wallet/test/test-marshal-contexts.js
+++ b/packages/smart-wallet/test/test-marshal-contexts.js
@@ -62,10 +62,13 @@ test('makeImportContext preserves identity across AMM and wallet', t => {
     slots: ['board011'],
   });
 
-  /** @type {Brand[]} */
-  const [b1] = context.fromBoard.fromCapData(ammMetricsCapData);
-  /** @type {Brand[]} */
-  const [b2] = context.fromBoard.fromCapData(amm.getMetrics());
+  const [b1] = /** @type {Brand[]} */ (
+    context.fromBoard.fromCapData(ammMetricsCapData)
+  );
+
+  const [b2] = /** @type {Brand[]} */ (
+    context.fromBoard.fromCapData(amm.getMetrics())
+  );
   t.is(b1, b2, 'unserialization twice from same source');
 
   const myWallet = makeOnChainWallet(board);
@@ -85,6 +88,7 @@ test('makeImportContext preserves identity across AMM and wallet', t => {
     slots: ['board011', 'purse:ATOM'],
   });
 
+  /** @type {any} */
   const walletState = context.fromMyWallet.fromCapData(walletCapData);
   t.is(walletState[0].brand, b1, 'unserialization across sources');
 
diff --git a/packages/solo/src/pipe-entrypoint.js b/packages/solo/src/pipe-entrypoint.js
index 0914ccfa36e..81781f78f9d 100644
--- a/packages/solo/src/pipe-entrypoint.js
+++ b/packages/solo/src/pipe-entrypoint.js
@@ -29,6 +29,7 @@ const main = async () => {
       mutex.resolve(undefined);
       return;
     }
+    /** @type {any} */
     const as = parse(`${msg}`);
     deliverator(...as).then(() => send('go'));
   });
diff --git a/packages/solo/src/pipe.js b/packages/solo/src/pipe.js
index 4a743e4144e..ade11381e69 100644
--- a/packages/solo/src/pipe.js
+++ b/packages/solo/src/pipe.js
@@ -31,6 +31,7 @@ export const connectToPipe = async ({ method, args, deliverInboundToMbx }) => {
       return;
     }
     // console.log('pipe.js', msg);
+    /** @type {any} */
     const as = parse(`${msg}`);
     deliverInboundToMbx(...as).then(() => cp.send('go'));
   });
diff --git a/packages/store/package.json b/packages/store/package.json
index 56f10b4e2dd..baf5439dd02 100644
--- a/packages/store/package.json
+++ b/packages/store/package.json
@@ -58,6 +58,6 @@
     "timeout": "2m"
   },
   "typeCoverage": {
-    "atLeast": 86.34
+    "atLeast": 89.45
   }
 }
diff --git a/packages/store/src/stores/scalarMapStore.js b/packages/store/src/stores/scalarMapStore.js
index 63ee0354485..b2c83293183 100644
--- a/packages/store/src/stores/scalarMapStore.js
+++ b/packages/store/src/stores/scalarMapStore.js
@@ -16,9 +16,9 @@ import { makeWeakMapStoreMethods } from './scalarWeakMapStore.js';
 import { makeCurrentKeysKit } from './store-utils.js';
 
 /**
- * @import {Passable} from '@endo/pass-style');
- * @import {Key, Pattern} from '@endo/patterns');
- * @import {MapStore, StoreOptions} from '../types.js';
+ * @import {Passable} from '@endo/pass-style';
+ * @import {Key, Pattern} from '@endo/patterns';
+ * @import {MapStore, MapStoreMethods, StoreOptions} from '../types.js';
  */
 
 const { quote: q } = assert;
@@ -31,7 +31,7 @@ const { quote: q } = assert;
  * @param {(k: K, v: V) => void} assertKVOkToSet
  * @param {(k: K) => void} [assertKeyOkToDelete]
  * @param {string} [tag]
- * @returns {MapStore<K, V>}
+ * @returns {MapStoreMethods<K, V>}
  */
 export const makeMapStoreMethods = (
   jsmap,
@@ -133,11 +133,9 @@ export const makeMapStoreMethods = (
  * or remotables. Other storeMaps will accept, for example, copyArrays and
  * copyRecords, as keys and look them up based on equality of their contents.
  *
- * @template {Key} K
- * @template {Passable} V
  * @param {string} [tag] - the column name for the key
  * @param {StoreOptions} [options]
- * @returns {MapStore<K, V>}
+ * @returns {MapStore<any, any>}
  */
 export const makeScalarMapStore = (
   tag = 'key',
diff --git a/packages/store/src/stores/scalarSetStore.js b/packages/store/src/stores/scalarSetStore.js
index e7698954cd9..620e6ac37ab 100644
--- a/packages/store/src/stores/scalarSetStore.js
+++ b/packages/store/src/stores/scalarSetStore.js
@@ -11,19 +11,19 @@ import { makeWeakSetStoreMethods } from './scalarWeakSetStore.js';
 import { makeCurrentKeysKit } from './store-utils.js';
 
 /**
- * @import {Key, Pattern} from '@endo/patterns');
- * @import {SetStore, StoreOptions} from '../types.js';
+ * @import {Key, Pattern} from '@endo/patterns';
+ * @import {SetStore, SetStoreMethods, StoreOptions} from '../types.js';
  */
 
 const { quote: q } = assert;
 
 /**
- * @template K
+ * @template {Key} K
  * @param {Set<K>} jsset
  * @param {(k: K) => void} assertKeyOkToAdd
  * @param {(k: K) => void} [assertKeyOkToDelete]
  * @param {string} [keyName]
- * @returns {SetStore<K>}
+ * @returns {SetStoreMethods<K>}
  */
 export const makeSetStoreMethods = (
   jsset,
diff --git a/packages/store/src/stores/scalarWeakMapStore.js b/packages/store/src/stores/scalarWeakMapStore.js
index ebfee6b9aa6..6bf46df0cbc 100644
--- a/packages/store/src/stores/scalarWeakMapStore.js
+++ b/packages/store/src/stores/scalarWeakMapStore.js
@@ -6,12 +6,17 @@ import {
   isCopyMap,
 } from '@endo/patterns';
 
-/** @import {WeakMapStore, StoreOptions} from '../types.js'; */
+/**
+ * @import {Key} from '@endo/patterns';
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ * @import {WeakMapStore, StoreOptions} from '../types.js';
+ */
 
 const { quote: q, Fail } = assert;
 
 /**
- * @template K,V
+ * @template {Key} K
+ * @template {Passable} V
  * @param {WeakMap<K & object, V>} jsmap
  * @param {(k: K, v: V) => void} assertKVOkToAdd
  * @param {(k: K, v: V) => void} assertKVOkToSet
@@ -66,6 +71,7 @@ export const makeWeakMapStoreMethods = (
     addAll: entries => {
       if (typeof entries[Symbol.iterator] !== 'function') {
         if (Object.isFrozen(entries) && isCopyMap(entries)) {
+          // @ts-expect-error XXX
           entries = getCopyMapEntries(entries);
         } else {
           Fail`provided data source is not iterable: ${entries}`;
@@ -96,7 +102,7 @@ export const makeWeakMapStoreMethods = (
  * @template K,V
  * @param {string} [tag] - tag for debugging
  * @param {StoreOptions} [options]
- * @returns {WeakMapStore<K, V>}
+ * @returns {RemotableObject & WeakMapStore<K, V>}
  */
 export const makeScalarWeakMapStore = (
   tag = 'key',
diff --git a/packages/store/src/stores/scalarWeakSetStore.js b/packages/store/src/stores/scalarWeakSetStore.js
index 8bc8cab8a9c..cc5762b4785 100644
--- a/packages/store/src/stores/scalarWeakSetStore.js
+++ b/packages/store/src/stores/scalarWeakSetStore.js
@@ -8,15 +8,18 @@ import {
 
 const { quote: q, Fail } = assert;
 
-/** @import {StoreOptions, WeakSetStore} from '@agoric/store'; */
+/**
+ * @import {Key} from '@endo/patterns';
+ * @import {StoreOptions, WeakSetStore, WeakSetStoreMethods} from '@agoric/store';
+ */
 
 /**
- * @template K
+ * @template {Key} K
  * @param {WeakSet<K & object>} jsset
  * @param {(k: K) => void} assertKeyOkToAdd
  * @param {(k: K) => void} [assertKeyOkToDelete]
  * @param {string} [keyName]
- * @returns {WeakSetStore<K>}
+ * @returns {WeakSetStoreMethods<K>}
  */
 export const makeWeakSetStoreMethods = (
   jsset,
@@ -50,6 +53,7 @@ export const makeWeakSetStoreMethods = (
     addAll: keys => {
       if (typeof keys[Symbol.iterator] !== 'function') {
         if (Object.isFrozen(keys) && isCopySet(keys)) {
+          // @ts-expect-error XXX
           keys = getCopySetKeys(keys);
         } else {
           Fail`provided data source is not iterable: ${keys}`;
diff --git a/packages/store/src/stores/store-utils.js b/packages/store/src/stores/store-utils.js
index 953386589fd..77ca084ee42 100644
--- a/packages/store/src/stores/store-utils.js
+++ b/packages/store/src/stores/store-utils.js
@@ -1,14 +1,42 @@
 import { Far } from '@endo/marshal';
+import { M, matches } from '@endo/patterns';
 
 /**
  * @import {RankCompare} from '@endo/marshal';
  * @import {MapStore, WeakMapStore} from '../types.js';
+ * @import {Passable} from '@endo/pass-style';
+ * @import {Key} from '@endo/patterns';
  */
 
 const { Fail, quote: q } = assert;
 
+// TODO: Undate `@endo/patterns` to export the original, and delete the
+// reimplementation here.
 /**
- * @template K,V
+ * Should behave identically to the one in `@endo/patterns`, but reimplemented
+ * for now because `@endo/patterns` forgot to export this one. This one is
+ * simple enough that I prefer a reimplementation to a deep import.
+ *
+ * @param {unknown} s
+ * @returns {s is CopySet}
+ */
+export const isCopySet = s => matches(s, M.set());
+
+// TODO: Undate `@endo/patterns` to export the original, and delete the
+// reimplementation here.
+/**
+ * Should behave identically to the one in `@endo/patterns`, but reimplemented
+ * for now because `@endo/patterns` forgot to export this one. This one is
+ * simple enough that I prefer a reimplementation to a deep import.
+ *
+ * @param {unknown} m
+ * @returns {m is CopyMap}
+ */
+export const isCopyMap = m => matches(m, M.map());
+
+/**
+ * @template {Key} K
+ * @template {Passable} V
  * @typedef {object} CurrentKeysKit
  * @property {(k: K, v?: V) => void} assertUpdateOnAdd
  * @property {(k: K) => void} assertUpdateOnDelete
@@ -16,7 +44,8 @@ const { Fail, quote: q } = assert;
  */
 
 /**
- * @template K,V
+ * @template {Key} K
+ * @template {Passable} V
  * @param {() => Iterable<K>} getRawKeys
  * @param {(k: K) => boolean} checkHas
  * @param {RankCompare} compare
@@ -91,7 +120,8 @@ harden(makeCurrentKeysKit);
  * already is one, return that. Otherwise, call `makeValue(key)`, remember it as
  * the value for that key, and return it.
  *
- * @template K,V
+ * @template {Key} K
+ * @template {Passable} V
  * @param {WeakMapStore<K, V>} mapStore
  * @param {K} key
  * @param {(key: K) => V} makeValue
@@ -116,8 +146,8 @@ harden(provideLazy);
  * termination to happen after the make completes and before it reaches durable
  * storage.
  *
- * @template K
- * @template V
+ * @template {Key} K
+ * @template {Passable} V
  * @param {WeakMapStore<K, V>} store
  */
 export const makeAtomicProvider = store => {
@@ -167,13 +197,14 @@ export const makeAtomicProvider = store => {
 };
 harden(makeAtomicProvider);
 /**
- * @template K
- * @template V
+ * @template {Key} K
+ * @template {Passable} V
  * @typedef {ReturnType<typeof makeAtomicProvider<K, V>>} AtomicProvider<K, V>
  */
 
 /**
- * @template K, V
+ * @template {Key} K
+ * @template {Passable} V
  * @param {MapStore<K, V[]>} mapStore
  * @param {K} key
  * @param {V} item
diff --git a/packages/store/src/types.js b/packages/store/src/types.js
index f55b6f40047..45978b51cf4 100644
--- a/packages/store/src/types.js
+++ b/packages/store/src/types.js
@@ -6,7 +6,7 @@ export {};
 /**
  * Note TODO https://github.com/endojs/endo/issues/1488
  *
- * @import {Passable} from '@endo/pass-style'
+ * @import {Passable, RemotableObject} from '@endo/pass-style'
  * @import {CopySet, CopyMap, Pattern} from '@endo/patterns'
  * @import {Key} from '@endo/patterns'
  */
@@ -49,9 +49,10 @@ export {};
  * WeakStores, but with the additional query and query-update methods.
  */
 
+// TODO use Key for K
 /**
- * @template {Key & object} [K=Key]
- * @typedef {object} WeakSetStore
+ * @template K
+ * @typedef {object} WeakSetStoreMethods
  * @property {(key: K) => boolean} has Check if a key exists. The key can be any
  *   JavaScript value, though the answer will always be false for keys that
  *   cannot be found in this store.
@@ -60,12 +61,17 @@ export {};
  *   this store. For example a scalar store only allows primitives and
  *   remotables.
  * @property {(key: K) => void} delete Remove the key. Throws if not found.
- * @property {(keys: CopySet<K> | Iterable<K>) => void} addAll
+ * @property {(keys: CopySet<any> | Iterable<K>) => void} addAll
+ */
+/**
+ * @template K
+ * @typedef {RemotableObject & WeakSetStoreMethods<K>} WeakSetStore
  */
 
+// TODO use Key for K
 /**
- * @template {Key} [K=Key]
- * @typedef {object} SetStore
+ * @template K
+ * @typedef {object} SetStoreMethods
  * @property {(key: K) => boolean} has Check if a key exists. The key can be any
  *   JavaScript value, though the answer will always be false for keys that
  *   cannot be found in this store.
@@ -74,17 +80,23 @@ export {};
  *   this store. For example a scalar store only allows primitives and
  *   remotables.
  * @property {(key: K) => void} delete Remove the key. Throws if not found.
- * @property {(keys: CopySet<K> | Iterable<K>) => void} addAll
+ * @property {(keys: CopySet<any> | Iterable<K>) => void} addAll
  * @property {(keyPatt?: Pattern) => Iterable<K>} keys
  * @property {(keyPatt?: Pattern) => Iterable<K>} values
- * @property {(keyPatt?: Pattern) => CopySet<K>} snapshot
+ * @property {(keyPatt?: Pattern) => CopySet<any>} snapshot
  * @property {(keyPatt?: Pattern) => number} getSize
  * @property {(keyPatt?: Pattern) => void} clear
  */
+/**
+ * @template K
+ * @typedef {RemotableObject & SetStoreMethods<K>} SetStore
+ */
 
+// TODO use Key for K
+// TODO use Passable for V
 /**
- * @template {Key & object} [K=Key]
- * @template {Passable} [V=Passable]
+ * @template K
+ * @template V
  * @typedef {object} WeakMapStore
  * @property {(key: K) => boolean} has Check if a key exists. The key can be any
  *   JavaScript value, though the answer will always be false for keys that
@@ -96,13 +108,15 @@ export {};
  *   example a scalar store only allows primitives and remotables.
  * @property {(key: K, value: V) => void} set Set the key. Throws if not found.
  * @property {(key: K) => void} delete Remove the key. Throws if not found.
- * @property {(entries: CopyMap<K, V> | Iterable<[K, V]>) => void} addAll
+ * @property {(entries: CopyMap<any, any> | Iterable<[K, V]>) => void} addAll
  */
 
+// TODO use Key for K
+// TODO use Passable for V
 /**
- * @template {Key} [K=Key]
- * @template {Passable} [V=Passable]
- * @typedef {object} MapStore
+ * @template K
+ * @template V
+ * @typedef {object} MapStoreMethods
  * @property {(key: K) => boolean} has Check if a key exists. The key can be any
  *   JavaScript value, though the answer will always be false for keys that
  *   cannot be found in this map
@@ -113,14 +127,22 @@ export {};
  *   example a scalar store only allows primitives and remotables.
  * @property {(key: K, value: V) => void} set Set the key. Throws if not found.
  * @property {(key: K) => void} delete Remove the key. Throws if not found.
- * @property {(entries: CopyMap<K, V> | Iterable<[K, V]>) => void} addAll
+ * @property {(entries: CopyMap<any, Passable> | Iterable<[K, V]>) => void} addAll
  * @property {(keyPatt?: Pattern, valuePatt?: Pattern) => Iterable<K>} keys
  * @property {(keyPatt?: Pattern, valuePatt?: Pattern) => Iterable<V>} values
  * @property {(keyPatt?: Pattern, valuePatt?: Pattern) => Iterable<[K, V]>} entries
- * @property {(keyPatt?: Pattern, valuePatt?: Pattern) => CopyMap<K, V>} snapshot
+ * @property {(
+ *   keyPatt?: Pattern,
+ *   valuePatt?: Pattern,
+ * ) => CopyMap<any, Passable>} snapshot
  * @property {(keyPatt?: Pattern, valuePatt?: Pattern) => number} getSize
  * @property {(keyPatt?: Pattern, valuePatt?: Pattern) => void} clear
  */
+/**
+ * @template [K=any]
+ * @template [V=any]
+ * @typedef {RemotableObject & MapStoreMethods<K, V>} MapStore
+ */
 
 // ///////////////////////// Deprecated Legacy /////////////////////////////////
 
diff --git a/packages/swing-store/src/exporter.js b/packages/swing-store/src/exporter.js
index 799877e7e66..0666c7240ec 100644
--- a/packages/swing-store/src/exporter.js
+++ b/packages/swing-store/src/exporter.js
@@ -13,11 +13,11 @@ import { validateArtifactMode } from './internal.js';
 
 /**
  * @template T
- *  @typedef  { Iterable<T> | AsyncIterable<T> } AnyIterable<T>
+ * @typedef  { Iterable<T> | AsyncIterable<T> } AnyIterable
  */
 /**
  * @template T
- *  @typedef  { IterableIterator<T> | AsyncIterableIterator<T> } AnyIterableIterator<T>
+ * @typedef  { IterableIterator<T> | AsyncIterableIterator<T> } AnyIterableIterator
  */
 
 /**
diff --git a/packages/swing-store/src/snapStore.js b/packages/swing-store/src/snapStore.js
index 3d1ac29f743..3d67ad503b8 100644
--- a/packages/swing-store/src/snapStore.js
+++ b/packages/swing-store/src/snapStore.js
@@ -25,8 +25,7 @@ import { buffer } from './util.js';
  */
 
 /**
- * @template T
- *  @typedef { import('./exporter.js').AnyIterableIterator<T> } AnyIterableIterator<T>
+ * @import {AnyIterableIterator} from './exporter.js'
  */
 
 /**
diff --git a/packages/swingset-liveslots/package.json b/packages/swingset-liveslots/package.json
index 655192ee75e..9d5141ecb79 100644
--- a/packages/swingset-liveslots/package.json
+++ b/packages/swingset-liveslots/package.json
@@ -67,6 +67,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 75.29
+    "atLeast": 75.24
   }
 }
diff --git a/packages/swingset-liveslots/src/collectionManager.js b/packages/swingset-liveslots/src/collectionManager.js
index 3fa8a245be8..178514988f8 100644
--- a/packages/swingset-liveslots/src/collectionManager.js
+++ b/packages/swingset-liveslots/src/collectionManager.js
@@ -26,6 +26,10 @@ import {
 } from './vatstore-iterators.js';
 import { makeCache } from './cache.js';
 
+/**
+ * @import {ToCapData, FromCapData} from '@endo/marshal';
+ */
+
 // XXX TODO: The following key length limit was put in place due to limitations
 // in LMDB.  With the move away from LMDB, it is no longer relevant, but I'm
 // leaving it in place for the time being as a general defensive measure against
@@ -112,8 +116,8 @@ function makeSchemaCache(syscall, unserialize) {
  * @param {(val: any) => string | undefined} convertValToSlot
  * @param {*} convertSlotToVal
  * @param {*} registerValue
- * @param {import('@endo/marshal').ToCapData<string>} serialize
- * @param {import('@endo/marshal').FromCapData<string>} unserialize
+ * @param {ToCapData<string>} serialize
+ * @param {FromCapData<string>} unserialize
  * @param {(capDatas: any) => void} assertAcceptableSyscallCapdataSize
  */
 export function makeCollectionManager(
diff --git a/packages/swingset-liveslots/src/vatDataTypes.d.ts b/packages/swingset-liveslots/src/vatDataTypes.d.ts
index 39c3ff7a32d..b1af421557d 100644
--- a/packages/swingset-liveslots/src/vatDataTypes.d.ts
+++ b/packages/swingset-liveslots/src/vatDataTypes.d.ts
@@ -5,7 +5,6 @@
  * Behavior is a description when defining a kind of what facets it will have.
  * For the non-multi defineKind, there is just one facet so it doesn't have a key.
  */
-import type { InterfaceGuard, Pattern } from '@endo/patterns';
 import type {
   MapStore,
   SetStore,
@@ -14,6 +13,8 @@ import type {
   WeakSetStore,
 } from '@agoric/store';
 import type { StateShape } from '@endo/exo';
+import type { RemotableObject } from '@endo/pass-style';
+import type { InterfaceGuard, Pattern } from '@endo/patterns';
 import type { makeWatchedPromiseManager } from './watchedPromises.js';
 
 // TODO should be moved into @endo/patterns and eventually imported here
@@ -37,7 +38,7 @@ type OmitFirstArg<F> = F extends (x: any, ...args: infer P) => infer R
   ? (...args: P) => R
   : never;
 
-export type KindFacet<O> = {
+export type KindFacet<O> = RemotableObject & {
   [K in keyof O]: OmitFirstArg<O[K]>; // omit the 'context' parameter
 };
 
diff --git a/packages/swingset-liveslots/src/virtualObjectManager.js b/packages/swingset-liveslots/src/virtualObjectManager.js
index 63b653c8354..3a349f483cc 100644
--- a/packages/swingset-liveslots/src/virtualObjectManager.js
+++ b/packages/swingset-liveslots/src/virtualObjectManager.js
@@ -24,6 +24,7 @@ import {
  * @import {DurableKindHandle} from '@agoric/swingset-liveslots'
  * @import {DefineKindOptions} from '@agoric/swingset-liveslots'
  * @import {ClassContextProvider, KitContextProvider} from '@endo/exo'
+ * @import {ToCapData, FromCapData} from '@endo/marshal';
  */
 
 const {
@@ -276,8 +277,8 @@ const insistSameCapData = (oldCD, newCD) => {
  * @param {(slot: string) => object} requiredValForSlot
  * @param {*} registerValue  Function to register a new slot+value in liveSlot's
  *   various tables
- * @param {import('@endo/marshal').ToCapData<string>} serialize  Serializer for this vat
- * @param {import('@endo/marshal').FromCapData<string>} unserialize  Unserializer for this vat
+ * @param {ToCapData<string>} serialize  Serializer for this vat
+ * @param {FromCapData<string>} unserialize  Unserializer for this vat
  * @param {*} assertAcceptableSyscallCapdataSize  Function to check for oversized
  *   syscall params
  * @param {import('./types.js').LiveSlotsOptions} [liveSlotsOptions]
diff --git a/packages/swingset-runner/package.json b/packages/swingset-runner/package.json
index e6d0ae3eb12..c61d73a409e 100644
--- a/packages/swingset-runner/package.json
+++ b/packages/swingset-runner/package.json
@@ -59,6 +59,6 @@
     "timeout": "2m"
   },
   "typeCoverage": {
-    "atLeast": 55.46
+    "atLeast": 54.95
   }
 }
diff --git a/packages/telemetry/package.json b/packages/telemetry/package.json
index a4cf37d3e97..ab45e418d03 100644
--- a/packages/telemetry/package.json
+++ b/packages/telemetry/package.json
@@ -63,6 +63,6 @@
     "workerThreads": false
   },
   "typeCoverage": {
-    "atLeast": 87.07
+    "atLeast": 87.04
   }
 }
diff --git a/packages/telemetry/src/slog-to-otel.js b/packages/telemetry/src/slog-to-otel.js
index 0cadc4911d0..e53583d1b21 100644
--- a/packages/telemetry/src/slog-to-otel.js
+++ b/packages/telemetry/src/slog-to-otel.js
@@ -139,7 +139,10 @@ export const makeSlogToOtelKit = (tracer, overrideAttrs = {}) => {
     serializeBodyFormat: 'smallcaps',
   });
 
-  /** @param {import('@agoric/swingset-vat').SwingSetCapData} data */
+  /**
+   * @param {import('@agoric/swingset-vat').SwingSetCapData} data
+   * @returns {any}
+   */
   const unserialize = data => {
     try {
       const body = rawUnserialize(data);
diff --git a/packages/time/package.json b/packages/time/package.json
index 5f284f9a674..3809a3b1d79 100644
--- a/packages/time/package.json
+++ b/packages/time/package.json
@@ -54,6 +54,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 86.95
+    "atLeast": 87.11
   }
 }
diff --git a/packages/time/src/types.d.ts b/packages/time/src/types.d.ts
index f2efe31c124..d305ae4744e 100644
--- a/packages/time/src/types.d.ts
+++ b/packages/time/src/types.d.ts
@@ -1,6 +1,6 @@
-import type { ERef } from '@endo/eventual-send';
+import type { ERef, RemotableBrand } from '@endo/eventual-send';
 
-import type { RankComparison } from '@endo/marshal';
+import type { RankComparison, RemotableObject } from '@endo/marshal';
 
 /// <reference types="@agoric/notifier/src/types.js"/>
 
@@ -28,7 +28,7 @@ import type { RankComparison } from '@endo/marshal';
  * See https://github.com/Agoric/agoric-sdk/issues/5798
  * and https://github.com/Agoric/agoric-sdk/pull/5821
  */
-export type TimerBrand = {
+export type TimerBrand = RemotableObject & {
   isMyTimerService: (timer: TimerService) => ERef<boolean>;
   isMyClock: (clock: Clock) => ERef<boolean>;
 };
@@ -107,7 +107,7 @@ export type CancelToken = object;
  * schedule a single wake() call, create a repeater that will allow scheduling
  * of events at regular intervals, or remove scheduled calls.
  */
-export interface TimerService {
+export interface TimerServiceI {
   /**
    * Retrieve the latest timestamp
    */
@@ -181,6 +181,10 @@ export interface TimerService {
    */
   getTimerBrand: () => TimerBrand;
 }
+// XXX copied from Remotable helper return type
+export type TimerService = TimerServiceI &
+  RemotableObject<'TimerService'> &
+  RemotableBrand<{}, TimerServiceI>;
 
 /**
  * Read-only access to a TimeService's current time. This allows reading the
diff --git a/packages/vat-data/package.json b/packages/vat-data/package.json
index dbbc8e6750a..b92466dae99 100644
--- a/packages/vat-data/package.json
+++ b/packages/vat-data/package.json
@@ -21,7 +21,6 @@
   "dependencies": {
     "@agoric/assert": "^0.6.0",
     "@agoric/base-zone": "^0.1.0",
-    "@agoric/internal": "^0.3.2",
     "@agoric/store": "^0.9.2",
     "@agoric/swingset-liveslots": "^0.10.2",
     "@agoric/vow": "^0.1.0",
@@ -30,7 +29,6 @@
   },
   "devDependencies": {
     "@endo/init": "^1.1.1",
-    "@endo/far": "^1.1.1",
     "@endo/ses-ava": "^1.2.1",
     "ava": "^5.3.0",
     "tsd": "^0.30.7"
diff --git a/packages/vat-data/src/exo-utils.js b/packages/vat-data/src/exo-utils.js
index a718afa35cc..4c52bf180a7 100644
--- a/packages/vat-data/src/exo-utils.js
+++ b/packages/vat-data/src/exo-utils.js
@@ -5,8 +5,9 @@ import { initEmpty } from '@agoric/store';
 import { provide, VatData as globalVatData } from './vat-data-bindings.js';
 
 /**
- * @import {InterfaceGuard} from '@endo/patterns'
- * @import {Baggage, DefineKindOptions, DurableKindHandle, InterfaceGuardKit} from '@agoric/swingset-liveslots'
+ * @import {InterfaceGuard} from '@endo/patterns';
+ * @import {RemotableObject} from '@endo/pass-style';
+ * @import {Baggage, DefineKindOptions, DurableKindHandle, InterfaceGuardKit} from '@agoric/swingset-liveslots';
  */
 
 /**
@@ -206,7 +207,7 @@ export const makeExoUtils = VatData => {
    * @param {InterfaceGuard | undefined} interfaceGuard
    * @param {I} init
    * @param {T & ThisType<{
-   *   self: T,
+   *   self: RemotableObject & T,
    *   state: ReturnType<I>
    * }>} methods
    * @param {DefineKindOptions<{
diff --git a/packages/vat-data/src/index.test-d.ts b/packages/vat-data/src/index.test-d.ts
index 6f14641539f..4280850379a 100644
--- a/packages/vat-data/src/index.test-d.ts
+++ b/packages/vat-data/src/index.test-d.ts
@@ -14,7 +14,7 @@ import {
   defineDurableKind,
   partialAssign,
   watchPromise,
-} from '.';
+} from './index.js';
 
 // for use in assignments below
 const anyVal = null as any;
diff --git a/packages/vat-data/src/vat-data-bindings.js b/packages/vat-data/src/vat-data-bindings.js
index 39e3b5b759a..f336d606ea0 100644
--- a/packages/vat-data/src/vat-data-bindings.js
+++ b/packages/vat-data/src/vat-data-bindings.js
@@ -9,7 +9,8 @@ import { provideLazy } from '@agoric/store';
 let VatDataGlobal;
 if ('VatData' in globalThis) {
   globalThis.VatData || Fail`VatData defined in global as null or undefined`;
-  VatDataGlobal = globalThis.VatData;
+  // XXX types incompatibility
+  VatDataGlobal = /** @type {any} */ (globalThis.VatData);
 } else {
   // XXX this module has been known to get imported (transitively) in cases that
   // never use it so we make a version that will satisfy module resolution but
diff --git a/packages/vat-data/vow.js b/packages/vat-data/vow.js
index 525a7d1fa41..031568326dc 100644
--- a/packages/vat-data/vow.js
+++ b/packages/vat-data/vow.js
@@ -1,51 +1,2 @@
-/* global globalThis */
-// @ts-check
-import { makeE, prepareVowTools as rawPrepareVowTools } from '@agoric/vow';
-import { makeHeapZone } from '@agoric/base-zone/heap.js';
-import { isUpgradeDisconnection } from '@agoric/internal/src/upgrade-api.js';
-
-/** @type {any} */
-const vatData = globalThis.VatData;
-
-/**
- * Manually-extracted watchPromise so we don't accidentally get the 'unavailable'
- * version.  If it is `undefined`, `@agoric/vow` will shim it.
- * @type {undefined | ((
- *   p: Promise<any>,
- *   watcher: import('@agoric/vow/src/watch-promise.js').PromiseWatcher,
- *   ...args: unknown[]
- * ) => void)}
- */
-const watchPromise = vatData && vatData.watchPromise;
-
-/**
- * Return truthy if a rejection reason should result in a retry.
- * @param {any} reason
- * @returns {boolean}
- */
-const isRetryableReason = reason => isUpgradeDisconnection(reason);
-
-export const defaultPowers = harden({
-  isRetryableReason,
-  watchPromise,
-});
-
-/**
- * @type {typeof rawPrepareVowTools}
- */
-export const prepareVowTools = (zone, powers = {}) =>
-  rawPrepareVowTools(zone, { ...defaultPowers, ...powers });
-
-export const { watch, when, makeVowKit, allVows } =
-  prepareVowTools(makeHeapZone());
-
-/**
- * An vow-shortening E.  CAVEAT: This produces long-lived ephemeral
- * promises that encapsulate the shortening behaviour, and so provides no way
- * for `watch` to durably shorten.  Use the standard `import('@endo/far').E` if
- * you need to `watch` its resulting promises.
- */
-export const V = makeE(globalThis.HandledPromise, {
-  unwrap: when,
-  additional: { when },
-});
+// Backward-compatibility forwarding to the vow package.
+export * from '@agoric/vow/vat.js';
diff --git a/packages/vats/package.json b/packages/vats/package.json
index f0c6eef27d4..83f18f5336a 100644
--- a/packages/vats/package.json
+++ b/packages/vats/package.json
@@ -77,6 +77,6 @@
     "workerThreads": false
   },
   "typeCoverage": {
-    "atLeast": 91.5
+    "atLeast": 91.33
   }
 }
diff --git a/packages/vats/src/core/basic-behaviors.js b/packages/vats/src/core/basic-behaviors.js
index c25922d5ea8..c5cc5dcee13 100644
--- a/packages/vats/src/core/basic-behaviors.js
+++ b/packages/vats/src/core/basic-behaviors.js
@@ -63,6 +63,7 @@ export const makeVatsFromBundles = async ({
   // NOTE: we rely on multiple createVatAdminService calls
   // to return cooperating services.
   const svc = E(vats.vatAdmin).createVatAdminService(devices.vatAdmin);
+  // @ts-expect-error XXX
   vatAdminSvc.resolve(svc);
 
   const durableStore = await vatStore;
@@ -77,6 +78,7 @@ export const makeVatsFromBundles = async ({
         if (bundleName) {
           console.info(`createVatByName(${bundleName})`);
           /** @type {Promise<CreateVatResults>} */
+          // @ts-expect-error XXX
           const vatInfo = E(svc).createVatByName(bundleName, {
             ...defaultVatCreationOptions,
             name: vatName,
@@ -87,6 +89,7 @@ export const makeVatsFromBundles = async ({
         assert(bundleID);
         const bcap = await E(svc).getBundleCap(bundleID);
         /** @type {Promise<CreateVatResults>} */
+        // @ts-expect-error XXX
         const vatInfo = E(svc).createVat(bcap, {
           ...defaultVatCreationOptions,
           name: vatName,
diff --git a/packages/vats/src/core/startWalletFactory.js b/packages/vats/src/core/startWalletFactory.js
index 9b04c34227d..a2dd87df342 100644
--- a/packages/vats/src/core/startWalletFactory.js
+++ b/packages/vats/src/core/startWalletFactory.js
@@ -154,10 +154,12 @@ export const startWalletFactory = async (
     slotToBoardRemote,
   );
 
+  /** @type {() => any} */
   const reviveOldMetrics = () => {
     if (!dataReviver.has(OLD_POOL_METRICS_STORAGE_PATH)) {
       return undefined;
     }
+    /** @type {any} */
     const oldPoolMetrics = dataReviver.getItem(OLD_POOL_METRICS_STORAGE_PATH);
     const newBrandFromOldSlotID = makeMap([
       [oldPoolMetrics.totalMintedProvided.brand.getBoardId(), feeBrand],
diff --git a/packages/vats/src/core/utils.js b/packages/vats/src/core/utils.js
index 4256abf1d13..69b7484cc26 100644
--- a/packages/vats/src/core/utils.js
+++ b/packages/vats/src/core/utils.js
@@ -362,6 +362,7 @@ export const makeVatSpace = (
     {
       get: (_target, name, _rx) => {
         assert.typeof(name, 'string');
+        // @ts-expect-error XXX
         return provideAsync(name, createVatByName).then(vat => {
           if (!durableStore.has(name)) {
             durableStore.init(name, vat);
diff --git a/packages/vats/src/ibc.js b/packages/vats/src/ibc.js
index a1e0e1c9486..504104801c3 100644
--- a/packages/vats/src/ibc.js
+++ b/packages/vats/src/ibc.js
@@ -46,7 +46,11 @@ const DEFAULT_PACKET_TIMEOUT_NS = 60n * 60n * 1_000_000_000n;
  * }} Outbound
  */
 
-/** @param {Zone} zone */
+// FIXME(TS9006) remove 'any'
+/**
+ * @param {Zone} zone
+ * @returns {any}
+ */
 export const prepareIBCConnectionHandler = zone => {
   /**
    * @param {IBCChannelID} channelID
diff --git a/packages/vats/src/lib-board.js b/packages/vats/src/lib-board.js
index 1e655156986..01e8d404062 100644
--- a/packages/vats/src/lib-board.js
+++ b/packages/vats/src/lib-board.js
@@ -15,7 +15,10 @@ import { makeMarshal } from '@endo/marshal';
 
 import { crc6 } from './crc.js';
 
-/** @import {Key} from '@endo/patterns') */
+/**
+ * @import {PassableCap} from '@endo/marshal';
+ * @import {Key} from '@endo/patterns';
+ */
 
 export const DEFAULT_CRC_DIGITS = 2;
 export const DEFAULT_PREFIX = 'board0';
@@ -99,13 +102,13 @@ const initDurableBoardState = (
   const immutable = { prefix, crcDigits };
 
   const lastSequence = BigInt(initSequence);
-  /** @type {MapStore<BoardId, Key>} */
+  /** @type {MapStore<BoardId, PassableCap>} */
   const idToVal = makeScalarBigMapStore('idToVal', {
     durable: true,
     keyShape: IdShape,
     valueShape: ValShape,
   });
-  /** @type {MapStore<Key, BoardId>} */
+  /** @type {MapStore<PassableCap, BoardId>} */
   const valToId = makeScalarBigMapStore('valToId', {
     durable: true,
     keyShape: ValShape,
@@ -127,7 +130,7 @@ const initDurableBoardState = (
 // transient marshallers that get GCed when the function completes.
 
 /**
- * @param {Key} value
+ * @param {PassableCap} value
  * @param {BoardState} state
  */
 const getId = (value, state) => {
@@ -185,7 +188,7 @@ const makeSlotToVal = state => {
   /**
    * @param {BoardId} slot
    * @param {string} iface
-   * @returns {unknown}
+   * @returns {any}
    */
   const slotToVal = (slot, iface) => {
     if (slot !== null) {
@@ -264,7 +267,7 @@ export const prepareBoardKit = baggage => {
          * `value` for its entire lifetime. For a well-known board, this is
          * essentially forever.
          *
-         * @param {Key} value
+         * @param {PassableCap} value
          * @throws if `value` is not a Key in the @agoric/store sense
          */
         getId(value) {
@@ -295,13 +298,14 @@ export const prepareBoardKit = baggage => {
             return board;
           }
           const [first, ...rest] = path;
+          /** @type {any} */
           const firstValue = board.getValue(/** @type {BoardId} */ (first));
           if (rest.length === 0) {
             return firstValue;
           }
           return E(firstValue).lookup(...rest);
         },
-        /** @param {Key} val */
+        /** @param {PassableCap} val */
         has(val) {
           const { state } = this;
           return state.valToId.has(val);
diff --git a/packages/vats/src/nameHub.js b/packages/vats/src/nameHub.js
index 7f767bc6b2f..d93d449fb13 100644
--- a/packages/vats/src/nameHub.js
+++ b/packages/vats/src/nameHub.js
@@ -9,7 +9,7 @@ import {
   prepareGuardedAttenuator,
 } from '@agoric/internal/src/callback.js';
 import { makeHeapZone } from '@agoric/zone';
-import { deeplyFulfilled } from '@endo/marshal';
+import { deeplyFulfilledObject } from '@agoric/internal';
 
 const { Fail, quote: q } = assert;
 
@@ -118,7 +118,7 @@ const updated = (updateCallback, hub, _newValue = undefined) => {
   }
 
   // wait for values to settle before writing
-  return E.when(deeplyFulfilled(hub.entries()), settledEntries =>
+  return E.when(deeplyFulfilledObject(hub.entries()), settledEntries =>
     E(updateCallback).write(settledEntries),
   );
 };
diff --git a/packages/vats/src/types.d.ts b/packages/vats/src/types.d.ts
index 1f33d7c65c2..081567ee76f 100644
--- a/packages/vats/src/types.d.ts
+++ b/packages/vats/src/types.d.ts
@@ -1,3 +1,5 @@
+import type { Guarded } from '@endo/exo';
+
 export type Board = ReturnType<
   ReturnType<typeof import('./lib-board.js').prepareBoardKit>
 >['board'];
@@ -9,7 +11,7 @@ export type Board = ReturnType<
  * allow passing a remote iterable, there would be an inordinate number of round
  * trips for the contents of even the simplest nameHub.
  */
-export type NameHub = {
+export type NameHub<Value = any> = {
   has: (key: string) => boolean;
   /**
    * Look up a path of keys starting from the current NameHub. Wait on any
@@ -17,11 +19,11 @@ export type NameHub = {
    */
   lookup: (...path: string[]) => Promise<any>;
   /** get all the entries available in the current NameHub */
-  entries: (includeReserved?: boolean) => [string, unknown][];
+  entries: (includeReserved?: boolean) => [string, Value][];
   /** get all names available in the current NameHub */
   keys: () => string[];
   /** get all values available in the current NameHub */
-  values: () => unknown[];
+  values: () => Value[];
 };
 
 /** write access to a node in a name hierarchy */
@@ -39,13 +41,13 @@ export type NameAdmin = {
    */
   default: <T>(key: string, newValue: T, newAdmin?: NameAdmin) => T;
   /** Update only if already initialized. Reject if not. */
-  set: (key: string, newValue: unknown, newAdmin?: NameAdmin) => void;
+  set: (key: string, newValue: V, newAdmin?: NameAdmin) => void;
   /**
    * Fulfill an outstanding reserved promise (if any) to the newValue and set
    * the key to the newValue. If newAdmin is provided, set that to return via
    * lookupAdmin.
    */
-  update: (key: string, newValue: unknown, newAdmin?: NameAdmin) => void;
+  update: (key: string, newValue: V, newAdmin?: NameAdmin) => void;
   /**
    * Look up the `newAdmin` from the path of keys starting from the current
    * NameAdmin. Wait on any reserved promises.
@@ -59,7 +61,7 @@ export type NameAdmin = {
 };
 
 export type NameHubUpdateHandler = {
-  write: (entries: [string, unknown][]) => void;
+  write: (entries: [string, V][]) => void;
 };
 
 /** a node in a name hierarchy */
@@ -91,12 +93,12 @@ export type BridgeHandler = {
 };
 
 /** An object which handles messages for a specific bridge */
-export type ScopedBridgeManager = {
+export type ScopedBridgeManager = Guarded<{
   toBridge: (obj: any) => Promise<any>;
   fromBridge: (obj: any) => PromiseVow<void>;
   initHandler: (handler: ERef<BridgeHandler>) => void;
   setHandler: (handler: ERef<BridgeHandler>) => void;
-};
+}>;
 
 /** The object to manage this bridge */
 export type BridgeManager = {
diff --git a/packages/vats/src/vat-bank.js b/packages/vats/src/vat-bank.js
index f81ad6640e6..b9013818d1f 100644
--- a/packages/vats/src/vat-bank.js
+++ b/packages/vats/src/vat-bank.js
@@ -21,6 +21,11 @@ import {
 
 import '@agoric/notifier/exported.js';
 
+/**
+ * @import {Guarded} from '@endo/exo';
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ */
+
 const { Fail } = assert;
 
 const { VirtualPurseControllerI } = makeVirtualPurseKitIKit();
@@ -38,8 +43,9 @@ const BridgeChannelI = M.interface('BridgeChannel', {
  */
 
 /**
- * @typedef {object} BalanceUpdater
- * @property {(value: string, nonce?: string) => void} update
+ * @typedef {Guarded<{
+ *   update: (value: string, nonce?: string) => void;
+ * }>} BalanceUpdater
  */
 
 const BalanceUpdaterI = M.interface('BalanceUpdater', {
@@ -348,8 +354,8 @@ const prepareAssetSubscription = zone => {
 /**
  * @template {AssetKind} [K=AssetKind]
  * @typedef {object} AssetIssuerKit
- * @property {ERef<Mint<K>>} [mint]
- * @property {ERef<Issuer<K>>} issuer
+ * @property {Mint<K>} [mint]
+ * @property {Issuer<K>} issuer
  * @property {Brand<K>} brand
  */
 
@@ -362,12 +368,17 @@ const AssetIssuerKitShape = M.splitRecord(BaseIssuerKitShape, {
   mint: M.remotable('Mint'),
 });
 
-/** @typedef {AssetIssuerKit & { denom: string; escrowPurse?: ERef<Purse> }} AssetRecord */
+/**
+ * @typedef {AssetIssuerKit & {
+ *   denom: string;
+ *   escrowPurse?: RemotableObject & ERef<Purse>;
+ * }} AssetRecord
+ */
 
 /**
  * @typedef {object} AssetDescriptor
  * @property {Brand} brand
- * @property {ERef<Issuer>} issuer
+ * @property {RemotableObject & ERef<Issuer>} issuer
  * @property {string} issuerName
  * @property {string} denom
  * @property {string} proposedName
@@ -411,6 +422,7 @@ const prepareBank = (
   // (which we emulate, since we know both address and denom are JSONable).  If
   // we decide to partition the provider and use `brandToVPurse` directly, we'd
   // need ephemera for each `makeBank` call.
+  /** @type {MapStore<string, VirtualPurse>} */
   const addressDenomToPurse = zone.mapStore('addressDenomToPurse');
   /**
    * @type {import('@agoric/store/src/stores/store-utils.js').AtomicProvider<
@@ -584,7 +596,7 @@ const prepareBankManager = (
       /**
        * @type {MapStore<
        *   string,
-       *   { bank: Bank; brandToVPurse: MapStore<Brand, VirtualPurse> }
+       *   { bank: Guarded<Bank>; brandToVPurse: MapStore<Brand, VirtualPurse> }
        * >}
        */
       const addressToBank = detachedZone.mapStore('addressToBank');
diff --git a/packages/vats/src/virtual-purse.js b/packages/vats/src/virtual-purse.js
index 8f7e1c97fd4..34064e1acfe 100644
--- a/packages/vats/src/virtual-purse.js
+++ b/packages/vats/src/virtual-purse.js
@@ -303,6 +303,7 @@ export const prepareVirtualPurse = zone => {
       recoveryPurse,
       escrowPurse,
     }).purse;
+    // @ts-expect-error XXX
     return vpurse;
   };
 
diff --git a/packages/vats/test/test-bootstrapPayment.js b/packages/vats/test/test-bootstrapPayment.js
index e3555282816..b59f636df00 100644
--- a/packages/vats/test/test-bootstrapPayment.js
+++ b/packages/vats/test/test-bootstrapPayment.js
@@ -10,11 +10,7 @@ import { claim } from '@agoric/ertp/src/legacy-payment-helpers.js';
 import centralSupplyBundle from '../bundles/bundle-centralSupply.js';
 import { feeIssuerConfig } from '../src/core/utils.js';
 
-/**
- * @template T @typedef
- *   {import('@agoric/zoe/src/zoeService/utils.js').Installation<T>}
- *   Installation<T>
- */
+/** @import {Installation} from '@agoric/zoe/src/zoeService/utils.js' */
 /**
  * @typedef {import('ava').ExecutionContext<{
  *   zoe: ZoeService;
diff --git a/packages/vats/test/test-lib-board.js b/packages/vats/test/test-lib-board.js
index e9ec6d264c3..70e90b15949 100644
--- a/packages/vats/test/test-lib-board.js
+++ b/packages/vats/test/test-lib-board.js
@@ -51,6 +51,7 @@ test('makeBoard', async t => {
 test('board values must be scalar keys', async t => {
   const board = makeFakeBoard();
   const nonKey = harden({ a: 1 });
+  // @ts-expect-error intentional error
   await t.throwsAsync(() => E(board).getId(nonKey), {
     message: /arg 0: A "copyRecord" cannot be a scalar key: {"a":1}/,
   });
diff --git a/packages/vats/tools/bank-utils.js b/packages/vats/tools/bank-utils.js
index 13a0047b78c..b0d95423262 100644
--- a/packages/vats/tools/bank-utils.js
+++ b/packages/vats/tools/bank-utils.js
@@ -5,7 +5,7 @@ import { Far } from '@endo/marshal';
 
 /** @param {Pick<IssuerKit, 'brand' | 'issuer'>[]} issuerKits */
 export const makeFakeBankKit = issuerKits => {
-  /** @type {MapStore<Brand, ERef<Issuer>>} */
+  /** @type {MapStore<Brand, Issuer>} */
   const issuers = makeScalarMapStore();
   /**
    * @type {MapStore<
diff --git a/packages/vats/tools/boot-test-utils.js b/packages/vats/tools/boot-test-utils.js
index 09afd1bae01..5730acabfa6 100644
--- a/packages/vats/tools/boot-test-utils.js
+++ b/packages/vats/tools/boot-test-utils.js
@@ -132,6 +132,8 @@ export const makePopulatedFakeVatAdmin = () => {
     return createVat(fakeNameToCap.get(name) || Fail`unknown vat ${name}`);
   };
 
+  // FIXME(TS9006) remove 'any'
+  /** @type {any} */
   const vatAdminService = Far('vatAdminSvc', {
     ...fakeVatAdmin,
     createVat,
diff --git a/packages/vow/README.md b/packages/vow/README.md
index a0495b84f49..b34dc1db902 100644
--- a/packages/vow/README.md
+++ b/packages/vow/README.md
@@ -26,12 +26,12 @@ Here they are: {
 }
 ```
 
-On Agoric, you can use `V` exported from `@agoric/vat-data/vow.js`, which
+On Agoric, you can use `V` exported from `@agoric/vow/vat.js`, which
 converts a chain of promises and vows to a promise for its final
 fulfilment, by unwrapping any intermediate vows:
 
 ```js
-import { V as E } from '@agoric/vat-data/vow.js';
+import { V as E } from '@agoric/vow/vat.js';
 [...]
 const a = await E.when(w1);
 const b = await E(w2).something(...args);
@@ -45,7 +45,7 @@ On Agoric, use the following to create and resolve a vow:
 ```js
 // CAVEAT: `V` uses internal ephemeral promises, so while it is convenient,
 // it cannot be used by upgradable vats.  See "Durability" below:
-import { V as E, makeVowKit } from '@agoric/vat-data/vow.js';
+import { V as E, makeVowKit } from '@agoric/vow/vat.js';
 [...]
 const { resolver, vow } = makeVowKit();
 // Send vow to a potentially different vat.
@@ -56,16 +56,15 @@ resolver.resolve('now you know the answer');
 
 ## Durability
 
-The vow package supports Zones, which are used to integrate Agoric's vat
-upgrade mechanism and `watchPromise`.  To create vow tools that deal with
-durable objects:
+The `@agoric/vow/vat.js` module allows vows to integrate Agoric's vat upgrade
+mechanism.  To create vow tools that deal with durable objects:
 
 ```js
 // NOTE: Cannot use `V` as it has non-durable internal state when unwrapping
 // vows.  Instead, use the default vow-exposing `E` with the `watch`
 // operator.
 import { E } from '@endo/far';
-import { prepareVowTools } from '@agoric/vat-data/vow.js';
+import { prepareVowTools } from '@agoric/vow/vat.js';
 import { makeDurableZone } from '@agoric/zone';
 
 // Only do the following once at the start of a new vat incarnation:
diff --git a/packages/vow/package.json b/packages/vow/package.json
index 722f1bbc5c3..f346e36aa9c 100755
--- a/packages/vow/package.json
+++ b/packages/vow/package.json
@@ -21,6 +21,7 @@
   },
   "dependencies": {
     "@agoric/base-zone": "^0.1.0",
+    "@agoric/internal": "^0.3.2",
     "@endo/env-options": "^1.1.3",
     "@endo/eventual-send": "^1.2.1",
     "@endo/pass-style": "^1.3.1",
@@ -28,7 +29,6 @@
     "@endo/promise-kit": "^1.1.1"
   },
   "devDependencies": {
-    "@agoric/internal": "^0.3.2",
     "@endo/far": "^1.1.1",
     "@endo/init": "^1.1.1",
     "ava": "^5.3.0"
@@ -47,6 +47,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 89.21
+    "atLeast": 89.38
   }
 }
diff --git a/packages/vow/src/tools.js b/packages/vow/src/tools.js
index 7d0b93f7606..6ca442b7c88 100644
--- a/packages/vow/src/tools.js
+++ b/packages/vow/src/tools.js
@@ -8,13 +8,12 @@ import { prepareWatchUtils } from './watch-utils.js';
  * @param {import('@agoric/base-zone').Zone} zone
  * @param {object} [powers]
  * @param {(reason: any) => boolean} [powers.isRetryableReason]
- * @param {(p: PromiseLike<any>, watcher: import('./watch-promise.js').PromiseWatcher, ...args: unknown[]) => void} [powers.watchPromise]
  */
 export const prepareVowTools = (zone, powers = {}) => {
-  const { isRetryableReason = () => false, watchPromise } = powers;
-  const makeVowKit = prepareVowKit(zone, watchPromise);
+  const { isRetryableReason = () => false } = powers;
+  const makeVowKit = prepareVowKit(zone);
   const when = makeWhen(isRetryableReason);
-  const watch = prepareWatch(zone, makeVowKit, watchPromise, isRetryableReason);
+  const watch = prepareWatch(zone, makeVowKit, isRetryableReason);
   const makeWatchUtils = prepareWatchUtils(zone, watch, makeVowKit);
   const watchUtils = makeWatchUtils();
 
diff --git a/packages/vow/src/types.js b/packages/vow/src/types.js
index ad582399cb5..dfc1bd4c5bb 100644
--- a/packages/vow/src/types.js
+++ b/packages/vow/src/types.js
@@ -1,6 +1,11 @@
 // @ts-check
 export {};
 
+/**
+ * @import {Passable, RemotableObject} from '@endo/pass-style';
+ * @import {PromiseVow, Remote} from '@agoric/vow';
+ */
+
 /** @typedef {(...args: any[]) => any} Callable */
 
 /**
@@ -77,7 +82,7 @@ export {};
 /**
  * @template [T=any]
  * @typedef {object} VowPayload
- * @property {Remote<VowV0<T>>} vowV0
+ * @property {RemotableObject & Remote<VowV0<T>>} vowV0
  */
 
 /**
diff --git a/packages/vow/src/vow.js b/packages/vow/src/vow.js
index 21e6f286cc5..544b53011ce 100644
--- a/packages/vow/src/vow.js
+++ b/packages/vow/src/vow.js
@@ -2,7 +2,7 @@
 import { makePromiseKit } from '@endo/promise-kit';
 import { M } from '@endo/patterns';
 import { makeTagged } from '@endo/pass-style';
-import { PromiseWatcherI, watchPromiseShim } from './watch-promise.js';
+import { PromiseWatcherI } from '@agoric/base-zone';
 
 const sink = () => {};
 harden(sink);
@@ -14,9 +14,8 @@ harden(sink);
 
 /**
  * @param {import('@agoric/base-zone').Zone} zone
- * @param {typeof watchPromiseShim} [watchPromise]
  */
-export const prepareVowKit = (zone, watchPromise = watchPromiseShim) => {
+export const prepareVowKit = zone => {
   /** @type {WeakMap<import('./types.js').VowResolver, VowEphemera>} */
   const resolverToEphemera = new WeakMap();
 
@@ -94,7 +93,7 @@ export const prepareVowKit = (zone, watchPromise = watchPromiseShim) => {
           const { promise, resolve } = getPromiseKitForResolution(resolver);
           if (resolve) {
             resolve(value);
-            watchPromise(promise, this.facets.watchNextStep);
+            zone.watchPromise(promise, this.facets.watchNextStep);
           }
         },
         /**
diff --git a/packages/vow/src/watch.js b/packages/vow/src/watch.js
index b28e3c3a005..91b1d38843a 100644
--- a/packages/vow/src/watch.js
+++ b/packages/vow/src/watch.js
@@ -1,21 +1,21 @@
 // @ts-check
+import { PromiseWatcherI } from '@agoric/base-zone';
 import { getVowPayload, basicE } from './vow-utils.js';
-import { PromiseWatcherI, watchPromiseShim } from './watch-promise.js';
 
 const { apply } = Reflect;
 
 /**
- * @param {typeof watchPromiseShim} watchPromise
+ * @param {import('@agoric/base-zone').Zone} zone
  */
 const makeWatchNextStep =
-  watchPromise =>
+  zone =>
   /**
    * If the specimen is a vow, obtain a fresh shortened promise from it,
    * otherwise coerce the non-vow specimen to a promise.  Then, associate a
    * (usually durable) watcher object with the promise.
    *
    * @param {any} specimen
-   * @param {import('./watch-promise.js').PromiseWatcher} promiseWatcher
+   * @param {import('@agoric/base-zone').PromiseWatcher} promiseWatcher
    */
   (specimen, promiseWatcher) => {
     let promise;
@@ -25,7 +25,7 @@ const makeWatchNextStep =
     } else {
       promise = basicE.resolve(specimen);
     }
-    watchPromise(promise, promiseWatcher);
+    zone.watchPromise(promise, promiseWatcher);
   };
 
 /**
@@ -82,7 +82,7 @@ const preparePromiseWatcher = (zone, isRetryableReason, watchNextStep) =>
       return /** @type {Partial<typeof state>} */ (state);
     },
     {
-      /** @type {Required<import('./watch-promise.js').PromiseWatcher>['onFulfilled']} */
+      /** @type {Required<import('@agoric/base-zone').PromiseWatcher>['onFulfilled']} */
       onFulfilled(value) {
         const { watcher, watcherContext, resolver } = this.state;
         if (getVowPayload(value)) {
@@ -95,7 +95,7 @@ const preparePromiseWatcher = (zone, isRetryableReason, watchNextStep) =>
         this.state.resolver = undefined;
         settle(resolver, watcher, 'onFulfilled', value, watcherContext);
       },
-      /** @type {Required<import('./watch-promise.js').PromiseWatcher>['onRejected']} */
+      /** @type {Required<import('@agoric/base-zone').PromiseWatcher>['onRejected']} */
       onRejected(reason) {
         const { vow, watcher, watcherContext, resolver } = this.state;
         if (vow && isRetryableReason(reason)) {
@@ -112,16 +112,14 @@ const preparePromiseWatcher = (zone, isRetryableReason, watchNextStep) =>
 /**
  * @param {import('@agoric/base-zone').Zone} zone
  * @param {() => import('./types.js').VowKit<any>} makeVowKit
- * @param {typeof watchPromiseShim} [watchPromise]
  * @param {(reason: any) => boolean} [isRetryableReason]
  */
 export const prepareWatch = (
   zone,
   makeVowKit,
-  watchPromise = watchPromiseShim,
   isRetryableReason = _reason => false,
 ) => {
-  const watchNextStep = makeWatchNextStep(watchPromise);
+  const watchNextStep = makeWatchNextStep(zone);
   const makePromiseWatcher = preparePromiseWatcher(
     zone,
     isRetryableReason,
@@ -150,7 +148,7 @@ export const prepareWatch = (
     );
 
     // Coerce the specimen to a promise, and start the watcher cycle.
-    watchPromise(basicE.resolve(specimenP), promiseWatcher);
+    zone.watchPromise(basicE.resolve(specimenP), promiseWatcher);
 
     return vow;
   };
diff --git a/packages/vat-data/test/test-vow.js b/packages/vow/test/test-vat.js
similarity index 96%
rename from packages/vat-data/test/test-vow.js
rename to packages/vow/test/test-vat.js
index e21e0d14ff2..bbb04e0452b 100644
--- a/packages/vat-data/test/test-vow.js
+++ b/packages/vow/test/test-vat.js
@@ -2,7 +2,7 @@
 import test from 'ava';
 import { E, Far } from '@endo/far';
 
-import { V, makeVowKit } from '../vow.js';
+import { V, makeVowKit } from '../vat.js';
 
 test('heap messages', async t => {
   const greeter = Far('Greeter', {
diff --git a/packages/vow/vat.js b/packages/vow/vat.js
new file mode 100644
index 00000000000..f4d268f3166
--- /dev/null
+++ b/packages/vow/vat.js
@@ -0,0 +1,36 @@
+/* global globalThis */
+// @ts-check
+import { isUpgradeDisconnection } from '@agoric/internal/src/upgrade-api.js';
+import { makeHeapZone } from '@agoric/base-zone/heap.js';
+import { makeE, prepareVowTools as rawPrepareVowTools } from './src/index.js';
+
+/**
+ * Return truthy if a rejection reason should result in a retry.
+ * @param {any} reason
+ * @returns {boolean}
+ */
+const isRetryableReason = reason => isUpgradeDisconnection(reason);
+
+export const defaultPowers = harden({
+  isRetryableReason,
+});
+
+/**
+ * @type {typeof rawPrepareVowTools}
+ */
+export const prepareVowTools = (zone, powers = {}) =>
+  rawPrepareVowTools(zone, { ...defaultPowers, ...powers });
+
+export const { watch, when, makeVowKit, allVows } =
+  prepareVowTools(makeHeapZone());
+
+/**
+ * A vow-shortening E.  CAVEAT: This produces long-lived ephemeral
+ * promises that encapsulate the shortening behaviour, and so provides no way
+ * for `watch` to durably shorten.  Use the standard `import('@endo/far').E` if
+ * you need to `watch` its resulting promises.
+ */
+export const V = makeE(globalThis.HandledPromise, {
+  unwrap: when,
+  additional: { when },
+});
diff --git a/packages/wallet/api/src/internal-types.js b/packages/wallet/api/src/internal-types.js
index c08258b5642..12c34f82190 100644
--- a/packages/wallet/api/src/internal-types.js
+++ b/packages/wallet/api/src/internal-types.js
@@ -7,7 +7,10 @@
  * @property {PurseActions} actions
  */
 
-/** @import {Petname} from '@agoric/deploy-script-support/src/externalTypes.js' */
+/**
+ * @import {Petname} from '@agoric/deploy-script-support/src/externalTypes.js';
+ * @import {Key} from '@endo/patterns';
+ */
 
 /**
  * @typedef {PursesJSONState & PursesAddedState} PursesFullState
@@ -51,7 +54,7 @@
  */
 
 /**
- * @template T
+ * @template {Key} T
  * @typedef {object} Mapping
  * @property {(petname: Petname) => string} implode
  * @property {(str: string) => Petname} explode
diff --git a/packages/wallet/api/src/lib-dehydrate.js b/packages/wallet/api/src/lib-dehydrate.js
index 55d0209fe6b..b4f7defb55e 100644
--- a/packages/wallet/api/src/lib-dehydrate.js
+++ b/packages/wallet/api/src/lib-dehydrate.js
@@ -86,10 +86,9 @@ export const makeDehydrator = (initialUnnamedCount = 0) => {
   };
 
   /**
-   * @template T
    * @param {string} kind
    * @param {{ useLegacyMap?: boolean }} [legacyOptions]
-   * @returns {Mapping<T>}
+   * @returns {Mapping<any>}
    */
   const makeMapping = (kind, { useLegacyMap = false } = {}) => {
     typeof kind === 'string' || `kind ${kind} must be a string`;
@@ -97,9 +96,9 @@ export const makeDehydrator = (initialUnnamedCount = 0) => {
     // These are actually either a LegacyMap or a MapStore depending on
     // useLegacyMap. Fortunately, the LegacyMap type is approximately the
     // intersection of these, so we can just use it.
-    /** @type {LegacyMap<T, string>} */
+    /** @type {LegacyMap<any, string>} */
     const rawValToPetname = makeMap('value');
-    /** @type {LegacyMap<T, string | Path>} */
+    /** @type {LegacyMap<any, string | Path>} */
     const valToPetname = {
       ...rawValToPetname,
       set(key, val) {
@@ -121,9 +120,9 @@ export const makeDehydrator = (initialUnnamedCount = 0) => {
         return mapIterable(rawValToPetname.values(), val => explode(val));
       },
     };
-    /** @type {MapStore<string, T>} */
+    /** @type {MapStore<string, any>} */
     const rawPetnameToVal = makeScalarMapStore('petname');
-    /** @type {MapStore<Path | string, T>} */
+    /** @type {MapStore<Path | string, any>} */
     const petnameToVal = {
       ...rawPetnameToVal,
       init(key, val) {
@@ -270,7 +269,7 @@ export const makeDehydrator = (initialUnnamedCount = 0) => {
       petnameToVal.delete(petname);
       valToPetname.delete(val);
     };
-    /** @type {Mapping<T>} */
+    /** @type {Mapping<any>} */
     const mapping = harden({
       implode,
       explode,
diff --git a/packages/wallet/api/src/lib-wallet.js b/packages/wallet/api/src/lib-wallet.js
index d94f1262397..50793f3fc3e 100644
--- a/packages/wallet/api/src/lib-wallet.js
+++ b/packages/wallet/api/src/lib-wallet.js
@@ -754,7 +754,9 @@ export function makeWalletRoot({
    * @param {string} [address]
    */
   const addContact = async (petname, actions, address = undefined) => {
+    // @ts-expect-error XXX ERef
     const already = await E(board).has(actions);
+    /** @type {any} */
     let depositFacet;
     if (already) {
       depositFacet = actions;
diff --git a/packages/xsnap-lockdown/package.json b/packages/xsnap-lockdown/package.json
index 891e539c560..679a311369c 100644
--- a/packages/xsnap-lockdown/package.json
+++ b/packages/xsnap-lockdown/package.json
@@ -25,7 +25,8 @@
     "ava": "^5.3.0",
     "c8": "^9.1.0",
     "rollup": "^2.58.0",
-    "rollup-plugin-string": "^3.0.0"
+    "rollup-plugin-string": "^3.0.0",
+    "source-map": "^0.7.4"
   },
   "files": [
     "LICENSE*",
diff --git a/packages/zoe/package.json b/packages/zoe/package.json
index e5f3699fce0..3cf2fb7d911 100644
--- a/packages/zoe/package.json
+++ b/packages/zoe/package.json
@@ -139,6 +139,6 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 84.9
+    "atLeast": 84.91
   }
 }
diff --git a/packages/zoe/src/cleanProposal.js b/packages/zoe/src/cleanProposal.js
index 94b5ffc4052..37fd8bef2bd 100644
--- a/packages/zoe/src/cleanProposal.js
+++ b/packages/zoe/src/cleanProposal.js
@@ -57,6 +57,7 @@ export const coerceAmountPatternKeywordRecord = (
   getAssetKindByBrand,
 ) => {
   cleanKeywords(allegedAmountKeywordRecord);
+  // FIXME objectMap should constrain the mapping function by the record's type
   return objectMap(allegedAmountKeywordRecord, amount => {
     // Check that each value can be coerced using the AmountMath
     // indicated by brand. `AmountMath.coerce` throws if coercion fails.
@@ -75,6 +76,12 @@ export const coerceAmountPatternKeywordRecord = (
   });
 };
 
+/**
+ *
+ * @param {unknown} allegedAmountKeywordRecord
+ * @param {*} getAssetKindByBrand
+ * @returns {AmountKeywordRecord}
+ */
 export const coerceAmountKeywordRecord = (
   allegedAmountKeywordRecord,
   getAssetKindByBrand,
@@ -84,6 +91,7 @@ export const coerceAmountKeywordRecord = (
     getAssetKindByBrand,
   );
   assertKey(result);
+  // @ts-expect-error checked cast
   return result;
 };
 
diff --git a/packages/zoe/src/contractFacet/offerHandlerStorage.js b/packages/zoe/src/contractFacet/offerHandlerStorage.js
index 09e2d30bd75..26ff65aaff1 100644
--- a/packages/zoe/src/contractFacet/offerHandlerStorage.js
+++ b/packages/zoe/src/contractFacet/offerHandlerStorage.js
@@ -6,9 +6,18 @@ import { canBeDurable, provideDurableWeakMapStore } from '@agoric/vat-data';
 
 import { defineDurableHandle } from '../makeHandle.js';
 
+/**
+ * @import {RemotableBrand} from '@endo/eventual-send';
+ * @import {RemotableObject} from '@endo/pass-style';
+ */
+
+/**
+ * @typedef {RemotableBrand & RemotableObject & OfferHandler} PassableOfferHandler
+ */
+
 export const makeOfferHandlerStorage = zcfBaggage => {
   const makeInvitationHandle = defineDurableHandle(zcfBaggage, 'Invitation');
-  /** @type {WeakMapStore<InvitationHandle, OfferHandler>} */
+  /** @type {WeakMapStore<InvitationHandle, PassableOfferHandler>} */
 
   // ZCF needs to ephemerally hold on to ephemeral handlers, and durably hold
   // onto handlers that are intended to be durable. We keep two stores and store
@@ -18,13 +27,12 @@ export const makeOfferHandlerStorage = zcfBaggage => {
   const invitationHandleToEphemeralHandler = makeScalarWeakMapStore(
     'invitationHandleToEphemeralHandler',
   );
-  /** @type {WeakMapStore<InvitationHandle, OfferHandler>} */
+  /** @type {WeakMapStore<InvitationHandle, PassableOfferHandler>} */
   const invitationHandleToDurableHandler = provideDurableWeakMapStore(
     zcfBaggage,
     'invitationHandleToDurableHandler',
   );
 
-  /** @type {(offerHandler: OfferHandler) => InvitationHandle} */
   const storeOfferHandler = offerHandler => {
     if (typeof offerHandler === 'function') {
       offerHandler = ToFarFunction('offerHandler', offerHandler);
diff --git a/packages/zoe/src/contractFacet/types-ambient.d.ts b/packages/zoe/src/contractFacet/types-ambient.d.ts
index 858a1c89f3d..2dfadbe3be3 100644
--- a/packages/zoe/src/contractFacet/types-ambient.d.ts
+++ b/packages/zoe/src/contractFacet/types-ambient.d.ts
@@ -6,6 +6,8 @@ type IssuerOptionsRecord = import('@agoric/ertp').IssuerOptionsRecord;
 type Completion = any;
 type ZCFMakeEmptySeatKit = (exit?: ExitRule | undefined) => ZcfSeatKit;
 
+type InvitationAmount = Amount<'set', InvitationDetails>;
+
 /**
  * Zoe Contract Facet
  *
@@ -38,10 +40,10 @@ type ZCF<CT extends unknown = Record<string, unknown>> = {
    * @returns the AmountMath and brand synchronously accessible after
    * saving
    */
-  saveIssuer: (
-    issuerP: ERef<Issuer>,
+  saveIssuer: <I extends Issuer>(
+    issuerP: ERef<I>,
     keyword: Keyword,
-  ) => Promise<IssuerRecord<any>>;
+  ) => Promise<I extends Issuer<infer K, infer M> ? IssuerRecord<K, M> : never>;
 
   /**
    * Make a credible Zoe invitation for a particular smart contract
@@ -162,7 +164,7 @@ type ZCFMint<K extends AssetKind = AssetKind> = {
  * normally an instanceof Error.
  */
 type ZCFSeatFail = (reason: unknown) => Error;
-type ZCFSeat = {
+type ZCFSeat = import('@endo/pass-style').RemotableObject & {
   exit: (completion?: Completion) => void;
   fail: ZCFSeatFail;
   getSubscriber: () => Promise<Subscriber<Allocation>>;
@@ -243,7 +245,10 @@ type AdminFacet = import('../zoeService/utils').AdminFacet<any>;
 
 declare const OfferReturn: unique symbol;
 declare const OfferArgs: unique symbol;
-type Invitation<R = unknown, A = undefined> = Payment<'set'> & {
+type Invitation<R = unknown, A = undefined> = Payment<
+  'set',
+  InvitationDetails
+> & {
   // because TS is structural, without this the generic is ignored
   [OfferReturn]?: R;
   [OfferArgs]?: A;
diff --git a/packages/zoe/src/contractFacet/zcfMint.js b/packages/zoe/src/contractFacet/zcfMint.js
index 4522559be23..7fbd2772b72 100644
--- a/packages/zoe/src/contractFacet/zcfMint.js
+++ b/packages/zoe/src/contractFacet/zcfMint.js
@@ -15,10 +15,9 @@ import './types-ambient.js';
 const { Fail } = assert;
 
 /**
- * @template {AssetKind} K
  * @param {AmountKeywordRecord} amr
- * @param {IssuerRecord<K>} issuerRecord
- * @returns {Amount<K>}
+ * @param {IssuerRecord} issuerRecord
+ * @returns {Amount}
  */
 export const sumAmountKeywordRecord = (amr, issuerRecord) => {
   const empty = AmountMath.makeEmpty(
diff --git a/packages/zoe/src/contractFacet/zcfSeat.js b/packages/zoe/src/contractFacet/zcfSeat.js
index 9658f66512f..452477c943d 100644
--- a/packages/zoe/src/contractFacet/zcfSeat.js
+++ b/packages/zoe/src/contractFacet/zcfSeat.js
@@ -206,7 +206,7 @@ export const createSeatManager = (
         assertActive(self);
         const currentAllocation = getCurrentAllocation(self);
         if (currentAllocation[keyword] !== undefined) {
-          // @ts-expect-error cast
+          // @ts-expect-error never checks brand
           return currentAllocation[keyword];
         }
         if (!brand) {
diff --git a/packages/zoe/src/contractSupport/durability.js b/packages/zoe/src/contractSupport/durability.js
index 644d54401d1..878c5380765 100644
--- a/packages/zoe/src/contractSupport/durability.js
+++ b/packages/zoe/src/contractSupport/durability.js
@@ -8,7 +8,7 @@ import { E } from '@endo/eventual-send';
  * representative also remains.
  *
  * @template {{}} E Ephemeral state
- * @template {{}} [K=any] key on which to provision
+ * @template {WeakKey} K key on which to provision
  * @param {(key: K) => E} init
  */
 export const makeEphemeraProvider = init => {
diff --git a/packages/zoe/src/contractSupport/priceAuthority.js b/packages/zoe/src/contractSupport/priceAuthority.js
index a3510f7eb23..ba779438a94 100644
--- a/packages/zoe/src/contractSupport/priceAuthority.js
+++ b/packages/zoe/src/contractSupport/priceAuthority.js
@@ -65,7 +65,7 @@ export const PriceAuthorityI = M.interface('PriceAuthority', {
 
 /**
  * @param {object} opts
- * @param {Issuer<'set'>} opts.quoteIssuer
+ * @param {Issuer<'set', PriceDescription>} opts.quoteIssuer
  * @param {ERef<Notifier<unknown>>} opts.notifier
  * @param {ERef<import('@agoric/time').TimerService>} opts.timer
  * @param {PriceQuoteCreate} opts.createQuote
diff --git a/packages/zoe/src/contractSupport/priceAuthorityInitial.js b/packages/zoe/src/contractSupport/priceAuthorityInitial.js
index 273d375729d..30bf5038158 100644
--- a/packages/zoe/src/contractSupport/priceAuthorityInitial.js
+++ b/packages/zoe/src/contractSupport/priceAuthorityInitial.js
@@ -23,7 +23,7 @@ import { mintQuote } from './priceAuthorityTransform.js';
  *
  * @param {Ratio} priceOutPerIn
  * @param {PriceAuthority} priceAuthority
- * @param {ERef<Mint<'set'>>} quoteMint
+ * @param {ERef<Mint<'set', PriceDescription>>} quoteMint
  * @param {Brand<'nat'>} brandIn
  * @param {Brand<'nat'>} brandOut
  * @returns {PriceAuthority}
diff --git a/packages/zoe/src/contractSupport/priceAuthorityQuoteMint.js b/packages/zoe/src/contractSupport/priceAuthorityQuoteMint.js
index 46531ffc125..de26f9bb0c3 100644
--- a/packages/zoe/src/contractSupport/priceAuthorityQuoteMint.js
+++ b/packages/zoe/src/contractSupport/priceAuthorityQuoteMint.js
@@ -1,16 +1,23 @@
 import { AssetKind, prepareIssuerKit } from '@agoric/ertp';
 import { provideDurableMapStore } from '@agoric/vat-data';
 
+/**
+ * @import {EOnly} from '@endo/eventual-send';
+ * @import {MutableQuote, PriceAuthority, PriceDescription, PriceQuote, PriceQuoteValue, PriceQuery,} from '@agoric/zoe/tools/types.js';
+ */
+
 /**
  *
  * @param {import('@agoric/vat-data').Baggage} baggage
- * @returns {ERef<Mint<'set'>>}
+ * @returns {ERef<Mint<'set', PriceDescription>>}
  */
 export const provideQuoteMint = baggage => {
   const issuerBaggage = provideDurableMapStore(
     baggage,
     'quoteMintIssuerBaggage',
   );
+  /** @type {IssuerKit<'set', PriceDescription>} */
+  // @ts-expect-error cast
   const issuerKit = prepareIssuerKit(
     issuerBaggage,
     'quote',
diff --git a/packages/zoe/src/contractSupport/priceAuthorityTransform.js b/packages/zoe/src/contractSupport/priceAuthorityTransform.js
index 2744c599876..fbfd509c707 100644
--- a/packages/zoe/src/contractSupport/priceAuthorityTransform.js
+++ b/packages/zoe/src/contractSupport/priceAuthorityTransform.js
@@ -6,16 +6,16 @@ import { makeNotifier } from '@agoric/notifier';
 
 /**
  * @import {EOnly} from '@endo/eventual-send';
- * @import {MutableQuote, PriceAuthority, PriceQuote, PriceQuoteValue, PriceQuery,} from '@agoric/zoe/tools/types.js';
+ * @import {MutableQuote, PriceAuthority, PriceQuote, PriceDescription,} from '@agoric/zoe/tools/types.js';
  */
 
 /**
  * @param {Brand<'set'>} quoteBrand
  * @param {Amount<'nat'>} amountIn
  * @param {Amount<'nat'>} amountOut
- * @param {ERef<import('@agoric/time').TimerService>} timer
- * @param {import('@agoric/time').Timestamp} timestamp
- * @param {ERef<Mint<'set'>>} quoteMint
+ * @param {import('@agoric/time').TimerService} timer
+ * @param {import('@agoric/time').TimestampRecord} timestamp
+ * @param {ERef<Mint<'set', PriceDescription>>} quoteMint
  * @returns {Promise<PriceQuote>}
  */
 export const mintQuote = async (
@@ -39,7 +39,7 @@ export const mintQuote = async (
 
 /**
  * @param {object} opts
- * @param {ERef<Mint<'set'>>} opts.quoteMint
+ * @param {ERef<Mint<'set', PriceDescription>>} opts.quoteMint
  * @param {ERef<PriceAuthority>} opts.sourcePriceAuthority
  * @param {Brand<'nat'>} opts.sourceBrandIn
  * @param {Brand<'nat'>} opts.sourceBrandOut
diff --git a/packages/zoe/src/contractSupport/ratio.js b/packages/zoe/src/contractSupport/ratio.js
index c4659aa968b..7635ce7d7b8 100644
--- a/packages/zoe/src/contractSupport/ratio.js
+++ b/packages/zoe/src/contractSupport/ratio.js
@@ -70,7 +70,6 @@ export const makeRatio = (
   denominator > 0n ||
     Fail`No infinite ratios! Denominator was 0 ${q(denominatorBrand)}`;
 
-  // @ts-expect-error cast to return type because make() ensures
   return harden({
     numerator: AmountMath.make(numeratorBrand, numerator),
     denominator: AmountMath.make(denominatorBrand, denominator),
@@ -98,6 +97,7 @@ export const makeRatioFromAmounts = (numeratorAmount, denominatorAmount) => {
  * @param {Amount<'nat'>} amount
  * @param {Ratio} ratio
  * @param {*} divideOp
+ * @returns {Amount<'nat'>}
  */
 const multiplyHelper = (amount, ratio, divideOp) => {
   AmountMath.coerce(amount.brand, amount);
@@ -107,12 +107,14 @@ const multiplyHelper = (amount, ratio, divideOp) => {
       ratio.denominator.brand,
     )}`;
 
-  return AmountMath.make(
-    ratio.numerator.brand,
-    divideOp(
-      multiply(amount.value, ratio.numerator.value),
-      ratio.denominator.value,
-    ),
+  return /** @type {Amount<'nat'>} */ (
+    AmountMath.make(
+      ratio.numerator.brand,
+      divideOp(
+        multiply(amount.value, ratio.numerator.value),
+        ratio.denominator.value,
+      ),
+    )
   );
 };
 
@@ -135,6 +137,7 @@ export const multiplyBy = (amount, ratio) => {
  * @param {Amount<'nat'>} amount
  * @param {Ratio} ratio
  * @param {*} divideOp
+ * @returns {Amount<'nat'>}
  */
 const divideHelper = (amount, ratio, divideOp) => {
   AmountMath.coerce(amount.brand, amount);
@@ -144,12 +147,14 @@ const divideHelper = (amount, ratio, divideOp) => {
       ratio.numerator.brand,
     )}`;
 
-  return AmountMath.make(
-    ratio.denominator.brand,
-    divideOp(
-      multiply(amount.value, ratio.denominator.value),
-      ratio.numerator.value,
-    ),
+  return /** @type {Amount<'nat'>} */ (
+    AmountMath.make(
+      ratio.denominator.brand,
+      divideOp(
+        multiply(amount.value, ratio.denominator.value),
+        ratio.numerator.value,
+      ),
+    )
   );
 };
 
diff --git a/packages/zoe/src/contractSupport/recorder.js b/packages/zoe/src/contractSupport/recorder.js
index 6e81830902b..7c9e63f7536 100644
--- a/packages/zoe/src/contractSupport/recorder.js
+++ b/packages/zoe/src/contractSupport/recorder.js
@@ -94,7 +94,7 @@ export const prepareRecorder = (baggage, marshaller) => {
       /**
        * Marshalls before writing to storage or publisher to help ensure the two streams match.
        *
-       * @param {unknown} value
+       * @param {any} value
        * @returns {Promise<void>}
        */
       async write(value) {
@@ -111,7 +111,7 @@ export const prepareRecorder = (baggage, marshaller) => {
       /**
        * Like `write` but prevents future writes and terminates the publisher.
        *
-       * @param {unknown} value
+       * @param {any} value
        * @returns {Promise<void>}
        */
       async writeFinal(value) {
@@ -267,7 +267,7 @@ export const prepareMockRecorderKitMakers = () => {
  * whole thing to `any`.
  *
  * @template T
- * @typedef {{ validatedType?: T }} TypedMatcher
+ * @typedef {import('@endo/patterns').Matcher & { validatedType?: T }} TypedMatcher
  */
 
 /**
diff --git a/packages/zoe/src/contracts/autoswap.js b/packages/zoe/src/contracts/autoswap.js
index 1b9f58f40a3..40939bbf65d 100644
--- a/packages/zoe/src/contracts/autoswap.js
+++ b/packages/zoe/src/contracts/autoswap.js
@@ -274,8 +274,10 @@ const start = async zcf => {
     });
 
     // TODO (hibbert) should we burn tokens?
-    const userAllocation = removeLiqSeat.getCurrentAllocation();
-    /** @type {Amount<'nat'>} */
+
+    const userAllocation = /** @type {{Liquidity: Amount<'nat'>}} */ (
+      removeLiqSeat.getCurrentAllocation()
+    );
     const liquidityIn = userAllocation.Liquidity;
     assert(!AmountMath.isEmpty(liquidityIn), 'Pool is empty');
     const liquidityValueIn = liquidityIn.value;
diff --git a/packages/zoe/src/contracts/callSpread/pricedCallSpread.js b/packages/zoe/src/contracts/callSpread/pricedCallSpread.js
index 67cc94c23a6..451170bb31d 100644
--- a/packages/zoe/src/contracts/callSpread/pricedCallSpread.js
+++ b/packages/zoe/src/contracts/callSpread/pricedCallSpread.js
@@ -104,6 +104,7 @@ const start = zcf => {
     const invitationIssuer = zcf.getInvitationIssuer();
     const payment = harden({ Option: option });
     const Option = await E(invitationIssuer).getAmountOf(option);
+    /** @type {any} */
     const spreadAmount = harden({
       Option,
     });
diff --git a/packages/zoe/src/contracts/loan/borrow.js b/packages/zoe/src/contracts/loan/borrow.js
index 5a07165fd01..af720c00e9d 100644
--- a/packages/zoe/src/contracts/loan/borrow.js
+++ b/packages/zoe/src/contracts/loan/borrow.js
@@ -39,7 +39,9 @@ export const makeBorrowInvitation = (zcf, config) => {
 
     const collateralGiven = borrowerSeat.getAmountAllocated(
       'Collateral',
-      borrowerSeat.getProposal().give.Collateral.brand,
+      /** @type {Brand<'nat'>} */ (
+        borrowerSeat.getProposal().give.Collateral.brand
+      ),
     );
     const loanWanted = borrowerSeat.getProposal().want.Loan;
     const loanBrand = zcf.getTerms().brands.Loan;
diff --git a/packages/zoe/src/contracts/priceAggregator.js b/packages/zoe/src/contracts/priceAggregator.js
index 97bcff66f04..a1be89dc22c 100644
--- a/packages/zoe/src/contracts/priceAggregator.js
+++ b/packages/zoe/src/contracts/priceAggregator.js
@@ -60,7 +60,7 @@ const priceDescriptionFromQuote = quote => quote.quoteAmount.value[0];
  * }>} zcf
  * @param {{
  * marshaller: Marshaller,
- * quoteMint?: ERef<Mint<'set'>>,
+ * quoteMint?: ERef<Mint<'set', PriceDescription>>,
  * storageNode: ERef<StorageNode>,
  * }} privateArgs
  */
@@ -78,12 +78,11 @@ const start = async (zcf, privateArgs) => {
   const { marshaller, storageNode } = privateArgs;
   assertAllDefined({ marshaller, storageNode });
 
+  /** @type {ERef<Mint<'set', PriceDescription>>} */
   const quoteMint =
     privateArgs.quoteMint ||
     // makeIssuerKit fails upgrade, this contract is for demo only
     makeIssuerKit('quote', AssetKind.SET).mint;
-  /** @type {IssuerRecord<'set'>} */
-  // xxx saveIssuer not generic
   const quoteIssuerRecord = await zcf.saveIssuer(
     E(quoteMint).getIssuer(),
     'Quote',
@@ -101,8 +100,6 @@ const start = async (zcf, privateArgs) => {
    * @param {PriceQuoteValue} quote
    */
   const authenticateQuote = async quote => {
-    /** @type {Amount<'set'>} */
-    // xxx type should be inferred from brand and value
     const quoteAmount = AmountMath.make(quoteKit.brand, harden(quote));
     const quotePayment = await E(quoteKit.mint).mintPayment(quoteAmount);
     return harden({ quoteAmount, quotePayment });
diff --git a/packages/zoe/src/internal-types.js b/packages/zoe/src/internal-types.js
index 7de031ab808..b84970e0ffb 100644
--- a/packages/zoe/src/internal-types.js
+++ b/packages/zoe/src/internal-types.js
@@ -53,13 +53,16 @@
  */
 
 /**
- * @typedef {object} ZoeSeatAdmin
+ * @typedef ZoeSeatAdminMethods
  * @property {(allocation: Allocation) => void} replaceAllocation
  * @property {ZoeSeatAdminExit} exit
  * @property {import('@agoric/swingset-vat').ShutdownWithFailure} fail called with the reason
  * for calling fail on this seat, where reason is normally an instanceof Error.
  * @property {() => Subscriber<AmountKeywordRecord>} getExitSubscriber
  */
+/**
+ * @typedef {import('@endo/marshal').RemotableObject & ZoeSeatAdminMethods} ZoeSeatAdmin
+ */
 
 /**
  * @callback {(brand: Brand) => AssetKind} GetAssetKind
@@ -67,7 +70,7 @@
 
 /**
  * @typedef {object} HandleOfferResult
- * @property {Promise<unknown>} offerResultPromise
+ * @property {Promise<import('@endo/marshal').Passable>} offerResultPromise
  * @property {ExitObj} exitObj
  */
 
@@ -122,9 +125,9 @@
 /**
  * @typedef {object} ZoeInstanceAdmin
  * @property {ZoeInstanceAdminMakeInvitation} makeInvitation
- * @property {(issuerP: ERef<Issuer>,
+ * @property {<I extends Issuer>(issuerP: ERef<I>,
  *             keyword: Keyword
- *            ) => Promise<IssuerRecord>} saveIssuer
+ *            ) => Promise<I extends Issuer<infer K, infer M> ? IssuerRecord<K, M> : never>} saveIssuer
  * @property {MakeZoeMint} makeZoeMint
  * @property {RegisterFeeMint} registerFeeMint
  * @property {MakeNoEscrowSeat} makeNoEscrowSeat
diff --git a/packages/zoe/src/types-ambient.js b/packages/zoe/src/types-ambient.js
index 0e4b4207ad4..dd640c50611 100644
--- a/packages/zoe/src/types-ambient.js
+++ b/packages/zoe/src/types-ambient.js
@@ -4,10 +4,7 @@
 
 /**
  * @template {string} H - the name of the handle
- * @typedef {H & import("@endo/marshal").Remotable} Handle A type constructor for an opaque type
- * identified by the H string. This uses an intersection type
- * ('MyHandle' & {}) to tag the handle's type even though the actual
- * value is just an empty object.
+ * @typedef {import("@endo/marshal").RemotableObject<H>} Handle Alias for RemotableObject
  */
 
 /**
@@ -35,9 +32,10 @@
 
 /**
  * @template {AssetKind} [K=AssetKind]
+ * @template {import("@endo/patterns").Key} [M=import("@endo/patterns").Key] member kind, for Amounts that have member values
  * @typedef {object} IssuerRecord
  * @property {Brand<K>} brand
- * @property {Issuer<K>} issuer
+ * @property {Issuer<K, M>} issuer
  * @property {K} assetKind
  * @property {DisplayInfo<K>} [displayInfo]
  *
diff --git a/packages/zoe/src/zoeService/escrowStorage.js b/packages/zoe/src/zoeService/escrowStorage.js
index 357ca9b880f..6c20944d02b 100644
--- a/packages/zoe/src/zoeService/escrowStorage.js
+++ b/packages/zoe/src/zoeService/escrowStorage.js
@@ -16,7 +16,7 @@ import { cleanKeywords } from '../cleanProposal.js';
  * @param {import('@agoric/vat-data').Baggage} baggage
  */
 export const provideEscrowStorage = baggage => {
-  /** @type {WeakMapStore<Brand, ERef<Purse>>} */
+  /** @type {WeakMapStore<Brand, Purse>} */
   const brandToPurse = provideDurableWeakMapStore(baggage, 'brandToPurse');
 
   /** @type {CreatePurse} */
diff --git a/packages/zoe/src/zoeService/makeInvitation.js b/packages/zoe/src/zoeService/makeInvitation.js
index 320de457143..5a755ed0d7a 100644
--- a/packages/zoe/src/zoeService/makeInvitation.js
+++ b/packages/zoe/src/zoeService/makeInvitation.js
@@ -28,6 +28,9 @@ export const prepareInvitationKit = (baggage, shutdownZoeVat = undefined) => {
     // Upgrade this legacy state by simply deleting it.
     invitationKitBaggage.delete(ZOE_INVITATION_KIT);
   }
+
+  /** @type {IssuerKit<'set', InvitationDetails>} */
+  // @ts-expect-error cast
   const invitationKit = prepareIssuerKit(
     invitationKitBaggage,
     'Zoe Invitation',
diff --git a/packages/zoe/src/zoeService/originalZoeSeat.js b/packages/zoe/src/zoeService/originalZoeSeat.js
index 97e4660851d..68a2ed2d92f 100644
--- a/packages/zoe/src/zoeService/originalZoeSeat.js
+++ b/packages/zoe/src/zoeService/originalZoeSeat.js
@@ -135,7 +135,7 @@ export const declareOldZoeSeatAdminKind = (baggage, makeDurablePublishKit) => {
         currentAllocation: initialAllocation,
         proposal,
         exitObj,
-        offerResult: undefined,
+        offerResult: /** @type {any} */ (undefined),
         offerResultStored: offerResultIsUndefined,
         instanceAdminHelper,
         withdrawFacet,
@@ -217,7 +217,7 @@ export const declareOldZoeSeatAdminKind = (baggage, makeDurablePublishKit) => {
           }
 
           const pKit = ephemeralOfferResultStore.get(facets.userSeat);
-          E.when(
+          void E.when(
             offerResultPromise,
             offerResult => {
               // Resolve the ephemeral promise for offerResult
@@ -240,7 +240,8 @@ export const declareOldZoeSeatAdminKind = (baggage, makeDurablePublishKit) => {
                     ephemeralOfferResultStore.delete(facets.userSeat);
                   } catch (err) {
                     console.warn(
-                      `non-durable offer result will be lost upon zoe vat termination: ${offerResult}`,
+                      'non-durable offer result will be lost upon zoe vat termination:',
+                      offerResult,
                     );
                   }
                 },
diff --git a/packages/zoe/src/zoeService/startInstance.js b/packages/zoe/src/zoeService/startInstance.js
index ea70986549d..d18869da130 100644
--- a/packages/zoe/src/zoeService/startInstance.js
+++ b/packages/zoe/src/zoeService/startInstance.js
@@ -274,9 +274,13 @@ export const makeStartInstance = (
     },
   );
 
+  /**
+   * @type {import('./utils.js').StartInstance}
+   */
   const startInstance = async (
     installationP,
     uncleanIssuerKeywordRecord = harden({}),
+    // @ts-expect-error FIXME may not match the expected terms of SF
     customTerms = harden({}),
     privateArgs = undefined,
     instanceLabel = '',
@@ -330,6 +334,7 @@ export const makeStartInstance = (
     void watchForAdminNodeDone(adminNode, instanceAdmin);
 
     /** @type {ZoeInstanceAdmin} */
+    // @ts-expect-error XXX saveIssuer
     const zoeInstanceAdminForZcf = makeZoeInstanceAdmin(
       zoeInstanceStorageManager,
       instanceAdmin,
@@ -355,6 +360,7 @@ export const makeStartInstance = (
 
     // creatorInvitation can be undefined, but if it is defined,
     // let's make sure it is an invitation.
+    // @ts-expect-error cast
     return E.when(
       Promise.all([
         creatorInvitationP,
@@ -383,6 +389,5 @@ export const makeStartInstance = (
       },
     );
   };
-  // @ts-expect-error cast
   return harden(startInstance);
 };
diff --git a/packages/zoe/src/zoeService/types-ambient.js b/packages/zoe/src/zoeService/types-ambient.js
index 17d9f7a31e1..24322cf7099 100644
--- a/packages/zoe/src/zoeService/types-ambient.js
+++ b/packages/zoe/src/zoeService/types-ambient.js
@@ -49,7 +49,7 @@
 
 /**
  * @callback GetInvitationIssuer
- * @returns {Promise<Issuer<'set'>>}
+ * @returns {Promise<Issuer<'set', InvitationDetails>>}
  */
 
 /**
@@ -232,7 +232,7 @@
  */
 
 /**
- * @typedef {Record<Keyword, Amount<any>>} AmountKeywordRecord
+ * @typedef {Record<Keyword, import('@agoric/ertp/exported.js').AnyAmount>} AmountKeywordRecord
  *
  * The keys are keywords, and the values are amounts. For example:
  * { Asset: AmountMath.make(assetBrand, 5n), Price:
diff --git a/packages/zoe/src/zoeService/utils.d.ts b/packages/zoe/src/zoeService/utils.d.ts
index 6a31f5973a0..f94b6762d98 100644
--- a/packages/zoe/src/zoeService/utils.d.ts
+++ b/packages/zoe/src/zoeService/utils.d.ts
@@ -1,8 +1,9 @@
-import type { Callable } from '@agoric/internal/src/utils.js';
+import type { Issuer } from '@agoric/ertp/exported.js';
 import type { Tagged } from '@agoric/internal/src/tagged.js';
-import type { VatUpgradeResults } from '@agoric/swingset-vat';
+import type { Callable } from '@agoric/internal/src/utils.js';
 import type { Baggage } from '@agoric/swingset-liveslots';
-import type { Issuer } from '@agoric/ertp/exported.js';
+import type { VatUpgradeResults } from '@agoric/swingset-vat';
+import type { RemotableObject } from '@endo/marshal';
 
 // XXX https://github.com/Agoric/agoric-sdk/issues/4565
 type SourceBundle = Record<string, any>;
@@ -14,19 +15,18 @@ type ContractFacet<T extends {} = {}> = {
 /**
  * Installation of a contract, typed by its start function.
  */
-export type Installation<SF extends ContractStartFunction | unknown> = Tagged<
-  {
-    getBundle: () => SourceBundle;
-    getBundleLabel: () => string;
-  },
-  'StartFunction',
-  SF
->;
-export type Instance<SF extends ContractStartFunction | unknown> = Tagged<
-  Handle<'Instance'>,
-  'StartFunction',
-  SF
->;
+export type Installation<SF extends ContractStartFunction | unknown> =
+  RemotableObject &
+    Tagged<
+      {
+        getBundle: () => SourceBundle;
+        getBundleLabel: () => string;
+      },
+      'StartFunction',
+      SF
+    >;
+export type Instance<SF extends ContractStartFunction | unknown> =
+  RemotableObject & Tagged<Handle<'Instance'>, 'StartFunction', SF>;
 
 export type InstallationStart<I> =
   I extends Installation<infer SF> ? SF : never;
@@ -37,7 +37,7 @@ export type ContractStartFunction = (
   baggage?: Baggage,
 ) => ERef<{ creatorFacet?: {}; publicFacet?: {} }>;
 
-export type AdminFacet<SF extends ContractStartFunction> = {
+export type AdminFacet<SF extends ContractStartFunction> = RemotableObject & {
   // Completion, which is currently any
   getVatShutdownPromise: () => Promise<any>;
   upgradeContract: Parameters<SF>[1] extends undefined
diff --git a/packages/zoe/src/zoeService/zoeSeat.js b/packages/zoe/src/zoeService/zoeSeat.js
index 688dcbb6a52..31abb4aa8c8 100644
--- a/packages/zoe/src/zoeService/zoeSeat.js
+++ b/packages/zoe/src/zoeService/zoeSeat.js
@@ -109,7 +109,7 @@ export const makeZoeSeatAdminFactory = baggage => {
       return {
         currentAllocation: initialAllocation,
         proposal,
-        offerResult: undefined,
+        offerResult: /** @type {any} */ (undefined),
         offerResultStored: offerResultIsUndefined,
         instanceAdminHelper,
         withdrawFacet,
@@ -312,7 +312,8 @@ export const makeZoeSeatAdminFactory = baggage => {
                     ephemeralOfferResultStore.delete(facets.zoeSeatAdmin);
                   } catch (err) {
                     console.warn(
-                      `non-durable offer result will be lost upon zoe vat termination: ${offerResult}`,
+                      'non-durable offer result will be lost upon zoe vat termination:',
+                      offerResult,
                     );
                   }
                 },
diff --git a/packages/zoe/src/zoeService/zoeStorageManager.js b/packages/zoe/src/zoeService/zoeStorageManager.js
index e1f49abcea4..ae763e42adc 100644
--- a/packages/zoe/src/zoeService/zoeStorageManager.js
+++ b/packages/zoe/src/zoeService/zoeStorageManager.js
@@ -275,8 +275,9 @@ export const makeZoeStorageManager = (
             ownKeys(customDetails).length >= 1
               ? harden({ customDetails })
               : harden({});
+          /** @type {InvitationAmount} */
           const invitationAmount = AmountMath.make(
-            invitationKit.brand,
+            /** @type {Brand<'set'>} */ (invitationKit.brand),
             harden([
               {
                 ...extraProperties,
@@ -401,6 +402,7 @@ export const makeZoeStorageManager = (
       contractBundleCap,
       contractLabel,
     );
+    // @ts-expect-error checked cast
     return makeInstanceStorageManager(instanceRecord, adminNode, root)
       .instanceStorageManager;
   };
diff --git a/packages/zoe/test/types.test-d.ts b/packages/zoe/test/types.test-d.ts
index e747384b9d8..f6f46eee091 100644
--- a/packages/zoe/test/types.test-d.ts
+++ b/packages/zoe/test/types.test-d.ts
@@ -5,8 +5,9 @@
  * https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html
  */
 import { E } from '@endo/eventual-send';
-import { expectNotType, expectType } from 'tsd';
+import { expectType } from 'tsd';
 
+import type { Key } from '@endo/patterns';
 // 'prepare' is deprecated but still supported
 import type { prepare as scaledPriceAuthorityStart } from '../src/contracts/scaledPriceAuthority.js';
 
@@ -79,3 +80,8 @@ import type { prepare as scaledPriceAuthorityStart } from '../src/contracts/scal
   result.notInResult;
   expectType<bigint>(result);
 }
+
+{
+  const zcfSeat: ZCFSeat = null as any;
+  expectType<Key>(zcfSeat);
+}
diff --git a/packages/zoe/test/unitTests/contracts/test-oracle.js b/packages/zoe/test/unitTests/contracts/test-oracle.js
index 10e02e4fd3b..d235b15166d 100644
--- a/packages/zoe/test/unitTests/contracts/test-oracle.js
+++ b/packages/zoe/test/unitTests/contracts/test-oracle.js
@@ -124,26 +124,15 @@ test('single oracle', /** @param {ExecutionContext} t */ async t => {
   t.truthy(await E(invitationIssuer).isLive(invitation3));
   t.truthy(await E(invitationIssuer).isLive(invitation4));
 
-  t.deepEqual(
-    (await E(invitationIssuer).getAmountOf(invitation1)).value[0].customDetails
-      .query,
-    query1,
-  );
-  t.deepEqual(
-    (await E(invitationIssuer).getAmountOf(invitation2)).value[0].customDetails
-      .query,
-    query2,
-  );
-  t.deepEqual(
-    (await E(invitationIssuer).getAmountOf(invitation3)).value[0].customDetails
-      .query,
-    query3,
-  );
-  t.deepEqual(
-    (await E(invitationIssuer).getAmountOf(invitation4)).value[0].customDetails
-      .query,
-    query4,
-  );
+  const getCustomDetailsQuery = async inv => {
+    const amt = await E(invitationIssuer).getAmountOf(inv);
+    return amt.value[0].customDetails?.query;
+  };
+
+  t.deepEqual(await getCustomDetailsQuery(invitation1), query1);
+  t.deepEqual(await getCustomDetailsQuery(invitation2), query2);
+  t.deepEqual(await getCustomDetailsQuery(invitation3), query3);
+  t.deepEqual(await getCustomDetailsQuery(invitation4), query4);
 
   const offer = E(zoe).offer(invitation1);
 
diff --git a/packages/zoe/test/unitTests/contracts/test-priceAggregator.js b/packages/zoe/test/unitTests/contracts/test-priceAggregator.js
index d1ddc92455b..1dd656d8230 100644
--- a/packages/zoe/test/unitTests/contracts/test-priceAggregator.js
+++ b/packages/zoe/test/unitTests/contracts/test-priceAggregator.js
@@ -53,7 +53,7 @@ import {
  * }>} zcf
  * @param {{
  * marshaller: Marshaller,
- * quoteMint?: ERef<Mint<'set'>>,
+ * quoteMint?: ERef<Mint<'set', PriceDescription>>,
  * storageNode: StorageNode,
  * }} privateArgs
  */
@@ -81,7 +81,7 @@ const makePublicationChecker = async (t, aggregatorPublicFacet, timerBrand) => {
   )[Symbol.asyncIterator]();
 
   return {
-    /** @param {{timestamp: bigint, amountOut: any}} spec */
+    /** @param {{timestamp: import('@agoric/time').Timestamp, amountOut: any}} spec */
     async nextMatches({ timestamp, amountOut }) {
       const expectedTimestamp = TimeMath.coerceTimestampRecord(
         timestamp,
@@ -202,8 +202,10 @@ test('median aggregator', async t => {
   } = await E(zoe).getTerms(aggregator.instance);
   const timerBrand = oracleTimer.getTimerBrand();
   const toTS = ts => TimeMath.coerceTimestampRecord(ts, timerBrand);
-  /** @type {Issuer<'set'>} */
-  const quoteIssuer = rawQuoteIssuer;
+
+  const quoteIssuer = /** @type {Issuer<'set', PriceDescription>} */ (
+    rawQuoteIssuer
+  );
 
   const price1000 = await makeFakePriceOracle(1000n);
   const price1300 = await makeFakePriceOracle(1300n);
@@ -363,8 +365,10 @@ test('median aggregator - push only', async t => {
   } = await E(zoe).getTerms(aggregator.instance);
   const toTS = ts =>
     TimeMath.coerceTimestampRecord(ts, oracleTimer.getTimerBrand());
-  /** @type {Issuer<'set'>} */
-  const quoteIssuer = rawQuoteIssuer;
+
+  const quoteIssuer = /** @type {Issuer<'set', PriceDescription>} */ (
+    rawQuoteIssuer
+  );
 
   const pricePush = await makeFakePriceOracle();
   const pa = E(aggregator.publicFacet).getPriceAuthority();
@@ -599,8 +603,9 @@ test('quoteAtTime', async t => {
   } = await E(zoe).getTerms(aggregator.instance);
   const toTS = ts =>
     TimeMath.coerceTimestampRecord(ts, oracleTimer.getTimerBrand());
-  /** @type {Issuer<'set'>} */
-  const quoteIssuer = rawQuoteIssuer;
+  const quoteIssuer = /** @type {Issuer<'set', PriceDescription>} */ (
+    rawQuoteIssuer
+  );
 
   const price1000 = await makeFakePriceOracle(1000n);
   const price1300 = await makeFakePriceOracle(1300n);
@@ -713,8 +718,9 @@ test('quoteWhen', async t => {
   } = await E(zoe).getTerms(aggregator.instance);
   const toTS = ts =>
     TimeMath.coerceTimestampRecord(ts, oracleTimer.getTimerBrand());
-  /** @type {Issuer<'set'>} */
-  const quoteIssuer = rawQuoteIssuer;
+  const quoteIssuer = /** @type {Issuer<'set', PriceDescription>} */ (
+    rawQuoteIssuer
+  );
 
   const price1000 = await makeFakePriceOracle(1000n);
   const price1300 = await makeFakePriceOracle(1300n);
@@ -823,8 +829,9 @@ test('mutableQuoteWhen no replacement', async t => {
     brandOut,
   } = await E(zoe).getTerms(aggregator.instance);
   const timerBrand = await E(oracleTimer).getTimerBrand();
-  /** @type {Issuer<'set'>} */
-  const quoteIssuer = rawQuoteIssuer;
+  const quoteIssuer = /** @type {Issuer<'set', PriceDescription>} */ (
+    rawQuoteIssuer
+  );
 
   const price1000 = await makeFakePriceOracle(1000n);
   const price1300 = await makeFakePriceOracle(1300n);
@@ -941,8 +948,9 @@ test('mutableQuoteWhen with update', async t => {
   } = await E(zoe).getTerms(aggregator.instance);
   const toTS = ts =>
     TimeMath.coerceTimestampRecord(ts, oracleTimer.getTimerBrand());
-  /** @type {Issuer<'set'>} */
-  const quoteIssuer = rawQuoteIssuer;
+  const quoteIssuer = /** @type {Issuer<'set', PriceDescription>} */ (
+    rawQuoteIssuer
+  );
 
   const price1200 = await makeFakePriceOracle(1200n);
   const pa = E(aggregator.publicFacet).getPriceAuthority();
diff --git a/packages/zoe/test/unitTests/contracts/test-sellTickets.js b/packages/zoe/test/unitTests/contracts/test-sellTickets.js
index 32fe86deb9b..8ddb9d84894 100644
--- a/packages/zoe/test/unitTests/contracts/test-sellTickets.js
+++ b/packages/zoe/test/unitTests/contracts/test-sellTickets.js
@@ -146,6 +146,7 @@ test(`mint and sell opera tickets`, async t => {
     brand: moolaBrand,
   } = makeIssuerKit('moola');
 
+  /** @param {bigint} value */
   const moola = value => AmountMath.make(moolaBrand, value);
 
   const { admin: fakeVatAdmin, vatAdminState } = makeFakeVatAdmin();
@@ -442,7 +443,7 @@ test(`mint and sell opera tickets`, async t => {
     const bobPurse = await E(moolaIssuer).makeEmptyPurse();
     await E(bobPurse).deposit(moola100Payment);
 
-    /** @type {Amount} */
+    /** @type {Amount<'set', {number: number}>} */
     const availableTickets = await E(
       ticketSalesPublicFacet,
     ).getAvailableItems();
diff --git a/packages/zoe/test/unitTests/setupBasicMints.js b/packages/zoe/test/unitTests/setupBasicMints.js
index d00d3fe42e7..0ca43e22b0e 100644
--- a/packages/zoe/test/unitTests/setupBasicMints.js
+++ b/packages/zoe/test/unitTests/setupBasicMints.js
@@ -22,7 +22,7 @@ export const setup = () => {
   const { admin: fakeVatAdmin, vatAdminState } = makeFakeVatAdmin();
   const zoe = makeZoeForTest(fakeVatAdmin);
 
-  /** @type {<K extends AssetKind>(brand: Brand<K>) => (value: any) => Amount<K>} */
+  /** @type {(brand: Brand<'nat'>) => (value: bigint) => Amount<'nat'>} */
   const makeSimpleMake = brand => value => AmountMath.make(brand, value);
 
   const result = {
diff --git a/packages/zoe/tools/fakePriceAuthority.js b/packages/zoe/tools/fakePriceAuthority.js
index 7c93d869ce8..3abdbca3ccb 100644
--- a/packages/zoe/tools/fakePriceAuthority.js
+++ b/packages/zoe/tools/fakePriceAuthority.js
@@ -28,7 +28,7 @@ const timestampLTE = (a, b) => TimeMath.compareAbs(a, b) <= 0;
  * @property {Brand<'nat'>} actualBrandOut
  * @property {Array<number>} [priceList]
  * @property {Array<[number, number]>} [tradeList]
- * @property {ERef<import('@agoric/time').TimerService>} timer
+ * @property {import('@agoric/time').TimerService} timer
  * @property {import('@agoric/time').RelativeTime} [quoteInterval]
  * @property {ERef<Mint<'set'>>} [quoteMint]
  * @property {Amount<'nat'>} [unitAmountIn]
@@ -117,16 +117,19 @@ export async function makeFakePriceAuthority(options) {
       natSafeMath.multiply(amountIn.value, tradeValueOut),
       tradeValueIn,
     );
+    /** @type {Amount<'set', PriceDescription>} */
     const quoteAmount = AmountMath.make(
       quoteBrand,
-      harden([
-        {
-          amountIn,
-          amountOut: AmountMath.make(actualBrandOut, valueOut),
-          timer,
-          timestamp: quoteTime,
-        },
-      ]),
+      /** @type {[PriceDescription]} */ (
+        harden([
+          {
+            amountIn,
+            amountOut: AmountMath.make(actualBrandOut, valueOut),
+            timer,
+            timestamp: quoteTime,
+          },
+        ])
+      ),
     );
     const quote = harden({
       quotePayment: E(quoteMint).mintPayment(quoteAmount),
diff --git a/packages/zoe/tools/manualTimer.js b/packages/zoe/tools/manualTimer.js
index 44c9f3a639b..8573bfe7442 100644
--- a/packages/zoe/tools/manualTimer.js
+++ b/packages/zoe/tools/manualTimer.js
@@ -3,7 +3,11 @@ import { bindAllMethods } from '@agoric/internal';
 import { buildManualTimer as build } from '@agoric/swingset-vat/tools/manual-timer.js';
 import { TimeMath } from '@agoric/time';
 
-/** @import {TimerService} from '@agoric/time' */
+/**
+ * @import {TimerServiceI} from '@agoric/time';
+ * @import {RemotableObject} from '@endo/pass-style';
+ * @import {RemotableBrand} from '@endo/eventual-send';
+ */
 
 const { Fail } = assert;
 
@@ -28,9 +32,7 @@ const nolog = (..._args) => {};
  * @property {(nTimes: number, msg?: string) => Promise<void>} tickN
  */
 
-/**
- * @typedef {TimerService & ManualTimerAdmin} ManualTimer
- */
+/** @typedef {TimerServiceI & RemotableObject<'TimerService'> & RemotableBrand<ManualTimerAdmin, TimerServiceI & ManualTimerAdmin> & ManualTimerAdmin} ManualTimer */
 
 /**
  * A fake TimerService, for unit tests that do not use a real
diff --git a/packages/zoe/tools/types.js b/packages/zoe/tools/types.js
index 13ee37f5de5..527b2d79676 100644
--- a/packages/zoe/tools/types.js
+++ b/packages/zoe/tools/types.js
@@ -3,9 +3,9 @@ export {};
 
 /**
  * @typedef {object} PriceQuote
- * @property {Amount<'set'>} quoteAmount
+ * @property {Amount<'set', PriceDescription>} quoteAmount
  * Amount whose value is a PriceQuoteValue
- * @property {ERef<Payment<'set'>>} quotePayment
+ * @property {ERef<Payment<'set', PriceDescription>>} quotePayment
  * The `quoteAmount` wrapped as a payment
  */
 
@@ -22,7 +22,7 @@ export {};
  * The amount supplied to a trade
  * @property {Amount<'nat'>} amountOut
  * The quoted result of trading `amountIn`
- * @property {import('@agoric/time').TimerService} timer
+ * @property {import('@endo/pass-style').RemotableObject & import('@agoric/time').TimerService} timer
  * The service that gave the `timestamp`
  * @property {import('@agoric/time').TimestampRecord} timestamp
  * A timestamp according to `timer` for the quote
@@ -64,7 +64,7 @@ export {};
  * An object that mints PriceQuotes and handles
  * triggers and notifiers for changes in the price
  *
- * @property {(brandIn: Brand, brandOut: Brand) => ERef<Issuer<'set'>>} getQuoteIssuer
+ * @property {(brandIn: Brand, brandOut: Brand) => ERef<Issuer<'set', PriceDescription>>} getQuoteIssuer
  * Get the ERTP issuer of PriceQuotes for a given brandIn/brandOut pair
  *
  * @property {(brandIn: Brand,
diff --git a/packages/zone/src/durable.js b/packages/zone/src/durable.js
index 75f632e9e00..34bcb69cd51 100644
--- a/packages/zone/src/durable.js
+++ b/packages/zone/src/durable.js
@@ -12,6 +12,7 @@ import {
   provideDurableSetStore,
   provideDurableWeakMapStore,
   provideDurableWeakSetStore,
+  watchPromise,
 } from '@agoric/vat-data';
 
 import { agoricVatDataKeys as keys, makeOnceKit } from '@agoric/base-zone';
@@ -95,6 +96,7 @@ export const makeDurableZone = (baggage, baseLabel = 'durableZone') => {
 
   /** @type {import('.').Zone['subZone']} */
   const subZone = (label, options = {}) => {
+    /** @type {import('@agoric/swingset-liveslots').Baggage} */
     const subBaggage = subZoneStore(label, options);
     return makeDurableZone(subBaggage, `${baseLabel}.${label}`);
   };
@@ -106,6 +108,7 @@ export const makeDurableZone = (baggage, baseLabel = 'durableZone') => {
     subZone,
 
     makeOnce,
+    watchPromise,
     detached: attachedStores.detached,
     isStorable: attachedStores.isStorable,
 
diff --git a/packages/zone/src/virtual.js b/packages/zone/src/virtual.js
index 89a0a78a37c..5cba65cc268 100644
--- a/packages/zone/src/virtual.js
+++ b/packages/zone/src/virtual.js
@@ -11,7 +11,11 @@ import {
   makeScalarBigWeakSetStore,
 } from '@agoric/vat-data';
 
-import { agoricVatDataKeys as keys, makeOnceKit } from '@agoric/base-zone';
+import {
+  agoricVatDataKeys as keys,
+  makeOnceKit,
+  watchPromise,
+} from '@agoric/base-zone';
 
 const emptyRecord = harden({});
 const initEmpty = harden(() => emptyRecord);
@@ -79,6 +83,7 @@ export const makeVirtualZone = (baseLabel = 'virtualZone') => {
     subZone: wrapProvider(makeSubZone),
 
     makeOnce,
+    watchPromise,
     detached: detachedVirtualStores.detached,
     isStorable: detachedVirtualStores.isStorable,
 
diff --git a/patches/@endo+exo+1.4.0.patch b/patches/@endo+exo+1.4.0.patch
deleted file mode 100644
index aad2781fa3b..00000000000
--- a/patches/@endo+exo+1.4.0.patch
+++ /dev/null
@@ -1,10 +0,0 @@
-diff --git a/node_modules/@endo/exo/index.d.ts b/node_modules/@endo/exo/index.d.ts
-index 3bc696d..55df34e 100644
---- a/node_modules/@endo/exo/index.d.ts
-+++ b/node_modules/@endo/exo/index.d.ts
-@@ -1,3 +1,4 @@
- export * from "./src/exo-makers.js";
- export { GET_INTERFACE_GUARD } from "./src/get-interface.js";
-+export * from "./src/types.js";
- //# sourceMappingURL=index.d.ts.map
-\ No newline at end of file
diff --git a/scripts/replace-packages.sh b/scripts/replace-packages.sh
index dc934a93cec..7d6817a649f 100755
--- a/scripts/replace-packages.sh
+++ b/scripts/replace-packages.sh
@@ -13,7 +13,9 @@ DSTDIR=${2-$PWD/node_modules}
 # Install and build the source directory.
 pushd "$SRCDIR"
 yarn install
-yarn build
+npm run build
+# Endo requires this
+npx lerna run build:types || true
 npm query .workspace | jq -r '.[].location' | while read -r dir; do
   # Skip private packages.
   test "$(jq .private < "$dir/package.json")" != true || continue
@@ -23,7 +25,7 @@ npm query .workspace | jq -r '.[].location' | while read -r dir; do
   name=$(jq -r .name < package.json)
   stem=$(echo "$name" | sed -e 's!^@!!; s!/!-!g;')
   rm -f "${stem}"-*.tgz
-  yarn pack
+  npm pack
   tar -xvf "${stem}"-*.tgz
 
   # Replace the destination package.
diff --git a/yarn.lock b/yarn.lock
index a06fdbccfad..003c84e0dc5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -8732,10 +8732,10 @@ minimatch@5.1.0:
   dependencies:
     brace-expansion "^2.0.1"
 
-"minimatch@6 || 7 || 8 || 9", minimatch@^9.0.1, minimatch@^9.0.3:
-  version "9.0.3"
-  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-9.0.3.tgz#a6e00c3de44c3a542bfaae70abfc22420a6da825"
-  integrity sha512-RHiac9mvaRw0x3AYRgDC1CxAP7HTcNrrECeA8YYJeWnpo+2Q5CegtZjaotWTWxDG3UeGA1coE05iH1mPjT/2mg==
+"minimatch@6 || 7 || 8 || 9", minimatch@^9.0.1, minimatch@^9.0.3, minimatch@^9.0.4:
+  version "9.0.4"
+  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-9.0.4.tgz#8e49c731d1749cbec05050ee5145147b32496a51"
+  integrity sha512-KqWh+VchfxcMNRAJjj2tnsSJdNbHsVgnkBhTNrW7AjVo6OvLtxw8zfT9oLw1JSohlFzJ8jCoTgaoXvJ+kHt6fw==
   dependencies:
     brace-expansion "^2.0.1"
 
@@ -8753,13 +8753,6 @@ minimatch@^5.0.1:
   dependencies:
     brace-expansion "^2.0.1"
 
-minimatch@^9.0.4:
-  version "9.0.4"
-  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-9.0.4.tgz#8e49c731d1749cbec05050ee5145147b32496a51"
-  integrity sha512-KqWh+VchfxcMNRAJjj2tnsSJdNbHsVgnkBhTNrW7AjVo6OvLtxw8zfT9oLw1JSohlFzJ8jCoTgaoXvJ+kHt6fw==
-  dependencies:
-    brace-expansion "^2.0.1"
-
 minimist-options@4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/minimist-options/-/minimist-options-4.1.0.tgz#c0655713c53a8a2ebd77ffa247d342c40f010619"
@@ -11366,12 +11359,7 @@ triple-beam@^1.3.0:
   resolved "https://registry.yarnpkg.com/triple-beam/-/triple-beam-1.4.1.tgz#6fde70271dc6e5d73ca0c3b24e2d92afb7441984"
   integrity sha512-aZbgViZrg1QNcG+LULa7nhZpJTZSLm/mXnHXnbAbjmN5aSa0y7V+wvv6+4WaBtpISJzThKy+PIPxc1Nq1EJ9mg==
 
-ts-api-utils@^1.0.1:
-  version "1.2.1"
-  resolved "https://registry.yarnpkg.com/ts-api-utils/-/ts-api-utils-1.2.1.tgz#f716c7e027494629485b21c0df6180f4d08f5e8b"
-  integrity sha512-RIYA36cJn2WiH9Hy77hdF9r7oEwxAtB/TS9/S4Qd90Ap4z5FSiin5zEiTL44OII1Y3IIlEvxwxFUVgrHSZ/UpA==
-
-ts-api-utils@^1.3.0:
+ts-api-utils@^1.0.1, ts-api-utils@^1.3.0:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/ts-api-utils/-/ts-api-utils-1.3.0.tgz#4b490e27129f1e8e686b45cc4ab63714dc60eea1"
   integrity sha512-UQMIo7pb8WRomKR1/+MFVLTroIvDVtMX3K6OUir8ynLyzB8Jeriont2bTAtmNPa1ekAgN7YPDyf6V+ygrdU+eQ==