diff --git a/packages/SwingSet/src/kernel/vatManager/manager-subprocess-xsnap.js b/packages/SwingSet/src/kernel/vatManager/manager-subprocess-xsnap.js
index 58daecb43e4..adfd6fa814b 100644
--- a/packages/SwingSet/src/kernel/vatManager/manager-subprocess-xsnap.js
+++ b/packages/SwingSet/src/kernel/vatManager/manager-subprocess-xsnap.js
@@ -8,6 +8,11 @@ function parentLog(first, ...args) {
   console.error(`--parent: ${first}`, ...args);
 }
 
+const trace = label => x => {
+  parentLog(label, x);
+  return x;
+};
+
 const encoder = new TextEncoder();
 const decoder = new TextDecoder();
 
@@ -25,7 +30,7 @@ const decoder = new TextDecoder();
  * @typedef { ReturnType<typeof import('@agoric/xsnap').xsnap> } XSnap
  * @typedef { ReturnType<typeof import('../state/kernelKeeper').default> } KernelKeeper
  * @typedef { ReturnType<typeof import('./manager-nodeworker').makeNodeWorkerVatManagerFactory> } VatManagerFactory
- * @typedef { [string, ...unknown[]] } Tagged
+ * @typedef { [unknown, ...unknown[]] } Tagged
  */
 export function makeXsSubprocessFactory({
   startXSnap,
@@ -39,7 +44,7 @@ export function makeXsSubprocessFactory({
    * @param { ManagerOptions } managerOptions
    */
   async function createFromBundle(vatID, bundle, managerOptions) {
-    console.log('@@createFromBundle', { vatID, managerOptions: { ...managerOptions, bundle: '<suppressed>' } });
+    parentLog('createFromBundle', { vatID });
     const { vatParameters, virtualObjectCacheSize } = managerOptions;
     assert(!managerOptions.metered, 'not supported yet');
     assert(!managerOptions.enableSetup, 'not supported at all');
@@ -60,9 +65,10 @@ export function makeXsSubprocessFactory({
       transcriptManager,
     );
 
-    /** @type { (vatSyscallObject: Tagged) => Tagged } */
+    //@@??? should this return Tagged?
+    /** @type { (vatSyscallObject: Tagged) => unknown } */
     function handleSyscall(vatSyscallObject) {
-      return doSyscall(vatSyscallObject);
+      return trace('doSyscall')(doSyscall(vatSyscallObject));
     }
 
     /** @type { (vref: unknown, count: number) => void } */
@@ -70,14 +76,13 @@ export function makeXsSubprocessFactory({
       decref(vatID, vref, count);
     }
 
-    /** @type { (item: Tagged) => Tagged } */
+    /** @type { (item: Tagged) => unknown } */
     function handleUpstream([type, ...args]) {
       parentLog(`handleUpstream`, type, args.length);
       switch (type) {
         case 'syscall': {
           parentLog(`syscall`, args);
           const [scTag, ...vatSyscallArgs] = args;
-          assert(typeof scTag === 'string');
           return handleSyscall([scTag, ...vatSyscallArgs]);
         }
         case 'testLog':
@@ -90,47 +95,38 @@ export function makeXsSubprocessFactory({
           return ['OK'];
         }
         default:
-          parentLog(`unrecognized uplink message ${type}`);
-          return ['?'];
+          throw new Error(`unrecognized uplink message ${type}`);
       }
     }
 
     /** @type { (msg: Uint8Array) => Uint8Array } */
     function handleCommand(msg) {
-      console.log('handleCommand', { length: msg.byteLength });
+      parentLog('handleCommand', { length: msg.byteLength });
       const tagged = handleUpstream(JSON.parse(decoder.decode(msg)));
       return encoder.encode(JSON.stringify(tagged));
     }
 
-    console.log('@@do we return from startXSnap?');
     // start the worker and establish a connection
     const { worker, bundles } = startXSnap(`${vatID}`, handleCommand);
-    console.log('@@YES, we return from startXSnap.');
-    await worker.evaluate('1+1'); //@@
-    console.log('and evaluate() finishes @@');
-    console.log('@@bundle keys', Object.keys(bundles.lockdown));
     for await (const [it, superCode] of Object.entries(bundles)) {
+      parentLog('bundle', it);
       assert(
         superCode.moduleFormat === 'getExport',
         details`${it} unexpected: ${superCode.moduleFormat}`,
       );
-      console.log('@@evaluating...', it);
-      const x = await worker.evaluate(
+      await worker.evaluate(
         `(${superCode.source}
             )()`.trim(),
       );
-      console.log('@@evaluated.', it, x);
     }
 
     /** @type { (item: Tagged) => Promise<Tagged> } */
     async function issueTagged(item) {
-      console.log('@@issueTagged', item[0]);
+      parentLog('issueTagged', item[0]);
       const txt = await worker.issueStringCommand(JSON.stringify(item));
       const reply = JSON.parse(txt);
-      console.log('@@reply', Array.isArray(reply), reply[0]);
       assert(Array.isArray(reply));
       const [tag, ...rest] = reply;
-      assert(typeof tag === 'string');
       return [tag, ...rest];
     }
 
@@ -160,7 +156,6 @@ export function makeXsSubprocessFactory({
     /** @type { (item: Tagged) => Promise<Tagged> } */
     async function deliver(delivery) {
       parentLog(`sending delivery`, delivery);
-      // ensure return tag is 'deliverDone'?
       const result = await commandResult(['deliver', ...delivery]);
       parentLog(`deliverDone`, result[0], result.length);
       return result;
@@ -189,7 +184,7 @@ export function makeXsSubprocessFactory({
       shutdown,
     });
 
-    console.log('@@returning manager', Object.keys(manager));
+    parentLog('manager', Object.keys(manager));
     return manager;
   }
 
diff --git a/packages/SwingSet/src/kernel/vatManager/supervisor-subprocess-xsnap.js b/packages/SwingSet/src/kernel/vatManager/supervisor-subprocess-xsnap.js
index 94f396dae7d..1e825db5ae6 100644
--- a/packages/SwingSet/src/kernel/vatManager/supervisor-subprocess-xsnap.js
+++ b/packages/SwingSet/src/kernel/vatManager/supervisor-subprocess-xsnap.js
@@ -2,18 +2,30 @@
 import { assert, details } from '@agoric/assert';
 import { importBundle } from '@agoric/import-bundle';
 import { Remotable, getInterfaceOf, makeMarshal } from '@agoric/marshal';
+// grumble... waitUntilQuiescent is exported and closes over ambient authority
+import { waitUntilQuiescent } from '../../waitUntilQuiescent';
 
 import { makeLiveSlots } from '../liveSlots';
 
 const encoder = new TextEncoder();
 const decoder = new TextDecoder();
 
+// eslint-disable-next-line no-unused-vars
+function workerLog(first, ...args) {
+  // @ts-ignore
+  // eslint-disable-next-line
+  print(`---worker: ${first}`, ...args);
+}
+
+workerLog(`supervisor started`);
+
 /**
  * @typedef { [unknown, ...unknown[]] } Tagged
  */
 const Item = {
   /** @type { (item: Tagged) => ArrayBuffer } */
   encode: tagged => encoder.encode(JSON.stringify(tagged)).buffer,
+
   /** @type { (msg: ArrayBuffer) => Tagged } */
   decode(msg) {
     const txt = decoder.decode(msg);
@@ -44,26 +56,36 @@ function testLog(...args) {
   issueCommand(Item.encode(['testLog', ...args]));
 }
 
-// eslint-disable-next-line no-unused-vars
-function workerLog(first, ...args) {
-  testLog(`---worker: ${first}`, ...args);
+/**
+ * @param { (value: void) => void } f
+ * @param { string } errmsg
+ */
+function runAndWait(f, errmsg) {
+  Promise.resolve()
+    .then(f)
+    .then(undefined, err => workerLog(`doProcess: ${errmsg}:`, err));
+  return waitUntilQuiescent();
 }
 
-workerLog(`supervisor started`);
-
 function makeWorker() {
-  let dispatch;
+  /** @type { Record<string, (...args: unknown[]) => void> | null } */
+  let dispatch = null;
 
+  /** @type { (dr: Tagged, errmsg: string) => Promise<Tagged> } */
   async function doProcess(dispatchRecord, errmsg) {
-    const dispatchOp = dispatchRecord[0];
-    const dispatchArgs = dispatchRecord.slice(1);
+    assert(dispatch);
+    const theDispatch = dispatch;
+    const [dispatchOp, ...dispatchArgs] = dispatchRecord;
+    assert(typeof dispatchOp === 'string');
     workerLog(`runAndWait`);
-    await runAndWait(() => dispatch[dispatchOp](...dispatchArgs), errmsg);
+    await runAndWait(() => theDispatch[dispatchOp](...dispatchArgs), errmsg);
     workerLog(`doProcess done`);
+    /** @type { Tagged } */
     const vatDeliveryResults = harden(['ok']);
     return vatDeliveryResults;
   }
 
+  /** @type { (ts: unknown, msg: any) => Promise<Tagged> } */
   function doMessage(targetSlot, msg) {
     const errmsg = `vat[${targetSlot}].${msg.method} dispatch failed`;
     return doProcess(
@@ -72,6 +94,7 @@ function makeWorker() {
     );
   }
 
+  /** @type { (pv: unknown, msg: any) => Promise<Tagged> } */
   function doNotify(primaryVpid, resolutions) {
     const errmsg = `vat.promise[${primaryVpid}] failed`;
     return doProcess(['notify', primaryVpid, resolutions], errmsg);
@@ -90,12 +113,15 @@ function makeWorker() {
     vatParameters,
     virtualObjectCacheSize,
   ) {
-    /** @type { (item: Tagged) => Tagged } */
+    //@@??? should this return Tagged?
+    /** @type { (item: Tagged) => unknown } */
     function doSyscall(vatSyscallObject) {
-      return Item.decode(
-        // @ts-ignore
-        // eslint-disable-next-line no-undef
-        issueCommand(Item.encode(['syscall', ...vatSyscallObject])),
+      return JSON.parse(
+        decoder.decode(
+          // @ts-ignore
+          // eslint-disable-next-line no-undef
+          issueCommand(Item.encode(['syscall', ...vatSyscallObject])),
+        ),
       );
     }
 
@@ -137,6 +163,7 @@ function makeWorker() {
     workerLog(`got vatNS:`, Object.keys(vatNS).join(','));
     ls.setBuildRootObject(vatNS.buildRootObject);
     dispatch = ls.dispatch;
+    assert(dispatch);
     workerLog(`got dispatch:`, Object.keys(dispatch).join(','));
     return ['dispatchReady'];
   }
@@ -152,11 +179,11 @@ function makeWorker() {
         const [dtype, ...dargs] = args;
         switch (dtype) {
           case 'message': {
-            const res = await doMessage(...dargs);
+            const res = await doMessage(dargs[0], dargs[1]);
             return ['deliverDone', ...res];
           }
           case 'notify': {
-            const res = await doNotify(...dargs);
+            const res = await doNotify(dargs[0], dargs[1]);
             return ['deliverDone', ...res];
           }
           default:
diff --git a/packages/SwingSet/test/workers/test-worker.js b/packages/SwingSet/test/workers/test-worker.js
index d92a613caa0..a1c4a09d3a7 100644
--- a/packages/SwingSet/test/workers/test-worker.js
+++ b/packages/SwingSet/test/workers/test-worker.js
@@ -8,14 +8,12 @@ test('xs vat manager', async t => {
   const c = await buildVatController(config, []);
   t.teardown(c.shutdown);
 
-  console.log('@@ready to run...');
   await c.run();
   t.is(c.kpStatus(c.bootstrapResult), 'fulfilled');
   t.deepEqual(c.dump().log, ['testLog works']);
 });
 
-// @@ SKIP?
-test.skip('nodeWorker vat manager', async t => {
+test('nodeWorker vat manager', async t => {
   const config = await loadBasedir(__dirname);
   config.vats.target.creationOptions = { managerType: 'nodeWorker' };
   const c = await buildVatController(config, []);
@@ -26,8 +24,7 @@ test.skip('nodeWorker vat manager', async t => {
   t.deepEqual(c.dump().log, ['testLog works']);
 });
 
-// @@ SKIP?
-test.skip('node-subprocess vat manager', async t => {
+test('node-subprocess vat manager', async t => {
   const config = await loadBasedir(__dirname);
   config.vats.target.creationOptions = { managerType: 'node-subprocess' };
   const c = await buildVatController(config, []);