diff --git a/.github/workflows/test-all-packages.yml b/.github/workflows/test-all-packages.yml
index 7c99c6973d72..2a02224d4599 100644
--- a/.github/workflows/test-all-packages.yml
+++ b/.github/workflows/test-all-packages.yml
@@ -17,6 +17,8 @@ jobs:
         node-version: ['12.14.1', '12.x', '14.x']
     steps:
     - uses: actions/checkout@v1
+      with:
+        submodules: 'true'
     - uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
@@ -62,6 +64,8 @@ jobs:
         path: .
         key: ${{ runner.os }}-${{ matrix.node-version }}-built-${{ github.sha }}
     - uses: actions/checkout@v1
+      with:
+        submodules: 'true'
       if: steps.built.outputs.cache-hit != 'true'
     - name: yarn install
       run: yarn install
@@ -95,6 +99,8 @@ jobs:
         path: .
         key: ${{ runner.os }}-${{ matrix.node-version }}-built-${{ github.sha }}
     - uses: actions/checkout@v1
+      with:
+        submodules: 'true'
       if: steps.built.outputs.cache-hit != 'true'
     - name: yarn install
       run: yarn install
@@ -252,6 +258,8 @@ jobs:
         path: .
         key: ${{ runner.os }}-${{ matrix.node-version }}-built-${{ github.sha }}
     - uses: actions/checkout@v1
+      with:
+        submodules: 'true'
       if: steps.built.outputs.cache-hit != 'true'
     - name: yarn install
       run: yarn install
@@ -296,18 +304,32 @@ jobs:
         path: .
         key: ${{ runner.os }}-${{ matrix.node-version }}-built-${{ github.sha }}
     - uses: actions/checkout@v1
+      with:
+        submodules: 'true'
       if: steps.built.outputs.cache-hit != 'true'
     - name: yarn install
       run: yarn install
       if: steps.built.outputs.cache-hit != 'true'
+    - name: install XS dependencies
+      working-directory: ./packages/xs-vat-worker
+      run: yarn install:xs-lin
     - name: yarn build
       run: yarn build
       if: steps.built.outputs.cache-hit != 'true'
+    - name: yarn build-xs-worker
+      working-directory: ./packages/xs-vat-worker
+      run: yarn build:xs-lin
     # END-RESTORE-BOILERPLATE
     - name: yarn test (SwingSet)
       run: cd packages/SwingSet && yarn test
       env:
         ESM_DISABLE_CACHE: true
+    # explicitly test the XS worker, for visibility
+    - name: yarn test (SwingSet XS Worker)
+      working-directory: ./packages/SwingSet
+      run: yarn test-xs-worker
+      env:
+        ESM_DISABLE_CACHE: true
 
   test-zoe:
     # BEGIN-TEST-BOILERPLATE
@@ -329,6 +351,8 @@ jobs:
         path: .
         key: ${{ runner.os }}-${{ matrix.node-version }}-built-${{ github.sha }}
     - uses: actions/checkout@v1
+      with:
+        submodules: 'true'
       if: steps.built.outputs.cache-hit != 'true'
     - name: yarn install
       run: yarn install
diff --git a/package.json b/package.json
index c49e4e56a461..46bbf81eeb89 100644
--- a/package.json
+++ b/package.json
@@ -73,7 +73,8 @@
     "test": "yarn workspaces run test",
     "build": "yarn workspaces run build",
     "postinstall": "patch-package",
-    "patch-package": "patch-package"
+    "patch-package": "patch-package",
+    "build-xs-worker": "cd packages/xs-vat-worker && yarn build:xs-lin"
   },
   "dependencies": {
     "patch-package": "^6.2.2"
diff --git a/packages/SwingSet/package.json b/packages/SwingSet/package.json
index ee9460a04d5c..02bc7f625dd7 100644
--- a/packages/SwingSet/package.json
+++ b/packages/SwingSet/package.json
@@ -13,6 +13,7 @@
   "scripts": {
     "build": "exit 0",
     "test": "ava",
+    "test:xs-worker": "ava test/workers/test-worker.js -m 'xs vat manager'",
     "pretty-fix": "prettier --write '**/*.js'",
     "pretty-check": "prettier --check '**/*.js'",
     "lint-fix": "yarn lint --fix",
diff --git a/packages/xs-vat-worker/.gitignore b/packages/xs-vat-worker/.gitignore
index 3fe6843e9516..596053c39620 100644
--- a/packages/xs-vat-worker/.gitignore
+++ b/packages/xs-vat-worker/.gitignore
@@ -1,2 +1,3 @@
 .envrc
 build/
+compartmap.json
diff --git a/packages/xs-vat-worker/compartmap.json b/packages/xs-vat-worker/compartmap.json
deleted file mode 100644
index cf92f1567079..000000000000
--- a/packages/xs-vat-worker/compartmap.json
+++ /dev/null
@@ -1,127 +0,0 @@
-{
-  "main": "packages/xs-vat-worker/",
-  "compartments": {
-    "packages/xs-vat-worker/": {
-      "label": "@agoric/xs-vat-worker@0.1.0",
-      "location": "packages/xs-vat-worker/",
-      "contents": [
-        "./src/vatWorker.js"
-      ],
-      "modules": {
-        "@agoric/import-bundle": {
-          "compartment": "node_modules/@agoric/import-bundle/",
-          "module": "./src/index.js"
-        },
-        "@agoric/marshal": {
-          "compartment": "node_modules/@agoric/marshal/",
-          "module": "./marshal.js"
-        },
-        "@agoric/swingset-vat/src/kernel/liveSlots": {
-          "compartment": "node_modules/@agoric/swingset-vat/",
-          "module": "./src/kernel/liveSlots.js"
-        }
-      }
-    },
-    "node_modules/@agoric/import-bundle/": {
-      "label": "@agoric/import-bundle@0.0.8",
-      "location": "node_modules/@agoric/import-bundle/",
-      "contents": [
-        "./src/index.js",
-        "./src/compartment-wrapper.js"
-      ],
-      "modules": {}
-    },
-    "node_modules/@agoric/marshal/": {
-      "label": "@agoric/marshal@0.2.3",
-      "location": "node_modules/@agoric/marshal/",
-      "contents": [
-        "./marshal.js"
-      ],
-      "modules": {
-        "@agoric/nat": {
-          "compartment": "node_modules/@agoric/nat/",
-          "module": "./dist/nat.esm.js"
-        },
-        "@agoric/promise-kit": {
-          "compartment": "node_modules/@agoric/promise-kit/",
-          "module": "./src/promiseKit.js"
-        }
-      }
-    },
-    "node_modules/@agoric/swingset-vat/": {
-      "label": "@agoric/swingset-vat@0.6.0",
-      "location": "node_modules/@agoric/swingset-vat/",
-      "contents": [
-        "./src/kernel/liveSlots.js",
-        "./src/parseVatSlots.js",
-        "./src/capdata.js"
-      ],
-      "modules": {
-        "@agoric/marshal": {
-          "compartment": "node_modules/@agoric/marshal/",
-          "module": "./marshal.js"
-        },
-        "@agoric/assert": {
-          "compartment": "node_modules/@agoric/assert/",
-          "module": "./src/assert.js"
-        },
-        "@agoric/promise-kit": {
-          "compartment": "node_modules/@agoric/promise-kit/",
-          "module": "./src/promiseKit.js"
-        },
-        "@agoric/nat": {
-          "compartment": "node_modules/@agoric/nat/",
-          "module": "./dist/nat.esm.js"
-        }
-      }
-    },
-    "node_modules/@agoric/nat/": {
-      "label": "@agoric/nat@2.0.1",
-      "location": "node_modules/@agoric/nat/",
-      "contents": [
-        "./dist/nat.esm.js"
-      ],
-      "modules": {}
-    },
-    "node_modules/@agoric/promise-kit/": {
-      "label": "@agoric/promise-kit@0.1.3",
-      "location": "node_modules/@agoric/promise-kit/",
-      "contents": [
-        "./src/promiseKit.js"
-      ],
-      "modules": {}
-    },
-    "node_modules/@agoric/assert/": {
-      "label": "@agoric/assert@0.0.8",
-      "location": "node_modules/@agoric/assert/",
-      "contents": [
-        "./src/assert.js",
-        "./src/types.js"
-      ],
-      "modules": {}
-    }
-  },
-  "modules": {
-    "node_modules/0_MKDIR": "$(ROOT)/node_modules/0_MKDIR",
-    "node_modules/@agoric/0_MKDIR": "$(ROOT)/node_modules/@agoric/0_MKDIR",
-    "node_modules/@agoric/assert/0_MKDIR": "$(ROOT)/node_modules/@agoric/assert/0_MKDIR",
-    "node_modules/@agoric/assert/src/assert": "$(ROOT)/node_modules/@agoric/assert/src/assert",
-    "node_modules/@agoric/assert/src/types": "$(ROOT)/node_modules/@agoric/assert/src/types",
-    "node_modules/@agoric/import-bundle/0_MKDIR": "$(ROOT)/node_modules/@agoric/import-bundle/0_MKDIR",
-    "node_modules/@agoric/import-bundle/src/compartment-wrapper": "$(ROOT)/node_modules/@agoric/import-bundle/src/compartment-wrapper",
-    "node_modules/@agoric/import-bundle/src/index": "$(ROOT)/node_modules/@agoric/import-bundle/src/index",
-    "node_modules/@agoric/marshal/marshal": "$(ROOT)/node_modules/@agoric/marshal/marshal",
-    "node_modules/@agoric/nat/0_MKDIR": "$(ROOT)/node_modules/@agoric/nat/0_MKDIR",
-    "node_modules/@agoric/nat/dist/nat.esm": "$(ROOT)/node_modules/@agoric/nat/dist/nat.esm",
-    "node_modules/@agoric/promise-kit/0_MKDIR": "$(ROOT)/node_modules/@agoric/promise-kit/0_MKDIR",
-    "node_modules/@agoric/promise-kit/src/promiseKit": "$(ROOT)/node_modules/@agoric/promise-kit/src/promiseKit",
-    "node_modules/@agoric/swingset-vat/0_MKDIR": "$(ROOT)/node_modules/@agoric/swingset-vat/0_MKDIR",
-    "node_modules/@agoric/swingset-vat/src/0_MKDIR": "$(ROOT)/node_modules/@agoric/swingset-vat/src/0_MKDIR",
-    "node_modules/@agoric/swingset-vat/src/capdata": "$(ROOT)/node_modules/@agoric/swingset-vat/src/capdata",
-    "node_modules/@agoric/swingset-vat/src/kernel/liveSlots": "$(ROOT)/node_modules/@agoric/swingset-vat/src/kernel/liveSlots",
-    "node_modules/@agoric/swingset-vat/src/parseVatSlots": "$(ROOT)/node_modules/@agoric/swingset-vat/src/parseVatSlots",
-    "packages/0_MKDIR": "$(ROOT)/packages/0_MKDIR",
-    "packages/xs-vat-worker/0_MKDIR": "$(ROOT)/packages/xs-vat-worker/0_MKDIR",
-    "packages/xs-vat-worker/src/vatWorker": "$(ROOT)/packages/xs-vat-worker/src/vatWorker"
-  }
-}
diff --git a/packages/xs-vat-worker/package.json b/packages/xs-vat-worker/package.json
index 3d343d29bac3..ac39a6e9cf36 100644
--- a/packages/xs-vat-worker/package.json
+++ b/packages/xs-vat-worker/package.json
@@ -5,6 +5,7 @@
   "main": "src/locate.js",
   "module": "src/locate.js",
   "scripts": {
+    "install:xs-lin": "make -f xs-lin.mk install-deps",
     "build:xs-lin": "make -f xs-lin.mk",
     "test": "ava",
     "build": "exit 0",
diff --git a/packages/xs-vat-worker/xs-lin.mk b/packages/xs-vat-worker/xs-lin.mk
index dc169ef21a7e..91aa9faeddfd 100644
--- a/packages/xs-vat-worker/xs-lin.mk
+++ b/packages/xs-vat-worker/xs-lin.mk
@@ -3,6 +3,19 @@ TOOLS=$(MODDABLE)/build/bin/lin/release/
 NODE_MODULES=$(PWD)/node_modules
 ROOT=$(PWD)/../..
 
+.PHONY: all
+
+all:
+	$(MAKE) -f xs-lin.mk build
+	@echo "### building XS tools (headless)"
+	$(MAKE) -f xs-lin.mk $(TOOLS)/mcconfig
+	@echo "### building compartmap.json"
+	$(MAKE) -f xs-lin.mk compartmap.json
+	cat compartmap.json
+	@echo "### building xs-worker"
+	ROOT=$(ROOT) PATH=$(TOOLS):$$PATH MODDABLE=$(MODDABLE) mcconfig -o build -p x-cli-lin -m -d
+
+
 build/bin/lin/debug/xs-vat-worker: build $(TOOLS)/mcconfig moddable/xs/platforms/lin_xs_cli.c compartmap.json manifest.json
 	ROOT=$(ROOT) PATH=$(TOOLS):$$PATH MODDABLE=$(MODDABLE) mcconfig -o build -p x-cli-lin -m -d
 
@@ -20,14 +33,19 @@ moddable/xs/platforms/lin_xs_cli.c: moddable/xs/platforms/lin_xs.h
 
 moddable/xs/platforms/lin_xs.h: /usr/include/glib-2.0/gio/gio.h
 
+.PHONY: install-deps
+install-deps:
+	$(MAKE) -f xs-lin.mk install-gio
+
 .PHONY: install-gio
 /usr/include/glib-2.0/gio/gio.h:
-	@echo "GIO not installed, need root to run apt-get install libgio2.0-dev
+	@echo "GIO not installed, need root to run apt-get install libgio2.0-dev"
 	@echo "feel free to stop now and run `make install-gio` directly, then rebuild"
-	$(MAKE) install-gio
+	$(MAKE) -f xs-lin.mk  install-gio
 
+# ubuntu 'bionic' puts gio in libglib2.0-dev
 install-gio:
-	sudo apt-get -y update && sudo apt-get -y install libgio2.0-dev
+	sudo apt-get -y update && sudo apt-get -y install libglib2.0-dev
 
 $(TOOLS)/mcconfig:
 	cd moddable && \