diff --git a/.github/workflows/test-all-packages.yml b/.github/workflows/test-all-packages.yml
index f674220d276a..f010300699f5 100644
--- a/.github/workflows/test-all-packages.yml
+++ b/.github/workflows/test-all-packages.yml
@@ -203,6 +203,8 @@ jobs:
         run: cd packages/swingset-liveslots && yarn ${{ steps.vars.outputs.test }} | $TEST_COLLECT
       - name: yarn test (swingset-xsnap-supervisor)
         run: cd packages/swingset-xsnap-supervisor && yarn ${{ steps.vars.outputs.test }} | $TEST_COLLECT
+      - name: yarn test (swingset-worker-xsnap-v1)
+        run: cd packages/swingset-worker-xsnap-v1 && yarn ${{ steps.vars.outputs.test }} | $TEST_COLLECT
 
         # The meta-test!
       - name: Check for untested packages
diff --git a/packages/SwingSet/misc-tools/replay-transcript.js b/packages/SwingSet/misc-tools/replay-transcript.js
index 8484b49d6a87..8585dd44495c 100644
--- a/packages/SwingSet/misc-tools/replay-transcript.js
+++ b/packages/SwingSet/misc-tools/replay-transcript.js
@@ -1,5 +1,6 @@
 /* global WeakRef FinalizationRegistry */
 /* eslint-disable no-constant-condition */
+/* eslint-disable import/no-extraneous-dependencies */
 import fs from 'fs';
 // import '@endo/init';
 import '../tools/install-ses-debug.js';
diff --git a/packages/SwingSet/package.json b/packages/SwingSet/package.json
index c4a4f53b3c2d..467b94f368c4 100644
--- a/packages/SwingSet/package.json
+++ b/packages/SwingSet/package.json
@@ -21,6 +21,8 @@
     "lint:eslint": "eslint ."
   },
   "devDependencies": {
+    "@agoric/swingset-xsnap-supervisor": "^0.9.0",
+    "@agoric/xsnap-lockdown": "^0.13.2",
     "@types/better-sqlite3": "^7.5.0",
     "@types/microtime": "^2.1.0",
     "@types/tmp": "^0.2.0",
@@ -34,11 +36,10 @@
     "@agoric/store": "^0.8.3",
     "@agoric/swing-store": "^0.8.1",
     "@agoric/swingset-liveslots": "^0.9.0",
-    "@agoric/swingset-xsnap-supervisor": "^0.9.0",
+    "@agoric/swingset-worker-xsnap-v1": "^0.9.0",
     "@agoric/time": "^0.2.1",
     "@agoric/vat-data": "^0.4.3",
     "@agoric/xsnap": "^0.13.2",
-    "@agoric/xsnap-lockdown": "^0.13.2",
     "@endo/base64": "^0.2.28",
     "@endo/bundle-source": "^2.4.2",
     "@endo/captp": "^2.0.18",
diff --git a/packages/SwingSet/src/controller/startXSnap.js b/packages/SwingSet/src/controller/startXSnap.js
index 8af3552c188f..d42a1f6994d2 100644
--- a/packages/SwingSet/src/controller/startXSnap.js
+++ b/packages/SwingSet/src/controller/startXSnap.js
@@ -1,12 +1,5 @@
-import fs from 'fs';
 import path from 'path';
-import { Fail } from '@agoric/assert';
-import { type as osType } from 'os';
-import { xsnap, recordXSnap } from '@agoric/xsnap';
-import { getLockdownBundle } from '@agoric/xsnap-lockdown';
-import { getSupervisorBundle } from '@agoric/swingset-xsnap-supervisor';
-
-const NETSTRING_MAX_CHUNK_SIZE = 12_000_000;
+import { makeStartXSnapV1 } from '@agoric/swingset-worker-xsnap-v1';
 
 /**
  * @param {{
@@ -20,9 +13,8 @@ const NETSTRING_MAX_CHUNK_SIZE = 12_000_000;
 export function makeStartXSnap(options) {
   // our job is to simply curry some authorities and settings into the
   // 'startXSnap' function we return
-  const { snapStore, spawn, debug = false, traceFile } = options;
-  const { overrideBundles } = options;
 
+  const { traceFile, ...other } = options;
   let serial = 0;
   const makeTraceFile = traceFile
     ? () => {
@@ -32,6 +24,8 @@ export function makeStartXSnap(options) {
       }
     : undefined;
 
+  const startXSnapV1 = makeStartXSnapV1({ makeTraceFile, ...other });
+
   /**
    * @param {string} workerVersion
    * @param {string} vatID
@@ -48,69 +42,11 @@ export function makeStartXSnap(options) {
     metered,
     reload = false,
   ) {
-    await 0; // empty synchronous prelude
-
-    /** @type { import('@agoric/xsnap/src/xsnap').XSnapOptions } */
-    const xsnapOpts = {
-      os: osType(),
-      spawn,
-      stdout: 'inherit',
-      stderr: 'inherit',
-      debug,
-      netstringMaxChunkSize: NETSTRING_MAX_CHUNK_SIZE,
-    };
-
-    let doXSnap = xsnap;
-    if (makeTraceFile) {
-      doXSnap = opts => {
-        const workerTrace = makeTraceFile();
-        console.log('SwingSet xs-worker tracing:', { workerTrace });
-        fs.mkdirSync(workerTrace, { recursive: true });
-        return recordXSnap(opts, workerTrace, {
-          writeFileSync: fs.writeFileSync,
-        });
-      };
-    }
-
-    const meterOpts = metered ? {} : { meteringLimit: 0 };
-    if (snapStore && reload) {
-      // console.log('startXSnap from', { snapshotHash });
-      return snapStore.loadSnapshot(vatID, async snapshot => {
-        const xs = doXSnap({
-          snapshot,
-          name,
-          handleCommand,
-          ...meterOpts,
-          ...xsnapOpts,
-        });
-        await xs.isReady();
-        return xs;
-      });
-    }
-    // console.log('fresh xsnap', { snapStore: snapStore });
-    const worker = doXSnap({ handleCommand, name, ...meterOpts, ...xsnapOpts });
-
-    let bundles = [];
     if (workerVersion === 'xsnap-v1') {
-      // eslint-disable-next-line @jessie.js/no-nested-await
-      bundles.push(await getLockdownBundle());
-      // eslint-disable-next-line @jessie.js/no-nested-await
-      bundles.push(await getSupervisorBundle());
-    } else {
-      throw Error(`unsupported worker version ${workerVersion}`);
-    }
-    if (overrideBundles) {
-      bundles = overrideBundles; // replace the usual bundles
+      return startXSnapV1(vatID, name, handleCommand, metered, reload);
     }
-
-    for (const bundle of bundles) {
-      bundle.moduleFormat === 'getExport' ||
-        bundle.moduleFormat === 'nestedEvaluate' ||
-        Fail`unexpected: ${bundle.moduleFormat}`;
-      // eslint-disable-next-line no-await-in-loop, @jessie.js/no-nested-await
-      await worker.evaluate(`(${bundle.source}\n)()`.trim());
-    }
-    return worker;
+    throw Error(`unsupported worker version ${workerVersion}`);
   }
+
   return startXSnap;
 }
diff --git a/packages/agoric-cli/src/sdk-package-names.js b/packages/agoric-cli/src/sdk-package-names.js
index a07e24bfec8f..93ed550d8210 100644
--- a/packages/agoric-cli/src/sdk-package-names.js
+++ b/packages/agoric-cli/src/sdk-package-names.js
@@ -31,6 +31,7 @@ export default [
   "@agoric/swingset-liveslots",
   "@agoric/swingset-runner",
   "@agoric/swingset-vat",
+  "@agoric/swingset-worker-xsnap-v1",
   "@agoric/swingset-xsnap-supervisor",
   "@agoric/telemetry",
   "@agoric/time",
diff --git a/packages/swingset-worker-xsnap-v1/.gitignore b/packages/swingset-worker-xsnap-v1/.gitignore
new file mode 100644
index 000000000000..1521c8b7652b
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/.gitignore
@@ -0,0 +1 @@
+dist
diff --git a/packages/swingset-worker-xsnap-v1/README.md b/packages/swingset-worker-xsnap-v1/README.md
new file mode 100644
index 000000000000..b7d98c01f600
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/README.md
@@ -0,0 +1,25 @@
+# swingset-worker-xs-v1
+
+This package provides a function to create a "xsnap-v1" SwingSet vat worker.
+
+This worker will include specific (stable) versions of the following components:
+
+* the `xsnap` package (@agoric/xsnap), which includes:
+  * the `xsnap` executable, a C program that combines a specific version of the XS JavaScript runtime, and a driver program (`xsnap.c`) that accepts command messages over a socket
+  * a JS library to launch that program as a child process, and then send/receive messages over the socket
+* a "lockdown bundle" (@agoric/xsnap-lockdown), which can be evaluated inside the xsnap program, to transform the plain (unsecured) JS environment into our preferred (secure) SES/Endo environment, by taming the global constructors, removing ambient authority, and creating the `Compartment` constructor
+* a "supervisor bundle", which can be evaluated after lockdown, to hook into the globally-registered handler function to accept delivery messages
+  * this imports a specific version of "@agoric/swingset-liveslots", to create the object-capability / distributed-messaging environment, which can route messages through syscalls, and provide virtual/durable object support
+
+By importing `@agoric/swingset-worker-xsnap-v1`, the kernel will get a stable behavior from the worker (including consistent heap snapshot contents), regardless of changes to other packages, or behavior-neutral changes to the kernel itself. Any two kernels which use `xsnap-v1` and make the same sequence of deliveries (and syscalls responses) should get the same XS state, the same syscalls, the same metering, and the same XS heap snapshot hash.
+
+To guard against accidental changes to the `@agoric/swingset-worker-xsnap-v1` package (perhaps yarn.lock being insufficient to lock down the bundle package versions correctly), the API can also return a hash string that describes the contents of the bundles. The kernel code that imports this module can compare this string against hard-coded values, which would only be changed when deliberately switching to a new version of the worker.
+
+The intention is for the `@agoric/swingset-worker-xsnap-v1` package to be published to NPM only once: we publish version 1.0.0 and then never publish again. Any new changes would go into a new `@agoric/swingset-worker-xsnap-v2` package (of which we'd only ever publish 1.0.0 as well), etc.
+
+We will figure out a different approach for "dev" development, where downstream clients want to use unstable/recent versions instead. Follow https://github.com/Agoric/agoric-sdk/issues/7056 for details.
+
+## API
+
+The primary export is a function named `makeStartXSnapV1()`. This takes a set of authorities (the snapStore, `env`, and a `spawn` function) and returns a `startXSnapV1()` function. This latter function encapsulates all the components listed above.
+
diff --git a/packages/swingset-worker-xsnap-v1/jsconfig.json b/packages/swingset-worker-xsnap-v1/jsconfig.json
new file mode 100644
index 000000000000..b7cc9a19a3bd
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/jsconfig.json
@@ -0,0 +1,12 @@
+// This file can contain .js-specific Typescript compiler config.
+{
+  "extends": "../../tsconfig.json",
+  "include": [
+    "*.js",
+    "lib/**/*.js",
+    "src/**/*.d.ts",
+    "src/**/*.js",
+    "test/**/*.js",
+    "tools/**/*.js",
+  ],
+}
diff --git a/packages/swingset-worker-xsnap-v1/package.json b/packages/swingset-worker-xsnap-v1/package.json
new file mode 100644
index 000000000000..d728206a6261
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "@agoric/swingset-worker-xsnap-v1",
+  "version": "0.9.0",
+  "description": "make swingset xsnap-v1 workers",
+  "author": "Agoric",
+  "license": "Apache-2.0",
+  "type": "module",
+  "main": "./src/index.js",
+  "scripts": {
+    "build": "exit 0",
+    "clean": "exit 0",
+    "lint": "run-s --continue-on-error lint:*",
+    "lint:js": "eslint 'src/**/*.js' 'test/**/*.js'",
+    "lint:types": "tsc -p jsconfig.json",
+    "lint-fix": "eslint --fix 'src/**/*.js' 'test/**/*.js'",
+    "test": "ava",
+    "test:c8": "c8 $C8_OPTIONS ava --config=ava-nesm.config.js",
+    "test:xs": "exit 0"
+  },
+  "dependencies": {
+    "@agoric/assert": "^0.5.1",
+    "@agoric/swingset-xsnap-supervisor": "^0.9.0",
+    "@agoric/xsnap": "^0.13.2",
+    "@agoric/xsnap-lockdown": "^0.13.2"
+  },
+  "devDependencies": {
+    "@endo/bundle-source": "^2.4.2",
+    "@endo/init": "^0.5.52",
+    "@endo/marshal": "^0.8.1",
+    "ava": "^5.1.0",
+    "c8": "^7.12.0"
+  },
+  "files": [
+    "LICENSE*",
+    "src"
+  ],
+  "publishConfig": {
+    "access": "public"
+  },
+  "ava": {
+    "files": [
+      "test/**/test-*.js"
+    ],
+    "timeout": "2m",
+    "workerThreads": false
+  }
+}
diff --git a/packages/swingset-worker-xsnap-v1/src/index.js b/packages/swingset-worker-xsnap-v1/src/index.js
new file mode 100644
index 000000000000..1b7809749dec
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/src/index.js
@@ -0,0 +1 @@
+export { makeStartXSnapV1 } from './make-v1.js';
diff --git a/packages/swingset-worker-xsnap-v1/src/make-v1.js b/packages/swingset-worker-xsnap-v1/src/make-v1.js
new file mode 100644
index 000000000000..2d8c6a0fdc0a
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/src/make-v1.js
@@ -0,0 +1,108 @@
+import fs from 'fs';
+import { Fail } from '@agoric/assert';
+import { type as osType } from 'os';
+import { xsnap, recordXSnap } from '@agoric/xsnap';
+import { getLockdownBundle } from '@agoric/xsnap-lockdown';
+import { getSupervisorBundle } from '@agoric/swingset-xsnap-supervisor';
+
+const NETSTRING_MAX_CHUNK_SIZE = 12_000_000;
+
+/**
+ * SnapStore is defined by swing-store, but we don't import that: we get it
+ * from swingset as an option. To avoid an inconvenient dependency graph,
+ * we define the salient methods locally.
+ *
+ * @typedef {<T>(vatID: string, loadRaw: (filePath: string) => Promise<T>) => Promise<T>} LoadSnapshot
+ * @typedef {{ loadSnapshot: LoadSnapshot }} SnapStore
+ */
+/**
+ * @param {{
+ *   snapStore?: SnapStore,
+ *   spawn: typeof import('child_process').spawn
+ *   debug?: boolean,
+ *   makeTraceFile?: () => string,
+ *   overrideBundles?: { moduleFormat: string, source: string }[],
+ * }} options
+ */
+export function makeStartXSnapV1(options) {
+  // our job is to simply curry some authorities and settings into the
+  // 'startXSnapV1' function we return
+  const { snapStore, spawn, debug = false, makeTraceFile } = options;
+  const { overrideBundles } = options;
+
+  /**
+   * @param {string} vatID
+   * @param {string} name
+   * @param {(request: Uint8Array) => Promise<Uint8Array>} handleCommand
+   * @param {boolean} [metered]
+   * @param {boolean} [reload]
+   */
+  async function startXSnapV1(
+    vatID,
+    name,
+    handleCommand,
+    metered,
+    reload = false,
+  ) {
+    await 0; // empty synchronous prelude
+
+    /** @type { import('@agoric/xsnap/src/xsnap').XSnapOptions } */
+    const xsnapOpts = {
+      os: osType(),
+      spawn,
+      stdout: 'inherit',
+      stderr: 'inherit',
+      debug,
+      netstringMaxChunkSize: NETSTRING_MAX_CHUNK_SIZE,
+    };
+
+    let doXSnap = xsnap;
+    if (makeTraceFile) {
+      doXSnap = opts => {
+        const workerTrace = makeTraceFile();
+        console.log('SwingSet xs-worker tracing:', { workerTrace });
+        fs.mkdirSync(workerTrace, { recursive: true });
+        return recordXSnap(opts, workerTrace, {
+          writeFileSync: fs.writeFileSync,
+        });
+      };
+    }
+
+    const meterOpts = metered ? {} : { meteringLimit: 0 };
+    if (snapStore && reload) {
+      // console.log('startXSnap from', { snapshotHash });
+      return snapStore.loadSnapshot(vatID, async snapshot => {
+        const xs = doXSnap({
+          snapshot,
+          name,
+          handleCommand,
+          ...meterOpts,
+          ...xsnapOpts,
+        });
+        await xs.isReady();
+        return xs;
+      });
+    }
+    // console.log('fresh xsnap', { snapStore: snapStore });
+    const worker = doXSnap({ handleCommand, name, ...meterOpts, ...xsnapOpts });
+
+    let bundles = [];
+    // eslint-disable-next-line @jessie.js/no-nested-await
+    bundles.push(await getLockdownBundle());
+    // eslint-disable-next-line @jessie.js/no-nested-await
+    bundles.push(await getSupervisorBundle());
+    if (overrideBundles) {
+      bundles = overrideBundles; // replace the usual bundles
+    }
+
+    for (const bundle of bundles) {
+      bundle.moduleFormat === 'getExport' ||
+        bundle.moduleFormat === 'nestedEvaluate' ||
+        Fail`unexpected: ${bundle.moduleFormat}`;
+      // eslint-disable-next-line no-await-in-loop, @jessie.js/no-nested-await
+      await worker.evaluate(`(${bundle.source}\n)()`.trim());
+    }
+    return worker;
+  }
+  return startXSnapV1;
+}
diff --git a/packages/swingset-worker-xsnap-v1/test/test-worker.js b/packages/swingset-worker-xsnap-v1/test/test-worker.js
new file mode 100644
index 000000000000..54279276b3c9
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/test/test-worker.js
@@ -0,0 +1,104 @@
+import test from 'ava';
+import '@endo/init/debug.js';
+
+import { spawn } from 'child_process';
+import bundleSource from '@endo/bundle-source';
+import { makeMarshal } from '@endo/marshal';
+import { Fail } from '@agoric/assert';
+import { makeStartXSnapV1 } from '../src/index.js';
+
+const nope = () => Fail`nope`;
+const kmarshal = makeMarshal(nope, nope, {
+  serializeBodyFormat: 'smallcaps',
+  errorTagging: 'off',
+});
+const kser = value => kmarshal.serialize(harden(value));
+const kunser = value => kmarshal.unserialize(value);
+
+test('basic delivery', async t => {
+  const fn = new URL('./vat-simple.js', import.meta.url).pathname;
+  const bundle = await bundleSource(fn, { dev: true });
+
+  const snapStore = /** @type {SnapStore} */ undefined;
+  const startXSnapV1 = makeStartXSnapV1({
+    snapStore, // unused by this test
+    spawn,
+  });
+
+  const vatstore = new Map();
+  const resolutions = new Map();
+
+  const vatID = 'v1';
+  const argName = 'v1-name';
+  function handleUpstream(body) {
+    if (body[0] === 'syscall') {
+      let result;
+      const vso = body[1];
+      if (vso[0] === 'vatstoreGet') {
+        result = vatstore.get(vso[1]);
+      } else if (vso[0] === 'vatstoreSet') {
+        vatstore.set(vso[1], vso[2]);
+      } else if (vso[0] === 'vatstoreGetNextKey') {
+        if (vso[1] === 'vom.dkind.') {
+          // liveslots is looking for KindHandles from a previous version
+          result = undefined; // tell it there are none
+        } else {
+          console.log(`unhandled vatstoreGetNextKey`, vso);
+          throw Error('unhandled vatstoreGetNextKey');
+        }
+      } else if (vso[0] === 'resolve') {
+        for (const [vpid, isReject, value] of vso[1]) {
+          resolutions.set(vpid, [isReject, value]);
+        }
+      } else {
+        console.log(`unhandled syscall`, vso);
+        throw Error('unhandled syscall');
+      }
+      return ['ok', result];
+    } else if (body[0] === 'sourcedConsole') {
+      const [_, source, level, value] = body;
+      console.log(`log: ${source} console.${level}: ${value}`);
+    } else {
+      console.log(`unhandled upstream`, body);
+      throw Error('unhandled upstream');
+    }
+    return ['ok'];
+  }
+  const encoder = new TextEncoder();
+  const decoder = new TextDecoder();
+  async function handleCommand(msg) {
+    const tagged = handleUpstream(JSON.parse(decoder.decode(msg)));
+    return encoder.encode(JSON.stringify(tagged));
+  }
+  const metered = false;
+  const worker = await startXSnapV1(vatID, argName, handleCommand, metered);
+  console.log(`-- started worker`);
+
+  const liveSlotsOptions = {};
+  const setBundle = ['setBundle', vatID, bundle, liveSlotsOptions];
+  const sbResult = await worker.issueStringCommand(JSON.stringify(setBundle));
+  t.deepEqual(JSON.parse(sbResult.reply), ['dispatchReady']);
+
+  // liveslots does a bunch of vatstore operations during startVat
+  const vdoStartVat = ['startVat', kser()];
+  const deliverStartVat = ['deliver', vdoStartVat];
+  const dResult = await worker.issueStringCommand(
+    JSON.stringify(deliverStartVat),
+  );
+  t.deepEqual(JSON.parse(dResult.reply), ['ok', null, null]);
+
+  const pingMethargsBody = JSON.stringify(['ping', []]);
+  const vdoPing = [
+    'message',
+    'o+0',
+    { methargs: { body: pingMethargsBody, slots: [] }, result: 'p-1' },
+  ];
+  const deliverPing = ['deliver', vdoPing];
+  const pResult = await worker.issueStringCommand(JSON.stringify(deliverPing));
+  t.deepEqual(JSON.parse(pResult.reply), ['ok', null, null]);
+
+  t.true(resolutions.has('p-1'));
+  const [isReject, value] = resolutions.get('p-1');
+  t.is(isReject, false);
+  t.is(kunser(value), 'pong');
+});
diff --git a/packages/swingset-worker-xsnap-v1/test/vat-simple.js b/packages/swingset-worker-xsnap-v1/test/vat-simple.js
new file mode 100644
index 000000000000..035dbb03c02b
--- /dev/null
+++ b/packages/swingset-worker-xsnap-v1/test/vat-simple.js
@@ -0,0 +1,11 @@
+import { Far } from '@endo/marshal';
+
+export function buildRootObject() {
+  console.log(`--vat: in buildRootObject`);
+  return Far('root', {
+    ping: () => {
+      console.log(`--vat: in ping`);
+      return 'pong';
+    },
+  });
+}