diff --git a/packages/no-trapping-shim/CHANGELOG.md b/packages/no-trapping-shim/CHANGELOG.md
index 436a6104b3..420e6f23d0 100644
--- a/packages/no-trapping-shim/CHANGELOG.md
+++ b/packages/no-trapping-shim/CHANGELOG.md
@@ -1,143 +1 @@
 # Change Log
-
-All notable changes to this project will be documented in this file.
-See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
-
-### [1.1.8](https://github.com/endojs/endo/compare/@endo/skel@1.1.7...@endo/skel@1.1.8) (2024-11-13)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.7](https://github.com/endojs/endo/compare/@endo/skel@1.1.6...@endo/skel@1.1.7) (2024-10-22)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.6](https://github.com/endojs/endo/compare/@endo/skel@1.1.5...@endo/skel@1.1.6) (2024-10-10)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.5](https://github.com/endojs/endo/compare/@endo/skel@1.1.4...@endo/skel@1.1.5) (2024-08-27)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.4](https://github.com/endojs/endo/compare/@endo/skel@1.1.3...@endo/skel@1.1.4) (2024-08-01)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.3](https://github.com/endojs/endo/compare/@endo/skel@1.1.2...@endo/skel@1.1.3) (2024-07-30)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.2](https://github.com/endojs/endo/compare/@endo/skel@1.1.1...@endo/skel@1.1.2) (2024-05-07)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.1.1](https://github.com/endojs/endo/compare/@endo/skel@1.1.0...@endo/skel@1.1.1) (2024-04-04)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-## [1.1.0](https://github.com/endojs/endo/compare/@endo/skel@1.0.4...@endo/skel@1.1.0) (2024-03-20)
-
-
-### Features
-
-* **ses-ava:** import test from @endo/ses-ava/prepare-endo.js ([#2133](https://github.com/endojs/endo/issues/2133)) ([9d3a7ce](https://github.com/endojs/endo/commit/9d3a7ce150b6fd6fe7c8c4cc43da411e981731ac))
-
-
-
-### [1.0.4](https://github.com/endojs/endo/compare/@endo/skel@1.0.3...@endo/skel@1.0.4) (2024-02-23)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.0.3](https://github.com/endojs/endo/compare/@endo/skel@1.0.2...@endo/skel@1.0.3) (2024-02-15)
-
-
-### Bug Fixes
-
-* Add repository directory to all package descriptors ([e5f36e7](https://github.com/endojs/endo/commit/e5f36e7a321c13ee25e74eb74d2a5f3d7517119c))
-
-
-
-### [1.0.2](https://github.com/endojs/endo/compare/@endo/skel@1.0.1...@endo/skel@1.0.2) (2024-01-18)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### [1.0.1](https://github.com/endojs/endo/compare/@endo/skel@1.0.0...@endo/skel@1.0.1) (2023-12-20)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-## [1.0.0](https://github.com/endojs/endo/compare/@endo/skel@0.1.3...@endo/skel@1.0.0) (2023-12-12)
-
-
-### Bug Fixes
-
-* Adjust type generation in release process and CI ([9465be3](https://github.com/endojs/endo/commit/9465be369e53167815ca444f6293a8e9eb48501d))
-
-
-
-### [0.1.3](https://github.com/endojs/endo/compare/@endo/skel@0.1.2...@endo/skel@0.1.3) (2023-09-12)
-
-**Note:** Version bump only for package @endo/skel
-
-
-
-
-
-### 0.1.2 (2023-08-07)
-
-
-### Bug Fixes
-
-* Fix scaffold and transforms yarn pack ([42439e7](https://github.com/endojs/endo/commit/42439e7d452e839b9856eac0e852766c237219d0))
-
-
-
-### 0.1.1 (2023-08-07)
-
-
-### Bug Fixes
-
-* Fix scaffold and transforms yarn pack ([42439e7](https://github.com/endojs/endo/commit/42439e7d452e839b9856eac0e852766c237219d0))
diff --git a/packages/no-trapping-shim/index.js b/packages/no-trapping-shim/index.js
index e69de29bb2..42a68f007b 100644
--- a/packages/no-trapping-shim/index.js
+++ b/packages/no-trapping-shim/index.js
@@ -0,0 +1 @@
+export * from './src/no-trapping-pony.js';
diff --git a/packages/no-trapping-shim/package.json b/packages/no-trapping-shim/package.json
index c76480f1b2..42c20f99de 100644
--- a/packages/no-trapping-shim/package.json
+++ b/packages/no-trapping-shim/package.json
@@ -2,7 +2,7 @@
   "name": "@endo/no-trapping-shim",
   "version": "0.1.0",
   "private": true,
-  "description": null,
+  "description": "shim and ponyfill for no-trapping integrity level",
   "keywords": [],
   "author": "Endo contributors",
   "license": "Apache-2.0",
@@ -20,6 +20,7 @@
   "module": "./index.js",
   "exports": {
     ".": "./index.js",
+    "./shim.js": "./shim.js",
     "./package.json": "./package.json"
   },
   "scripts": {
@@ -35,10 +36,7 @@
     "test:c8": "c8 $C8_OPTIONS ava --config=ava-nesm.config.js",
     "test:xs": "exit 0"
   },
-  "dependencies": {},
   "devDependencies": {
-    "@endo/lockdown": "workspace:^",
-    "@endo/ses-ava": "workspace:^",
     "ava": "^6.1.3",
     "c8": "^7.14.0",
     "tsd": "^0.31.2",
diff --git a/packages/no-trapping-shim/shim.js b/packages/no-trapping-shim/shim.js
new file mode 100644
index 0000000000..b20931f038
--- /dev/null
+++ b/packages/no-trapping-shim/shim.js
@@ -0,0 +1,10 @@
+/* global globalThis */
+import { ReflectPlus, ObjectPlus, ProxyPlus } from './src/no-trapping-pony.js';
+
+globalThis.Reflect = ReflectPlus;
+
+globalThis.Object = ObjectPlus;
+// eslint-disable-next-line no-extend-native
+Object.prototype.constructor = ObjectPlus;
+
+globalThis.Proxy = ProxyPlus;
diff --git a/packages/no-trapping-shim/src/no-trapping-pony.js b/packages/no-trapping-shim/src/no-trapping-pony.js
new file mode 100644
index 0000000000..5b3d356225
--- /dev/null
+++ b/packages/no-trapping-shim/src/no-trapping-pony.js
@@ -0,0 +1,278 @@
+const OriginalObject = Object;
+const OriginalReflect = Reflect;
+const OriginalProxy = Proxy;
+const { freeze, defineProperty, hasOwn } = OriginalObject;
+const { apply, construct, ownKeys } = OriginalReflect;
+
+const noTrappingSet = new WeakSet();
+
+const proxyHandlerMap = new WeakMap();
+
+const isPrimitive = specimen => OriginalObject(specimen) !== specimen;
+
+/**
+ * Corresponds to the internal function shared by `Object.isNoTrapping` and
+ * `Reflect.isNoTrapping`.
+ *
+ * @param {any} specimen
+ * @param {boolean} shouldThrow
+ * @returns {boolean}
+ */
+const isNoTrappingInternal = (specimen, shouldThrow) => {
+  if (noTrappingSet.has(specimen)) {
+    return true;
+  }
+  if (!proxyHandlerMap.has(specimen)) {
+    return false;
+  }
+  const [target, handler] = proxyHandlerMap.get(specimen);
+  if (isNoTrappingInternal(target, shouldThrow)) {
+    noTrappingSet.add(specimen);
+    return true;
+  }
+  const trap = handler.isNoTrapping;
+  if (trap === undefined) {
+    return false;
+  }
+  const result = apply(trap, handler, [target]);
+  const ofTarget = isNoTrappingInternal(target, shouldThrow);
+  if (result !== ofTarget) {
+    if (shouldThrow) {
+      throw TypeError(
+        `'isNoTrapping' proxy trap does not reflect 'isNoTrapping' of proxy target (which is '${ofTarget}')`,
+      );
+    }
+    return false;
+  }
+  if (result) {
+    noTrappingSet.add(specimen);
+  }
+  return result;
+};
+
+/**
+ *  Corresponds to the internal function shared by `Object.suppressTrapping` and
+ * `Reflect.suppressTrapping`.
+ *
+ * @param {any} specimen
+ * @param {boolean} shouldThrow
+ * @returns {boolean}
+ */
+const suppressTrappingInternal = (specimen, shouldThrow) => {
+  if (noTrappingSet.has(specimen)) {
+    return true;
+  }
+  freeze(specimen);
+  if (!proxyHandlerMap.has(specimen)) {
+    noTrappingSet.add(specimen);
+    return true;
+  }
+  const [target, handler] = proxyHandlerMap.get(specimen);
+  if (isNoTrappingInternal(target, shouldThrow)) {
+    noTrappingSet.add(specimen);
+    return true;
+  }
+  const trap = handler.suppressTrapping;
+  if (trap === undefined) {
+    const result = suppressTrappingInternal(target, shouldThrow);
+    if (result) {
+      noTrappingSet.add(specimen);
+    }
+    return result;
+  }
+  const result = apply(trap, handler, [target]);
+  const ofTarget = isNoTrappingInternal(target, shouldThrow);
+  if (result !== ofTarget) {
+    if (shouldThrow) {
+      throw TypeError(
+        `'suppressTrapping' proxy trap does not reflect 'isNoTrapping' of proxy target (which is '${ofTarget}')`,
+      );
+    }
+    return false;
+  }
+  if (result) {
+    noTrappingSet.add(specimen);
+  }
+  return result;
+};
+
+export const extraReflectMethods = freeze({
+  isNoTrapping(target) {
+    if (isPrimitive(target)) {
+      throw TypeError('Reflect.isNoTrapping called on non-object');
+    }
+    return isNoTrappingInternal(target, false);
+  },
+  suppressTrapping(target) {
+    if (isPrimitive(target)) {
+      throw TypeError('Reflect.suppressTrapping called on non-object');
+    }
+    return suppressTrappingInternal(target, false);
+  },
+});
+
+export const extraObjectMethods = freeze({
+  isNoTrapping(target) {
+    if (isPrimitive(target)) {
+      return true;
+    }
+    return isNoTrappingInternal(target, true);
+  },
+  suppressTrapping(target) {
+    if (isPrimitive(target)) {
+      return target;
+    }
+    if (suppressTrappingInternal(target, true)) {
+      return target;
+    }
+    throw TypeError('preventExtensions trap returned falsy');
+  },
+});
+
+const addExtras = (base, ...extrasArgs) => {
+  for (const extras of extrasArgs) {
+    for (const key of ownKeys(extras)) {
+      if (base[key] !== extras[key]) {
+        defineProperty(base, key, {
+          value: extras[key],
+          writable: true,
+          enumerable: false,
+          configurable: true,
+        });
+      }
+    }
+  }
+};
+
+/** In the shim, `ReflectPlus` replaces the global `Reflect`. */
+const ReflectPlus = {};
+addExtras(ReflectPlus, OriginalReflect, extraReflectMethods);
+export { ReflectPlus };
+
+/**
+ * In the shim, `ObjectPlus` replaces the global `Object`.
+ *
+ * @type {ObjectConstructor}
+ */
+// @ts-expect-error TS does not know the rest of the type is added below
+const ObjectPlus = function Object(...args) {
+  if (new.target) {
+    return construct(OriginalObject, args, new.target);
+  } else {
+    return apply(OriginalObject, this, args);
+  }
+};
+// @ts-expect-error We actually can assign to its `.prototype`.
+ObjectPlus.prototype = OriginalObject.prototype;
+addExtras(ObjectPlus, OriginalObject, extraObjectMethods);
+export { ObjectPlus };
+
+const metaHandler = freeze({
+  get(_, trapName, handlerPlus) {
+    /**
+     * The `trapPlus` method is an enhanced version of
+     * `originalHandler[trapName]`. If the handlerPlus has no own `trapName`
+     * property, then the `get` of the metaHandler is called, which returns
+     * the `trapPlus`, which is then called as the trap of the returned
+     * proxyPlus. When so called, it installs an own `handlerPlus[trapName]`
+     * which is either `undefined` or this same `trapPlus`, to avoid further
+     * need to meta-handle that `handlerPlus[trapName]`.
+     *
+     * @param {any} target
+     * @param {any[]} rest
+     */
+    const trapPlus = freeze((target, ...rest) => {
+      if (isNoTrappingInternal(target, true)) {
+        defineProperty(handlerPlus, trapName, {
+          value: undefined,
+          writable: false,
+          enumerable: true,
+          configurable: false,
+        });
+      } else {
+        if (!hasOwn(handlerPlus, trapName)) {
+          defineProperty(handlerPlus, trapName, {
+            value: trapPlus,
+            writable: false,
+            enumerable: true,
+            configurable: true,
+          });
+        }
+        const { originalHandler } = handlerPlus;
+        const trap = originalHandler[trapName];
+        if (trap !== undefined) {
+          // Note that whether `trap === undefined` can change dynamically,
+          // so we do not install an own `handlerPlus[trapName] === undefined`
+          // for that case. We still install or preserve an own
+          // `handlerPlus[trapName] === trapPlus` until the target is
+          // seen to be non-trapping.
+          return apply(trap, originalHandler, [target, ...rest]);
+        }
+      }
+      return ReflectPlus[trapName](target, ...rest);
+    });
+    return trapPlus;
+  },
+});
+
+/**
+ * A handlerPlus starts as a fresh empty object that inherits from a proxy
+ * whose handler is the shared generic metaHandler.
+ * Thus, the metaHandler's `get` method is called only when the
+ * `handlerPlus` does not have a property overriding that `trapName`.
+ * In that case, the metaHandler's `get` is called with its `receiver`
+ * being the `handlerPlus`.
+ *
+ * @param {ProxyHandler<any>} originalHandler
+ * @returns {ProxyHandler<any> & {
+ *   isNoTrapping: (target: any) => boolean,
+ *   suppressTrapping: (target: any) => boolean,
+ *   originalHandler: ProxyHandler<any>
+ * }}
+ */
+const makeHandlerPlus = originalHandler => ({
+  // @ts-expect-error TS does not know what this __proto__ is doing
+  __proto__: new OriginalProxy({}, metaHandler),
+  // relies on there never being a trap named `originalHandler`.
+  originalHandler,
+});
+
+/**
+ * In the shim, `ProxyPlus` replaces the global `Proxy`.
+ *
+ * @type {ProxyConstructor}
+ */
+// @ts-expect-error We reject non-new calls in the body
+const ProxyPlus = function Proxy(target, handler) {
+  // @ts-expect-error Yes, we mean to compare these.
+  if (new.target !== ProxyPlus) {
+    if (new.target === undefined) {
+      throw TypeError('Proxy constructor requires "new"');
+    }
+    throw TypeError('Safe Proxy shim does not support subclassing');
+  }
+  const handlerPlus = makeHandlerPlus(handler);
+  const proxy = new OriginalProxy(target, handlerPlus);
+  proxyHandlerMap.set(proxy, [target, handler]);
+  return proxy;
+};
+// The `OriginalProxy` is both constructible (i.e., responsive to `new`) and
+// lacks a `prototype` property. The closest we can come to this is to set
+// `ProxyPlus.prototype` to `undefined`
+ProxyPlus.prototype = undefined;
+ProxyPlus.revocable = (target, handler) => {
+  const handlerPlus = makeHandlerPlus(handler);
+  const { proxy, revoke } = OriginalProxy.revocable(target, handlerPlus);
+  proxyHandlerMap.set(proxy, [target, handler]);
+  return {
+    proxy,
+    revoke() {
+      if (isNoTrappingInternal(target, true)) {
+        throw TypeError('Cannot revoke non-trapping proxy');
+      }
+      revoke();
+    },
+  };
+};
+
+export { ProxyPlus };
diff --git a/packages/no-trapping-shim/test/index.test.js b/packages/no-trapping-shim/test/index.test.js
deleted file mode 100644
index bf5a26862c..0000000000
--- a/packages/no-trapping-shim/test/index.test.js
+++ /dev/null
@@ -1,5 +0,0 @@
-import test from '@endo/ses-ava/prepare-endo.js';
-
-test('placeholder', async t => {
-  t.fail('TODO: add tests');
-});
diff --git a/packages/no-trapping-shim/test/no-trapping-pony.test.js b/packages/no-trapping-shim/test/no-trapping-pony.test.js
new file mode 100644
index 0000000000..15a2c385ff
--- /dev/null
+++ b/packages/no-trapping-shim/test/no-trapping-pony.test.js
@@ -0,0 +1,29 @@
+// Uses 'ava' rather than @endo/ses-ava to avoid worries about cyclic
+// dependencies. We will need similar tests is higher level packages, in order
+// to test compat with ses and ses-ava.
+import test from 'ava';
+import { ReflectPlus, ProxyPlus } from '../src/no-trapping-pony.js';
+
+const { freeze, isFrozen } = Object;
+
+test('no-trapping-pony', async t => {
+  const specimen = { foo: 8 };
+
+  const sillyHandler = freeze({
+    get(target, prop, receiver) {
+      return [target, prop, receiver];
+    },
+  });
+
+  const safeProxy = new ProxyPlus(specimen, sillyHandler);
+
+  t.false(ReflectPlus.isNoTrapping(specimen));
+  t.false(isFrozen(specimen));
+  t.deepEqual(safeProxy.foo, [specimen, 'foo', safeProxy]);
+
+  t.true(ReflectPlus.suppressTrapping(specimen));
+
+  t.true(ReflectPlus.isNoTrapping(specimen));
+  t.true(isFrozen(specimen));
+  t.deepEqual(safeProxy.foo, 8);
+});
diff --git a/packages/no-trapping-shim/test/no-trapping-shim.test.js b/packages/no-trapping-shim/test/no-trapping-shim.test.js
new file mode 100644
index 0000000000..b6ac48c25d
--- /dev/null
+++ b/packages/no-trapping-shim/test/no-trapping-shim.test.js
@@ -0,0 +1,29 @@
+// Uses 'ava' rather than @endo/ses-ava to avoid worries about cyclic
+// dependencies. We will need similar tests is higher level packages, in order
+// to test compat with ses and ses-ava.
+import test from 'ava';
+import '../shim.js';
+
+const { freeze, isFrozen } = Object;
+
+test('no-trapping-pony', async t => {
+  const specimen = { foo: 8 };
+
+  const sillyHandler = freeze({
+    get(target, prop, receiver) {
+      return [target, prop, receiver];
+    },
+  });
+
+  const safeProxy = new Proxy(specimen, sillyHandler);
+
+  t.false(Reflect.isNoTrapping(specimen));
+  t.false(isFrozen(specimen));
+  t.deepEqual(safeProxy.foo, [specimen, 'foo', safeProxy]);
+
+  t.true(Reflect.suppressTrapping(specimen));
+
+  t.true(Reflect.isNoTrapping(specimen));
+  t.true(isFrozen(specimen));
+  t.deepEqual(safeProxy.foo, 8);
+});
diff --git a/yarn.lock b/yarn.lock
index a838a69480..9a92741957 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -702,6 +702,17 @@ __metadata:
   languageName: unknown
   linkType: soft
 
+"@endo/no-trapping-shim@workspace:packages/no-trapping-shim":
+  version: 0.0.0-use.local
+  resolution: "@endo/no-trapping-shim@workspace:packages/no-trapping-shim"
+  dependencies:
+    ava: "npm:^6.1.3"
+    c8: "npm:^7.14.0"
+    tsd: "npm:^0.31.2"
+    typescript: "npm:~5.6.3"
+  languageName: unknown
+  linkType: soft
+
 "@endo/pass-style@workspace:^, @endo/pass-style@workspace:packages/pass-style":
   version: 0.0.0-use.local
   resolution: "@endo/pass-style@workspace:packages/pass-style"