diff --git a/packages/ses/NEWS.md b/packages/ses/NEWS.md
index 75df0419a9..c33ba398e3 100644
--- a/packages/ses/NEWS.md
+++ b/packages/ses/NEWS.md
@@ -13,6 +13,8 @@ User-visible changes in `ses`:
   - Node 18, Node 20, and all browsers have `structuredClone`
   - Node <= 16 have neither, but are also no longer supported by Endo.
 - Now exports separate layer for console shim: `ses/console-shim.js`.
+- Adds permits for `ModuleSource`, either the native implementation or from
+  `@endo/module-source/shim.js`.
 
 # v1.8.0 (2024-08-27)
 
diff --git a/packages/ses/src/error/console.js b/packages/ses/src/error/console.js
index 8ad8853805..60ff798d93 100644
--- a/packages/ses/src/error/console.js
+++ b/packages/ses/src/error/console.js
@@ -368,8 +368,10 @@ export const makeCausalConsole = (baseConsole, loggedErrorHandler) => {
     const levelMethod = (...logArgs) => {
       const subErrors = [];
       const argTags = extractErrorArgs(logArgs, subErrors);
-      // eslint-disable-next-line @endo/no-polymorphic-call
-      baseConsole[level](...argTags);
+      if (baseConsole[level]) {
+        // eslint-disable-next-line @endo/no-polymorphic-call
+        baseConsole[level](...argTags);
+      }
       // @ts-expect-error ConsoleProp vs LogSeverity mismatch
       logSubErrors(level, subErrors);
     };
@@ -476,12 +478,16 @@ export const defineCausalConsoleFromLogger = loggedErrorHandler => {
           // the host console will separate them with additional spaces.
           arrayPush(indents, ' ');
         });
+      } else {
+        baseConsole[name] = () => {};
       }
     }
     if (baseConsole.groupEnd) {
       baseConsole.groupEnd = makeNamed('groupEnd', (...args) => {
         arrayPop(indents);
       });
+    } else {
+      baseConsole.groupEnd = () => {};
     }
     harden(baseConsole);
     const causalConsole = makeCausalConsole(
diff --git a/packages/ses/src/lockdown.js b/packages/ses/src/lockdown.js
index 170c341fbc..56f5bcad0d 100644
--- a/packages/ses/src/lockdown.js
+++ b/packages/ses/src/lockdown.js
@@ -46,6 +46,7 @@ import { makeSafeEvaluator } from './make-safe-evaluator.js';
 import { initialGlobalPropertyNames } from './permits.js';
 import { tameFunctionToString } from './tame-function-tostring.js';
 import { tameDomains } from './tame-domains.js';
+import { tameModuleSource } from './tame-module-source.js';
 
 import { tameConsole } from './error/tame-console.js';
 import tameErrorConstructor from './error/tame-error-constructor.js';
@@ -286,6 +287,7 @@ export const repairIntrinsics = (options = {}) => {
   addIntrinsics(tameRegExpConstructor(regExpTaming));
   addIntrinsics(tameSymbolConstructor());
   addIntrinsics(shimArrayBufferTransfer());
+  addIntrinsics(tameModuleSource());
 
   addIntrinsics(getAnonymousIntrinsics());
 
diff --git a/packages/ses/src/permits.js b/packages/ses/src/permits.js
index 585d3c0c3f..dd9eabd55b 100644
--- a/packages/ses/src/permits.js
+++ b/packages/ses/src/permits.js
@@ -101,8 +101,12 @@ export const universalPropertyNames = {
 
   // ESNext
 
+  // https://github.com/tc39/proposal-source-phase-imports?tab=readme-ov-file#js-module-source
+  ModuleSource: 'ModuleSource',
+
   lockdown: 'lockdown',
   harden: 'harden',
+
   HandledPromise: 'HandledPromise', // TODO: Until Promise.delegate (see below).
 };
 
@@ -1505,6 +1509,32 @@ export const permitted = {
     resolve: fn,
   },
 
+  // https://github.com/tc39/proposal-source-phase-imports?tab=readme-ov-file#js-module-source
+
+  ModuleSource: {
+    '[[Proto]]': '%AbstractModuleSource%',
+    prototype: '%ModuleSourcePrototype%',
+  },
+
+  '%ModuleSourcePrototype%': {
+    '[[Proto]]': '%AbstractModuleSourcePrototype%',
+    constructor: 'ModuleSource',
+    '@@toStringTag': 'string',
+    // https://github.com/tc39/proposal-compartments
+    bindings: getter,
+    needsImport: getter,
+    needsImportMeta: getter,
+  },
+
+  '%AbstractModuleSource%': {
+    '[[Proto]]': '%FunctionPrototype%',
+    prototype: '%AbstractModuleSourcePrototype%',
+  },
+
+  '%AbstractModuleSourcePrototype%': {
+    constructor: '%AbstractModuleSource%',
+  },
+
   Promise: {
     // Properties of the Promise Constructor
     '[[Proto]]': '%FunctionPrototype%',
diff --git a/packages/ses/src/tame-module-source.js b/packages/ses/src/tame-module-source.js
new file mode 100644
index 0000000000..6ceb3f9678
--- /dev/null
+++ b/packages/ses/src/tame-module-source.js
@@ -0,0 +1,51 @@
+import {
+  functionPrototype,
+  getPrototypeOf,
+  globalThis,
+  objectPrototype,
+  setPrototypeOf,
+} from './commons.js';
+
+export const tameModuleSource = () => {
+  const newIntrinsics = {};
+
+  const ModuleSource = globalThis.ModuleSource;
+  if (ModuleSource !== undefined) {
+    newIntrinsics.ModuleSource = ModuleSource;
+
+    // We introduce ModuleSource.[[Proto]] === AbstractModuleSource
+    // and ModuleSource.prototype.[[Proto]] === AbstractModuleSource.prototype
+    // if that layer is absent because the permitting system can more
+    // gracefully tolerate the absence of an expected prototype than the
+    // presence of an unexpected prototype,.
+    function AbstractModuleSource() {
+      // no-op safe to super()
+    }
+
+    const ModuleSourceProto = getPrototypeOf(ModuleSource);
+    if (ModuleSourceProto === functionPrototype) {
+      setPrototypeOf(ModuleSource, AbstractModuleSource);
+      newIntrinsics['%AbstractModuleSource%'] = AbstractModuleSource;
+      newIntrinsics['%AbstractModuleSourcePrototype%'] =
+        AbstractModuleSource.prototype;
+    } else {
+      newIntrinsics['%AbstractModuleSource%'] = ModuleSourceProto;
+      newIntrinsics['%AbstractModuleSourcePrototype%'] =
+        ModuleSourceProto.prototype;
+    }
+
+    const ModuleSourcePrototype = ModuleSource.prototype;
+    if (ModuleSourcePrototype !== undefined) {
+      newIntrinsics['%ModuleSourcePrototype%'] = ModuleSourcePrototype;
+
+      // ModuleSource.prototype.__proto__ should be the
+      // AbstractModuleSource.prototype.
+      const ModuleSourcePrototypeProto = getPrototypeOf(ModuleSourcePrototype);
+      if (ModuleSourcePrototypeProto === objectPrototype) {
+        setPrototypeOf(ModuleSource.prototype, AbstractModuleSource.prototype);
+      }
+    }
+  }
+
+  return newIntrinsics;
+};
diff --git a/packages/ses/test/module-source.test.js b/packages/ses/test/module-source.test.js
index 9d48d96391..f2385ae9e6 100644
--- a/packages/ses/test/module-source.test.js
+++ b/packages/ses/test/module-source.test.js
@@ -6,6 +6,19 @@ import '@endo/module-source/shim.js';
 
 lockdown();
 
+test('module source property/prototype graph and hardening', t => {
+  const AbstractModuleSource = Object.getPrototypeOf(ModuleSource);
+  t.is(
+    Object.getPrototypeOf(ModuleSource.prototype),
+    AbstractModuleSource.prototype,
+  );
+
+  t.truthy(Object.isFrozen(ModuleSource));
+  t.truthy(Object.isFrozen(AbstractModuleSource));
+  t.truthy(Object.isFrozen(ModuleSource.prototype));
+  t.truthy(Object.isFrozen(AbstractModuleSource.prototype));
+});
+
 test('module source constructor', t => {
   const msr = new ModuleSource(`
     import foo from 'import-default-export-from-me.js';
@@ -44,3 +57,7 @@ test('module source constructor', t => {
     'ModuleSource imports should be frozen',
   );
 });
+
+test('ModuleSource is a shared intrinsic', t => {
+  t.truthy(ModuleSource === new Compartment().globalThis.ModuleSource);
+});