diff --git a/.nx-cache-buster b/.nx-cache-buster
index 13adbbd1..692d5c67 100644
--- a/.nx-cache-buster
+++ b/.nx-cache-buster
@@ -1 +1 @@
-2024-03-23T18:18:45-07:00
+2024-06-01T20:52:18-07:00
diff --git a/jest.config.ts b/jest.config.ts
index e994f1a5..7ef9f20a 100644
--- a/jest.config.ts
+++ b/jest.config.ts
@@ -25,6 +25,7 @@ const commonProjectConfig: Partial<Config.ProjectConfig> = {
   setupFilesAfterEnv: ['./jest.d/setup-files-after-env/faker.ts'],
   testEnvironment: 'node',
   testPathIgnorePatterns: ['/dist/', '/node_modules/'],
+  transformIgnorePatterns: ['.*\\.mjs'],
 };
 
 const CI = !!process.env.CI;
@@ -51,7 +52,7 @@ const config: Config.GlobalConfig = {
           (packagePath) => !packagePath.split(path.sep).includes('examples')
         )
         .flatMap((packagePath) => [
-          `<rootDir>/${packagePath}/**/?(*.)+(test).[tj]s?(x)`,
+          `<rootDir>/${packagePath}/**/?(*.)+(test).?(m)[tj]s?(x)`,
         ]),
     },
     // @ts-expect-error - types seem wrong
diff --git a/package.json b/package.json
index 9f146bb4..3a3fae2c 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
     "lint:types": "bash -c \"tsc --build $TSC_OPTIONS\"",
     "postinstall": "patch-package",
     "prepare": "husky install",
-    "test": "TZ=UTC jest"
+    "test": "TZ=UTC node --experimental-vm-modules node_modules/jest/bin/jest.js"
   },
   "devDependencies": {
     "@aws-sdk/client-cloudformation": "3.188.0",
diff --git a/packages/@clc/nx/executors/package-json/executor.ts b/packages/@clc/nx/executors/package-json/executor.ts
index 3c699d7d..12054766 100644
--- a/packages/@clc/nx/executors/package-json/executor.ts
+++ b/packages/@clc/nx/executors/package-json/executor.ts
@@ -11,7 +11,7 @@ import {extractProjectName, extractProjectRoot, writePackageJson} from '../..';
 import type {PackageJsonExecutor} from './schema';
 
 const runExecutor: Executor<PackageJsonExecutor> = async (
-  {type = 'package'},
+  {mjs = false, mts = false, type = 'package'},
   context
 ) => {
   const root = extractProjectRoot(context);
@@ -21,7 +21,7 @@ const runExecutor: Executor<PackageJsonExecutor> = async (
   if (type === 'example') {
     await configExample(pkg, context);
   } else {
-    await config(pkg, type, context);
+    await config(pkg, mjs, mts, type, context);
   }
 
   await writePackageJson(packageJsonPath, pkg);
@@ -43,7 +43,9 @@ async function configExample(
 
 async function config(
   pkg: JSONSchemaForNPMPackageJsonFiles,
-  type: 'cli' | 'package',
+  mjs: boolean,
+  mts: boolean,
+  type: 'cli' | 'package' | 'esm',
   context: ExecutorContext
 ) {
   const packageName = extractProjectName(context);
@@ -63,12 +65,12 @@ async function config(
       // `types` should [always come first](https://nodejs.org/api/packages.html#community-conditions-definitions)
       import: {
         types: './dist/types/index.d.mts',
-        carpentry: './src/index.ts',
-        default: './dist/esm/index.mjs',
+        ...(mjs ? {} : {carpentry: mts ? './src/index.mts' : './src/index.ts'}),
+        default: mjs ? './src/index.mjs' : './dist/esm/index.mjs',
       },
       require: {
         types: './dist/cjs-types/index.d.ts',
-        carpentry: './src/index.ts',
+        ...(mjs ? {} : {carpentry: mts ? './src/index.mts' : './src/index.ts'}),
         default: './dist/cjs/index.cjs',
       },
       /* eslint-enable sort-keys */
diff --git a/packages/@clc/nx/executors/package-json/schema.d.ts b/packages/@clc/nx/executors/package-json/schema.d.ts
index b05403fa..6998be3e 100644
--- a/packages/@clc/nx/executors/package-json/schema.d.ts
+++ b/packages/@clc/nx/executors/package-json/schema.d.ts
@@ -6,5 +6,7 @@
  */
 
 export interface PackageJsonExecutor {
+  mjs?: boolean;
+  mts?: boolean;
   type?: 'cli' | 'example' | 'package';
 }
diff --git a/packages/@clc/nx/executors/package-json/schema.json b/packages/@clc/nx/executors/package-json/schema.json
index 10e88444..9c718a40 100644
--- a/packages/@clc/nx/executors/package-json/schema.json
+++ b/packages/@clc/nx/executors/package-json/schema.json
@@ -5,6 +5,14 @@
   "description": "",
   "type": "object",
   "properties": {
+    "mjs": {
+      "type": "boolean",
+      "default": false
+    },
+    "mts": {
+      "type": "boolean",
+      "default": false
+    },
     "type": {
       "enum": ["cli", "example", "package"],
       "type": "string",
diff --git a/packages/@clc/nx/src/create-nodes.ts b/packages/@clc/nx/src/create-nodes.ts
index 85fc88fa..b73de6db 100644
--- a/packages/@clc/nx/src/create-nodes.ts
+++ b/packages/@clc/nx/src/create-nodes.ts
@@ -20,6 +20,9 @@ export const createNodes: CreateNodes = [
       return {};
     }
 
+    const mjs = existsSync(path.resolve(projectRoot, 'src/index.mjs'));
+    const mts = existsSync(path.resolve(projectRoot, 'src/index.mts'));
+
     let targets: Record<string, TargetConfiguration> = {};
     // Set up the basic phases of the build process
 
@@ -88,25 +91,30 @@ export const createNodes: CreateNodes = [
         dependsOn: ['codegen'],
         executor: '@clc/nx:esbuild',
         options: {
-          entryPoints: ['{projectRoot}/src/**/*.[jt]s?(x)', '!**/*.test.*'],
+          entryPoints: ['{projectRoot}/src/**/*.?(m)[jt]s?(x)', '!**/*.test.*'],
           format: 'cjs',
           outDir: '{projectRoot}/dist/cjs',
         },
         outputs: ['{projectRoot}/dist/cjs'],
       });
 
-      addTarget(targets, 'build', 'esm', {
-        cache: true,
-        dependsOn: ['codegen'],
-        executor: '@clc/nx:esbuild',
-        inputs: ['{projectRoot}/src/**/*'],
-        options: {
-          entryPoints: ['{projectRoot}/src/**/*.[jt]s?(x)', '!**/*.test.*'],
-          format: 'esm',
-          outDir: '{projectRoot}/dist/esm',
-        },
-        outputs: ['{projectRoot}/dist/esm'],
-      });
+      if (!mjs) {
+        addTarget(targets, 'build', 'esm', {
+          cache: true,
+          dependsOn: ['codegen'],
+          executor: '@clc/nx:esbuild',
+          inputs: ['{projectRoot}/src/**/*'],
+          options: {
+            entryPoints: [
+              '{projectRoot}/src/**/*.?(m)[jt]s?(x)',
+              '!**/*.test.*',
+            ],
+            format: 'esm',
+            outDir: '{projectRoot}/dist/esm',
+          },
+          outputs: ['{projectRoot}/dist/esm'],
+        });
+      }
 
       addTarget(targets, 'build', 'types', {
         cache: true,
@@ -144,7 +152,7 @@ export const createNodes: CreateNodes = [
       cache: true,
       executor: '@clc/nx:package-json',
       inputs: ['{workspaceRoot}/package.json'],
-      options: {type},
+      options: {mjs, mts, type},
       outputs: ['{projectRoot}/package.json'],
     });
 
@@ -223,6 +231,7 @@ export const createNodes: CreateNodes = [
     if (projectName.split('/').pop()?.startsWith('tool-')) {
       addTarget(targets, 'codegen', 'tool', {
         cache: true,
+        dependsOn: ['^build'],
         executor: '@code-like-a-carpenter/tool-tool:tool',
         inputs: ['{projectRoot}/tools/*.json'],
         options: {
diff --git a/packages/@code-like-a-carpenter/assert/package.json b/packages/@code-like-a-carpenter/assert/package.json
index 412ed0c5..089defe5 100644
--- a/packages/@code-like-a-carpenter/assert/package.json
+++ b/packages/@code-like-a-carpenter/assert/package.json
@@ -10,12 +10,10 @@
     ".": {
       "import": {
         "types": "./dist/types/index.d.mts",
-        "carpentry": "./src/index.ts",
-        "default": "./dist/esm/index.mjs"
+        "default": "./src/index.mjs"
       },
       "require": {
         "types": "./dist/cjs-types/index.d.ts",
-        "carpentry": "./src/index.ts",
         "default": "./dist/cjs/index.cjs"
       }
     },
diff --git a/packages/@code-like-a-carpenter/assert/src/assert.ts b/packages/@code-like-a-carpenter/assert/src/assert.mjs
similarity index 82%
rename from packages/@code-like-a-carpenter/assert/src/assert.ts
rename to packages/@code-like-a-carpenter/assert/src/assert.mjs
index fccf6395..f04ede91 100644
--- a/packages/@code-like-a-carpenter/assert/src/assert.ts
+++ b/packages/@code-like-a-carpenter/assert/src/assert.mjs
@@ -2,12 +2,17 @@
 // eslint-disable-next-line no-restricted-imports
 import nodeAssert, {AssertionError} from 'assert';
 
-type Provider = () => string | Error;
+/**
+ * @callback Provider
+ * @returns {string | Error}
+ */
 
-export function assert(
-  value: unknown,
-  message: string | Error | Provider
-): asserts value {
+/**
+ * @param value {unknown}
+ * @param message {string | Error | Provider}
+ * @returns {asserts value}
+ */
+export function assert(value, message) {
   if (typeof message === 'string' || message instanceof Error) {
     nodeAssert.ok(value, message);
   } else {
diff --git a/packages/@code-like-a-carpenter/assert/src/assert.test.ts b/packages/@code-like-a-carpenter/assert/src/assert.test.mjs
similarity index 80%
rename from packages/@code-like-a-carpenter/assert/src/assert.test.ts
rename to packages/@code-like-a-carpenter/assert/src/assert.test.mjs
index aa3f6717..92d54c17 100644
--- a/packages/@code-like-a-carpenter/assert/src/assert.test.ts
+++ b/packages/@code-like-a-carpenter/assert/src/assert.test.mjs
@@ -1,11 +1,11 @@
 import {AssertionError} from 'assert';
 
-import {assert} from './assert';
+import {assert} from './assert.mjs';
 
 describe('assert', () => {
   it('throws a string error', () => {
     const fn = () => assert(false, 'error');
-    expect(fn).toThrowError(AssertionError);
+    expect(fn).toThrow(AssertionError);
     expect(fn).toThrowErrorMatchingInlineSnapshot(`"error"`);
   });
 
@@ -13,19 +13,19 @@ describe('assert', () => {
   // say it does.
   it.skip('throws a custom error', () => {
     const fn = () => assert(false, new TypeError('error'));
-    expect(fn).toThrowError(TypeError);
+    expect(fn).toThrow(TypeError);
     expect(fn).toThrowErrorMatchingInlineSnapshot();
   });
 
   it('throws a provided string error', () => {
     const fn = () => assert(false, () => 'error');
-    expect(fn).toThrowError(AssertionError);
+    expect(fn).toThrow(AssertionError);
     expect(fn).toThrowErrorMatchingInlineSnapshot(`"error"`);
   });
 
   it('throws a provided custom error', () => {
     const fn = () => assert(false, () => new TypeError('error'));
-    expect(fn).toThrowError(TypeError);
+    expect(fn).toThrow(TypeError);
     expect(fn).toThrowErrorMatchingInlineSnapshot(`"error"`);
   });
 });
diff --git a/packages/@code-like-a-carpenter/assert/src/index.mjs b/packages/@code-like-a-carpenter/assert/src/index.mjs
new file mode 100644
index 00000000..d981f4c4
--- /dev/null
+++ b/packages/@code-like-a-carpenter/assert/src/index.mjs
@@ -0,0 +1 @@
+export * from './assert.mjs';
diff --git a/packages/@code-like-a-carpenter/assert/src/index.ts b/packages/@code-like-a-carpenter/assert/src/index.ts
deleted file mode 100644
index 336b0ab1..00000000
--- a/packages/@code-like-a-carpenter/assert/src/index.ts
+++ /dev/null
@@ -1 +0,0 @@
-export * from './assert';
diff --git a/packages/@code-like-a-carpenter/env/package.json b/packages/@code-like-a-carpenter/env/package.json
index f05e6837..1b7606a4 100644
--- a/packages/@code-like-a-carpenter/env/package.json
+++ b/packages/@code-like-a-carpenter/env/package.json
@@ -6,12 +6,12 @@
     ".": {
       "import": {
         "types": "./dist/types/index.d.mts",
-        "carpentry": "./src/index.ts",
+        "carpentry": "./src/index.mts",
         "default": "./dist/esm/index.mjs"
       },
       "require": {
         "types": "./dist/cjs-types/index.d.ts",
-        "carpentry": "./src/index.ts",
+        "carpentry": "./src/index.mts",
         "default": "./dist/cjs/index.cjs"
       }
     },
diff --git a/packages/@code-like-a-carpenter/env/src/env.ts b/packages/@code-like-a-carpenter/env/src/env.mts
similarity index 77%
rename from packages/@code-like-a-carpenter/env/src/env.ts
rename to packages/@code-like-a-carpenter/env/src/env.mts
index c2bfd672..e1386c8d 100644
--- a/packages/@code-like-a-carpenter/env/src/env.ts
+++ b/packages/@code-like-a-carpenter/env/src/env.mts
@@ -1,5 +1,5 @@
-import {EnvironmentError} from './errors/environment-error';
-import {TypeNarrowingError} from './errors/type-narrowing-error';
+import {EnvironmentError} from './errors/environment-error.mts';
+import {TypeNarrowingError} from './errors/type-narrowing-error.mts';
 
 /**
  * Returns the value of the environment variable with the given key, using
diff --git a/packages/@code-like-a-carpenter/env/src/errors/environment-error.ts b/packages/@code-like-a-carpenter/env/src/errors/environment-error.mts
similarity index 100%
rename from packages/@code-like-a-carpenter/env/src/errors/environment-error.ts
rename to packages/@code-like-a-carpenter/env/src/errors/environment-error.mts
diff --git a/packages/@code-like-a-carpenter/env/src/errors/type-narrowing-error.ts b/packages/@code-like-a-carpenter/env/src/errors/type-narrowing-error.mts
similarity index 100%
rename from packages/@code-like-a-carpenter/env/src/errors/type-narrowing-error.ts
rename to packages/@code-like-a-carpenter/env/src/errors/type-narrowing-error.mts
diff --git a/packages/@code-like-a-carpenter/env/src/index.mts b/packages/@code-like-a-carpenter/env/src/index.mts
new file mode 100644
index 00000000..ea70bef8
--- /dev/null
+++ b/packages/@code-like-a-carpenter/env/src/index.mts
@@ -0,0 +1,3 @@
+export * from './env.mts';
+export * from './errors/environment-error.mts';
+export * from './errors/type-narrowing-error.mts';
diff --git a/packages/@code-like-a-carpenter/env/src/index.ts b/packages/@code-like-a-carpenter/env/src/index.ts
deleted file mode 100644
index 4d5e3945..00000000
--- a/packages/@code-like-a-carpenter/env/src/index.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-export * from './env';
-export * from './errors/environment-error';
-export * from './errors/type-narrowing-error';
diff --git a/packages/@code-like-a-carpenter/tool-deps/src/deps.ts b/packages/@code-like-a-carpenter/tool-deps/src/deps.ts
index 2fbb6b15..d005a6f7 100644
--- a/packages/@code-like-a-carpenter/tool-deps/src/deps.ts
+++ b/packages/@code-like-a-carpenter/tool-deps/src/deps.ts
@@ -6,7 +6,7 @@ import {minimatch} from 'minimatch';
 
 import {findLocalPackages} from '@code-like-a-carpenter/tooling-common';
 
-import type {DepsExecutor} from './__generated__/deps-types.ts';
+import type {DepsExecutor} from './__generated__/deps-types';
 import {load} from './config';
 import {runDepcheck} from './depcheck';
 
diff --git a/packages/@code-like-a-carpenter/tool-foundation/src/foundation.ts b/packages/@code-like-a-carpenter/tool-foundation/src/foundation.ts
index 981aa978..88f72b6a 100644
--- a/packages/@code-like-a-carpenter/tool-foundation/src/foundation.ts
+++ b/packages/@code-like-a-carpenter/tool-foundation/src/foundation.ts
@@ -1,6 +1,6 @@
 import {assert} from '@code-like-a-carpenter/assert';
 
-import type {Foundation} from './__generated__/foundation-types.ts';
+import type {Foundation} from './__generated__/foundation-types';
 import {generateCode} from './lib';
 
 export async function handler({
diff --git a/packages/@code-like-a-carpenter/tool-inliner/src/inliner.ts b/packages/@code-like-a-carpenter/tool-inliner/src/inliner.ts
index 2e505d02..d4307533 100644
--- a/packages/@code-like-a-carpenter/tool-inliner/src/inliner.ts
+++ b/packages/@code-like-a-carpenter/tool-inliner/src/inliner.ts
@@ -7,7 +7,7 @@ import * as t from '@babel/types';
 
 import {assert} from '@code-like-a-carpenter/assert';
 
-import type {InlinerExecutor} from './__generated__/inliner-types.ts';
+import type {InlinerExecutor} from './__generated__/inliner-types';
 
 export async function handler(args: InlinerExecutor): Promise<void> {
   const {sourceFile, targetFile, exportName} = args;
diff --git a/packages/@code-like-a-carpenter/tool-json-schema/src/json-schema.ts b/packages/@code-like-a-carpenter/tool-json-schema/src/json-schema.ts
index e4919355..40b325e6 100644
--- a/packages/@code-like-a-carpenter/tool-json-schema/src/json-schema.ts
+++ b/packages/@code-like-a-carpenter/tool-json-schema/src/json-schema.ts
@@ -4,7 +4,7 @@ import path from 'node:path';
 
 import {glob} from 'glob';
 
-import type {JsonSchemaTool} from './__generated__/json-schema-types.ts';
+import type {JsonSchemaTool} from './__generated__/json-schema-types';
 import {jsonSchemaToTypescript} from './json-schema-helpers';
 
 export async function handler({
diff --git a/packages/@code-like-a-carpenter/tool-stack/src/list.ts b/packages/@code-like-a-carpenter/tool-stack/src/list.ts
index 79174fc4..d00f9bb5 100644
--- a/packages/@code-like-a-carpenter/tool-stack/src/list.ts
+++ b/packages/@code-like-a-carpenter/tool-stack/src/list.ts
@@ -8,7 +8,7 @@ import {
   readPackageJson,
 } from '@code-like-a-carpenter/tooling-common';
 
-import type {StackListSchema} from './__generated__/list-types.ts';
+import type {StackListSchema} from './__generated__/list-types';
 
 export async function handler(args: StackListSchema): Promise<void> {
   const files =
diff --git a/packages/@code-like-a-carpenter/tool-stack/src/name.ts b/packages/@code-like-a-carpenter/tool-stack/src/name.ts
index 569bbd4d..2ea2756a 100644
--- a/packages/@code-like-a-carpenter/tool-stack/src/name.ts
+++ b/packages/@code-like-a-carpenter/tool-stack/src/name.ts
@@ -1,7 +1,7 @@
 import {assert, fail} from '@code-like-a-carpenter/assert';
 import {getStackName} from '@code-like-a-carpenter/tooling-common';
 
-import type {StackNameSchema} from './__generated__/name-types.ts';
+import type {StackNameSchema} from './__generated__/name-types';
 
 export async function handler(args: StackNameSchema): Promise<void> {
   if ('projectName' in args) {
diff --git a/packages/@code-like-a-carpenter/tool-stack/src/proxy.ts b/packages/@code-like-a-carpenter/tool-stack/src/proxy.ts
index 14e75603..9a786db6 100644
--- a/packages/@code-like-a-carpenter/tool-stack/src/proxy.ts
+++ b/packages/@code-like-a-carpenter/tool-stack/src/proxy.ts
@@ -7,7 +7,7 @@ import vhost from 'vhost';
 import {assert} from '@code-like-a-carpenter/assert';
 import {findLocalPackages} from '@code-like-a-carpenter/tooling-common';
 
-import type {StackProxySchema} from './__generated__/proxy-types.ts';
+import type {StackProxySchema} from './__generated__/proxy-types';
 import {findEndpoints, findStacks} from './stacks';
 
 // eslint-disable-next-line complexity
diff --git a/tsconfig.base.json b/tsconfig.base.json
index 7309859b..7923b58e 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -1,5 +1,6 @@
 {
   "compilerOptions": {
+    "allowImportingTsExtensions": true,
     "allowJs": true,
     "checkJs": true,
     "declaration": true,
@@ -8,7 +9,7 @@
     "jsx": "react",
     "lib": ["dom", "es2022"],
     "module": "es2022",
-    "moduleResolution": "node",
+    "moduleResolution": "Node",
     "resolveJsonModule": true,
     "strict": true,
     "target": "es2022",
diff --git a/tsconfig.json b/tsconfig.json
index 3c62ebb8..0d55bf6c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -4,20 +4,29 @@
   },
   "extends": "./tsconfig.base.json",
   "include": [
-    "*.ts",
-    "*.tsx",
     "*.js",
     "*.jsx",
+    "*.mjs",
+    "*.mts",
+    "*.ts",
+    "*.tsx",
     "examples/*/executors/**/*.js",
+    "examples/*/executors/**/*.mjs",
+    "examples/*/executors/**/*.mts",
     "examples/*/executors/**/*.ts",
     "examples/*/src/**/*.js",
     "examples/*/src/**/*.jsx",
+    "examples/*/src/**/*.mjs",
+    "examples/*/src/**/*.mts",
     "examples/*/src/**/*.ts",
     "examples/*/src/**/*.tsx",
     "packages/*/*/src/**/*.js",
     "packages/*/*/src/**/*.jsx",
+    "packages/*/*/src/**/*.mjs",
+    "packages/*/*/src/**/*.mts",
     "packages/*/*/src/**/*.ts",
     "packages/*/*/src/**/*.tsx",
+    "types/**/*.d.mts",
     "types/**/*.d.ts"
   ],
   "references": [