diff --git a/package.json b/package.json
index fd29cee8..88fd7b91 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,9 @@
   "main": "src/index.js",
   "exports": {
     ".": {
-      "import": "./src/index.js"
+      "import": "./src/index.js",
+      "require": "./src/index.cjs",
+      "default": "./src/index.cjs"
     },
     "./cli": {
       "import": "./src/cli.js"
diff --git a/src/index.cjs b/src/index.cjs
new file mode 100644
index 00000000..811e449c
--- /dev/null
+++ b/src/index.cjs
@@ -0,0 +1,16 @@
+/**
+ * CJS compatibility wrapper — delegates to ESM via dynamic import().
+ *
+ * This wrapper always returns a Promise on every Node version, because
+ * import() is unconditionally async. You must always await the result:
+ *
+ *   const codegraph = await require('@optave/codegraph');
+ *
+ * // Named destructuring at require-time does NOT work — always await the full result first.
+ * // BAD:  const { buildGraph } = require('@optave/codegraph');  // buildGraph is undefined
+ * // GOOD: const { buildGraph } = await require('@optave/codegraph');
+ */
+// Note: if import() rejects (e.g. missing dependency), the rejected Promise is cached
+// by the CJS module system and every subsequent require() call will re-surface the same
+// rejection without re-attempting the load.
+module.exports = import('./index.js');
diff --git a/tests/unit/index-exports.test.js b/tests/unit/index-exports.test.js
index a5a912b7..ecd06bdb 100644
--- a/tests/unit/index-exports.test.js
+++ b/tests/unit/index-exports.test.js
@@ -1,6 +1,18 @@
+import { readFileSync } from 'node:fs';
+import { createRequire } from 'node:module';
+import { dirname, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
 import { describe, expect, it } from 'vitest';
 
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const pkg = JSON.parse(readFileSync(resolve(__dirname, '../../package.json'), 'utf8'));
+
 describe('index.js re-exports', () => {
+  it('package.json exports map points to CJS wrapper', () => {
+    expect(pkg.exports['.']).toBeDefined();
+    expect(pkg.exports['.'].require).toBe('./src/index.cjs');
+  });
+
   it('all re-exports resolve without errors', async () => {
     // Dynamic import validates that every re-exported module exists and
     // all named exports are resolvable. If any source file is missing,
@@ -9,4 +21,24 @@ describe('index.js re-exports', () => {
     expect(mod).toBeDefined();
     expect(typeof mod).toBe('object');
   });
+
+  it('CJS wrapper resolves to the same exports', async () => {
+    const require = createRequire(import.meta.url);
+    const cjs = await require('../../src/index.cjs');
+    const esm = await import('../../src/index.js');
+    // Every named ESM export should resolve to a real value, not undefined.
+    // CJS import() produces a separate module namespace so reference equality
+    // (toBe) is not possible, but we verify the export exists, is defined,
+    // and has the same type as its ESM counterpart.
+    for (const key of Object.keys(esm)) {
+      if (key === 'default') continue;
+      expect(cjs[key], `CJS export "${key}" is missing or undefined`).toBeDefined();
+      expect(typeof cjs[key]).toBe(typeof esm[key]);
+    }
+
+    // Symmetric check: CJS should not have extra keys beyond ESM exports.
+    const esmKeys = new Set(Object.keys(esm).filter((k) => k !== 'default'));
+    const cjsKeys = new Set(Object.keys(cjs).filter((k) => k !== 'default'));
+    expect(cjsKeys).toEqual(esmKeys);
+  });
 });