diff --git a/.github/workflows/smoke-codex.md b/.github/workflows/smoke-codex.md
index 641d109b..3573cdf7 100644
--- a/.github/workflows/smoke-codex.md
+++ b/.github/workflows/smoke-codex.md
@@ -72,6 +72,8 @@ post-steps:
       echo "Safe output validation passed"
 ---
 
+> **⚡ EXECUTE NOW:** Run all steps 1–8 below and call `add_comment` on this pull request with results. This is a mandatory smoke test execution—not documentation to read.
+
 # Smoke Test: Codex Engine Validation
 
 **IMPORTANT: Keep all outputs extremely short and concise. Use single-line responses where possible. No verbose explanations.**
diff --git a/containers/api-proxy/server.js b/containers/api-proxy/server.js
index 9c6acc4f..4589becb 100644
--- a/containers/api-proxy/server.js
+++ b/containers/api-proxy/server.js
@@ -60,6 +60,14 @@ function deriveCopilotApiTarget() {
     try {
       const hostname = new URL(serverUrl).hostname;
       if (hostname !== 'github.com') {
+        // For GitHub Enterprise Cloud with data residency (*.ghe.com),
+        // derive the API endpoint as api.SUBDOMAIN.ghe.com
+        // Example: mycompany.ghe.com -> api.mycompany.ghe.com
+        if (hostname.endsWith('.ghe.com')) {
+          const subdomain = hostname.replace('.ghe.com', '');
+          return `api.${subdomain}.ghe.com`;
+        }
+        // For other enterprise hosts (GHES), use the generic enterprise endpoint
         return 'api.enterprise.githubcopilot.com';
       }
     } catch {
@@ -387,6 +395,13 @@ function handleManagementEndpoint(req, res) {
   return false;
 }
 
+// Export for testing
+module.exports = {
+  deriveCopilotApiTarget,
+};
+
+// Only start servers if this file is run directly (not required for tests)
+if (require.main === module) {
 // Health port is always 10000 — this is what Docker healthcheck hits
 const HEALTH_PORT = 10000;
 
@@ -506,3 +521,5 @@ process.on('SIGINT', () => {
   logRequest('info', 'shutdown', { message: 'Received SIGINT, shutting down gracefully' });
   process.exit(0);
 });
+
+} // End of if (require.main === module)
diff --git a/containers/api-proxy/server.test.js b/containers/api-proxy/server.test.js
new file mode 100644
index 00000000..a38ee2e6
--- /dev/null
+++ b/containers/api-proxy/server.test.js
@@ -0,0 +1,95 @@
+/**
+ * Tests for API Proxy Server functions
+ */
+
+const { deriveCopilotApiTarget } = require('./server');
+
+describe('deriveCopilotApiTarget', () => {
+  let originalEnv;
+
+  beforeEach(() => {
+    // Save original environment
+    originalEnv = { ...process.env };
+  });
+
+  afterEach(() => {
+    // Restore original environment
+    process.env = originalEnv;
+  });
+
+  test('should return default api.githubcopilot.com when no env vars set', () => {
+    delete process.env.COPILOT_API_TARGET;
+    delete process.env.GITHUB_SERVER_URL;
+
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.githubcopilot.com');
+  });
+
+  test('should use COPILOT_API_TARGET when explicitly set', () => {
+    process.env.COPILOT_API_TARGET = 'custom.api.example.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('custom.api.example.com');
+  });
+
+  test('should prioritize COPILOT_API_TARGET over GITHUB_SERVER_URL', () => {
+    process.env.COPILOT_API_TARGET = 'custom.api.example.com';
+    process.env.GITHUB_SERVER_URL = 'https://mycompany.ghe.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('custom.api.example.com');
+  });
+
+  test('should return api.githubcopilot.com for github.com', () => {
+    process.env.GITHUB_SERVER_URL = 'https://github.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.githubcopilot.com');
+  });
+
+  test('should derive api.SUBDOMAIN.ghe.com for *.ghe.com domains', () => {
+    process.env.GITHUB_SERVER_URL = 'https://mycompany.ghe.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.mycompany.ghe.com');
+  });
+
+  test('should derive api.SUBDOMAIN.ghe.com for different *.ghe.com subdomain', () => {
+    process.env.GITHUB_SERVER_URL = 'https://acme-corp.ghe.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.acme-corp.ghe.com');
+  });
+
+  test('should use api.enterprise.githubcopilot.com for GHES (non-.ghe.com enterprise)', () => {
+    process.env.GITHUB_SERVER_URL = 'https://github.enterprise.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.enterprise.githubcopilot.com');
+  });
+
+  test('should use api.enterprise.githubcopilot.com for custom GHES domain', () => {
+    process.env.GITHUB_SERVER_URL = 'https://git.mycompany.com';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.enterprise.githubcopilot.com');
+  });
+
+  test('should handle GITHUB_SERVER_URL without protocol gracefully', () => {
+    process.env.GITHUB_SERVER_URL = 'mycompany.ghe.com';
+    const target = deriveCopilotApiTarget();
+    // Invalid URL, should fall back to default
+    expect(target).toBe('api.githubcopilot.com');
+  });
+
+  test('should handle invalid GITHUB_SERVER_URL gracefully', () => {
+    process.env.GITHUB_SERVER_URL = 'not-a-valid-url';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.githubcopilot.com');
+  });
+
+  test('should handle GITHUB_SERVER_URL with port', () => {
+    process.env.GITHUB_SERVER_URL = 'https://mycompany.ghe.com:443';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.mycompany.ghe.com');
+  });
+
+  test('should handle GITHUB_SERVER_URL with path', () => {
+    process.env.GITHUB_SERVER_URL = 'https://mycompany.ghe.com/some/path';
+    const target = deriveCopilotApiTarget();
+    expect(target).toBe('api.mycompany.ghe.com');
+  });
+});
diff --git a/docs/api-proxy-sidecar.md b/docs/api-proxy-sidecar.md
index dc9b5c81..e0a092c6 100644
--- a/docs/api-proxy-sidecar.md
+++ b/docs/api-proxy-sidecar.md
@@ -101,6 +101,41 @@ sudo awf --enable-api-proxy \
   -- your-multi-llm-tool
 ```
 
+### GitHub Enterprise Cloud (*.ghe.com) configuration
+
+For GitHub Enterprise Cloud with data residency (e.g., `mycompany.ghe.com`), the API proxy automatically derives the correct Copilot API endpoint:
+
+```bash
+export COPILOT_GITHUB_TOKEN="your-token"
+export GITHUB_SERVER_URL="https://mycompany.ghe.com"
+
+sudo -E awf --enable-api-proxy \
+  --allow-domains '*.mycompany.ghe.com' \
+  -- npx @github/copilot --prompt "your prompt"
+```
+
+**How it works:**
+- The api-proxy reads `GITHUB_SERVER_URL` and extracts the subdomain
+- For `*.ghe.com` domains, it automatically routes to `api.SUBDOMAIN.ghe.com`
+- Example: `mycompany.ghe.com` → `api.mycompany.ghe.com`
+- For other enterprise hosts (GHES), it routes to `api.enterprise.githubcopilot.com`
+
+**Domain matching:**
+- `*.mycompany.ghe.com` matches all subdomains (e.g., `api.mycompany.ghe.com`, `github.mycompany.ghe.com`)
+- Add additional domains only if your workflow needs to access other services (e.g., `mycompany.ghe.com` for the base domain)
+
+**Important:** Use `sudo -E` to preserve the `GITHUB_SERVER_URL` environment variable when running awf.
+
+You can also explicitly set the Copilot API target:
+
+```bash
+export COPILOT_API_TARGET="api.mycompany.ghe.com"
+sudo -E awf --enable-api-proxy \
+  --copilot-api-target api.mycompany.ghe.com \
+  --allow-domains '*.mycompany.ghe.com' \
+  -- npx @github/copilot --prompt "your prompt"
+```
+
 ## Environment variables
 
 AWF manages environment variables differently across the three containers (squid, api-proxy, agent) to ensure secure credential isolation.
@@ -123,6 +158,8 @@ The API proxy sidecar receives **real credentials** and routing configuration:
 | `OPENAI_API_KEY` | Real API key | `--enable-api-proxy` and env set | OpenAI API key (injected into requests) |
 | `ANTHROPIC_API_KEY` | Real API key | `--enable-api-proxy` and env set | Anthropic API key (injected into requests) |
 | `COPILOT_GITHUB_TOKEN` | Real token | `--enable-api-proxy` and env set | GitHub Copilot token (injected into requests) |
+| `COPILOT_API_TARGET` | Target hostname | `--copilot-api-target` flag or host env `COPILOT_API_TARGET` | Override Copilot API endpoint (default: auto-derived) |
+| `GITHUB_SERVER_URL` | GitHub server URL | Passed from host env | Auto-derives Copilot API endpoint for enterprise (*.ghe.com → api.SUBDOMAIN.ghe.com) |
 | `HTTP_PROXY` | `http://172.30.0.10:3128` | Always | Routes through Squid for domain filtering |
 | `HTTPS_PROXY` | `http://172.30.0.10:3128` | Always | Routes through Squid for domain filtering |