add --executable-path

README.md

@@ -293,6 +293,7 @@ agent-browser snapshot -i -c -d 5         # Combine options
 | Option | Description |
 |--------|-------------|
 | `--session <name>` | Use isolated session (or `AGENT_BROWSER_SESSION` env) |
+| `--executable-path <path>` | Custom browser executable (or `AGENT_BROWSER_EXECUTABLE_PATH` env) |
 | `--json` | JSON output (for agents) |
 | `--full, -f` | Full page screenshot |
 | `--name, -n` | Locator name filter |
@@ -387,6 +388,39 @@ agent-browser open example.com --headed
 
 This opens a visible browser window instead of running headless.
 
+## Custom Browser Executable
+
+Use a custom browser executable instead of the bundled Chromium. This is useful for:
+- **Serverless deployment**: Use lightweight Chromium builds like `@sparticuz/chromium` (~50MB vs ~684MB)
+- **System browsers**: Use an existing Chrome/Chromium installation
+- **Custom builds**: Use modified browser builds
+
+### CLI Usage
+
+```bash
+# Via flag
+agent-browser --executable-path /path/to/chromium open example.com
+
+# Via environment variable
+AGENT_BROWSER_EXECUTABLE_PATH=/path/to/chromium agent-browser open example.com
+```
+
+### Serverless Example (Vercel/AWS Lambda)
+
+```typescript
+import chromium from '@sparticuz/chromium';
+import { BrowserManager } from 'agent-browser';
+
+export async function handler() {
+  const browser = new BrowserManager();
+  await browser.launch({
+    executablePath: await chromium.executablePath(),
+    headless: true,
+  });
+  // ... use browser
+}
+```
+
 ## Architecture
 
 agent-browser uses a client-daemon architecture: