New "External Browser Mode" that connects to an existing browser via Chrome DevTools Protocol (CDP) instead of launching Playwright's bundled Chromium#20
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mattheworiordan wants to merge 4 commits intoSawyerHood:mainfrom
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Add serveWithExternalBrowser() that connects to an existing browser via CDP instead of launching Playwright's Chromium. Key features: - Connect to any browser with CDP enabled (Chrome for Testing, Chrome Beta, etc.) - Auto-launch browser if not running (with BROWSER_PATH env var) - Browser stays open after server stops (user manages lifecycle) - No extension required - direct CDP connection New files: - src/external-browser.ts - Core implementation - scripts/start-external-browser.ts - Startup script Use case: Local development with visible browser automation where you want to inspect results after automation completes.
When multiple AI agents run browser automation tasks in parallel, they need separate HTTP API ports while potentially sharing the same browser instance. This adds automatic port allocation to avoid conflicts. Key changes: - Add port-manager.ts for dynamic port allocation (range 9222-9300) - Server tracking via ~/.dev-browser/active-servers.json - PORT=XXXX output for agent discovery - Config file support at ~/.dev-browser/config.json - Update both standalone and external browser modes Architecture: Agent 1 → server (port 9222) ┐ Agent 2 → server (port 9224) ├→ Shared Browser (CDP 9223) Agent 3 → server (port 9226) ┘ See docs/CONCURRENCY.md for design decisions and usage examples. Addresses concerns raised in PR SawyerHood#15 about single-point congestion.
When a dev-browser server crashes, its Chrome browser may still be running on the CDP port. This adds smart cleanup to detect and terminate orphaned browsers before launching new ones. Key changes: - Enhanced ServerInfo structure to track CDP port and mode - Added detectOrphanedBrowsers() to find browsers with no registered server - Added cleanupOrphanedBrowsers() to safely terminate orphans - Standalone mode now cleans orphans on startup (before launching browser) - External mode tracks CDP port but doesn't clean (browser is intentionally external) This restores crash recovery functionality that was previously in start-server.ts, but in a smarter way that respects multi-agent scenarios.
4 tasks
- Add ~/.dev-browser/config.json for browser configuration - Auto-detect Chrome for Testing on macOS/Linux/Windows - Add --standalone flag to force Playwright mode - Skip npm install when dependencies unchanged (hash check) - Rename port-manager.ts to config.ts with browser config - Let browser use default profile unless userDataDir explicitly set - Simplify SKILL.md documentation with single startup flow
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Motivation
I use Chrome for Testing for local development and wanted dev-browser to:
Currently I'm using a patched version that works, but I'd love to contribute this upstream so others can benefit.
Changes
src/external-browser.ts- NewserveWithExternalBrowser()function that:browserPathprovided)scripts/start-external-browser.ts- Startup script with env var configuration:BROWSER_PATH- Path to browser executableCDP_PORT- Browser's CDP port (default: 9223)USER_DATA_DIR- Persistent profile directorySKILL.md- Updated documentation with new modeUsage
Compatibility