Chrome Console Log Server

Capture browser console logs via the Chrome DevTools Protocol and expose them to an MCP client over SSE.

Useful for getting console log for extensions that run outside of the main browser window!

Install

npm install -g @onlyhumn/chrome-console-log-mcp-server

Or run without installing:

npx @onlyhumn/chrome-console-log-mcp-server --match "YOUR_URL_SUBSTRING"

From a clone:

npm install
node server.js --match "YOUR_URL_SUBSTRING"

Usage

1. Start the browser with remote debugging:

   /Applications/Brave\ Browser.app/Contents/MacOS/Brave\ Browser --remote-debugging-port=9222
   

2. Start the server (requires --match):

   npx @onlyhumn/chrome-console-log-mcp-server --match "YOUR_URL_SUBSTRING"
   

   Examples:

   npx @onlyhumn/chrome-console-log-mcp-server --match "localhost:3000"
   npx @onlyhumn/chrome-console-log-mcp-server --match "vlt-panel.html"
   

3. Configure your MCP client:

   • Type: sse
   • URL: http://localhost:8766/sse

4. Open or focus a page whose URL contains the match string. The server prints Attached to ... when it finds a match. Use the getConsoleLogs tool to read captured output.

Flags

Flag	Default	Meaning
--match	required	URL substring for CDP targets
--port	9222	CDP remote debugging port
--mcp-port	8766	HTTP port for MCP SSE
--log-dir	/tmp/chrome-console-logs	log directory
--log-max-bytes	10485760 (10 MB)	rotate threshold
--log-keep	5	rotated .gz files to keep
--scan-interval	2000	CDP target rescan interval (ms)

Logs

Console events are appended to /tmp/chrome-console-logs/current.jsonl. When the file exceeds the rotate threshold it is gzipped and pruned so only the newest --log-keep archives remain.

Releasing

Publishes run from GitHub Actions on v* tags. The tag must match package.json "version".

1. Ensure the npm org/user owns the @onlyhumn scope.

2. First publish only: from a machine logged into npm (npm login), run npm publish --access public once so the package exists, or create the package on npmjs.com if your account allows it.

3. On the package page → Trusted Publisher (values are case-sensitive; must match GitHub OIDC claims):

   • Repository: ONLYHUMN/chrome-console-log-mcp-server (not lowercase onlyhumn/...)
   • Workflow filename: publish.yml
   • Leave Environment blank (workflow does not set one)

4. Bump "version" in package.json, commit, push to master.

5. Tag and push:

   git tag v1.0.1
   git push origin v1.0.1
   

A Trusted Publishing failure often shows up as a misleading E404 from npm publish.

Troubleshooting

• Browser must be started with --remote-debugging-port=9222 (or the port you pass to --port)
• --match is required; without it the process exits immediately
• Confirm the server printed Attached to ... for your page
• MCP client URL should be http://localhost:8766/sse (or your --mcp-port)

License

MIT License