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Debug browser bugs in Claude Code — from real evidence

Claude Code registers MCP servers with a single CLI command — this is the fastest setup of any tool. One line, and Claude can read every TraceBug export on your machine. Everything runs locally: the server is stdio-only, opens zero network connections, and reads report files from your disk. See the unedited transcript of Claude going from crash to root cause in five tool calls.

  1. 1

    Add the server

    Run this once, anywhere. The --scope user flag makes it available in every project; drop it to register for the current project only.

    Terminal
    claude mcp add tracebug --scope user -- npx -y tracebug mcp
  2. 2

    Capture a bug

    Use the TraceBug extension (or SDK) to capture a bug and click Export .html. The server auto-discovers exports in your Downloads and Desktop folders — no paths to configure. To pin a project folder instead, add --dir ./bug-reports to the command above.

  3. 3

    Ask Claude to investigate

    Start a Claude Code session and say: "List my bug reports and investigate the newest one." Claude calls list_bug_reports, pulls the evidence, and starts from the actual failing line. There's also a built-in prompt: /tracebug:debug_bug_report.

Verify it worked

Run `claude mcp list` — tracebug should appear with a ✓. In a session, ask "what MCP tools do you have?" and look for list_bug_reports.

Troubleshooting

claude mcp list shows tracebug as failed
The server needs Node 18+. Check node --version, then remove and re-add the server.
Claude says it has no bug-report tools
MCP servers load at session start — exit and start a new session after adding the server.
list_bug_reports returns nothing
The export has to exist first: capture a bug and Export .html, or pass --dir pointing at the folder that holds your exports.
No bug handy? Make one.
The live sandbox has intentional bugs — capture one, export it, and hand it to Claude Code.
Open the sandbox

Full MCP reference — all six tools, the report format, and the FAQ — lives at /docs/mcp. Other tools: Cursor · Windsurf.