dmd

dmd - Cursor Debug Mode–style debugging for Claude Code

Brings Cursor's Debug Mode to Claude Code. A plugin that guides Claude through hypothesis-driven debugging — hypothesize, instrument, collect logs, verify — via /dmd:start.

Requirement: Bun

Quick start

git clone https://github.com/laiso/claude-code-dmd.git
cd claude-code-dmd/demo
claude --plugin-dir ..

Then run /dmd:start and tell Claude "the app has bugs." Claude takes it from there. See demo/README.md for the bug list and details.

To use with your own project: claude --plugin-dir /path/to/claude-code-dmd from your project root. Plugins docs

How it works

/dmd:start walks Claude through a structured loop:

1. Hypothesize — form 3–5 candidate explanations
2. Instrument — insert logging wrapped in #region agent log markers
3. Collect — run the app; logs append as NDJSON to .claude/debug-<session>.log
4. Verify — read the log, confirm or reject each hypothesis, fix, re-run

The dmd CLI manages sessions and log files under .claude/. For browser-side logging, dmd serve runs a small localhost HTTP ingest (default 127.0.0.1:8792) that accepts POSTs at /ingest and writes to the same log file.

{"message":"Repro: bulk discount stacks incorrectly","hypothesisId":"H1","timestamp":1712223334444}

Full CLI reference, environment variables, and ingest details: spec/dmd-cli-and-runtime.md

Limitations

• Experimental — not production-ready
• Localhost only — ingest binds to 127.0.0.1; do not expose publicly
• No auto-cleanup — logs persist until you run dmd remove or dmd remove-all

Development

bun install
bun run typecheck

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dmd = debug mode (unrelated to dlang/dmd) · spec · Plugins docs