Claude DevTools
Breakpoints for tool calls: stop before git push, see why the last call failed.
Illustration. Actual results depend on the mod, terminal and environment.
Install
/plugin marketplace add NMenzel/claude-devtools-mod
/plugin install devtools@claude-devtools-mod
/reload-pluginsRun these commands one at a time in a Claude Code session.
claude plugin marketplace add NMenzel/claude-devtools-mod
claude plugin install devtools@claude-devtools-modThen run /reload-plugins in your session, or start a new session.
Please install the Claude Code mod "Claude DevTools" (https://github.com/NMenzel/claude-devtools-mod). Before installing, read the Security and Requirements sections of its README and tell me what it reads and writes, which commands it runs, whether it uses the network, and which Claude Code version, OS and terminal it needs. If everything looks fine, run claude plugin marketplace add NMenzel/claude-devtools-mod and claude plugin install devtools@claude-devtools-mod, then remind me to run /reload-plugins in my session.Send this to Claude Code so it reads the author’s instructions before installing.
git clone https://github.com/NMenzel/claude-devtools-mod
cd claude-devtools-mod
claude --plugin-dir .Clone the repository and try it in a local session with --plugin-dir.
What it accesses
Based on the author’s documentation, checked when listed; use claude plugin validate to check for yourself.
Reads
YesReads tool calls, results, permission verdicts and settings permissions; Error Lens stats failed paths, never contents.
Writes files
YesWrites .claude-devtools/trace-*.json/.md on export; saves breakpoint rules in the plugin store.
Runs commands
NoneNetwork
NoneIntroduction
Claude DevTools is a Claude Code mod that debugs Claude's tool calls like a browser's DevTools.
- Breakpoints on tools, command patterns, path globs or failures (e.g.
/bp command git push). A match asks Continue, Step or Reject; Reject tells Claude to try another way. - Error Lens classifies a failure, marks what is confirmed, possible or unknown, and suggests fixes; repeats are grouped.
- A pane with a timeline and inspector (status, duration, agent, permission verdict), a "break on" gutter under tool rows and a bar above the prompt.
- Sanitized exports to
.claude-devtools/when you run/devtools-export.
It never approves a call; your permission rules still decide. It sees tool calls only, not hidden reasoning. The author states no network, no model calls and no processes. Mods need Claude Code 2.1.287+; built and tested on 2.1.294 (Windows 10).
Who it is for
- People who want Claude to stop before git push, npm publish and other risky commands
- People who want to know why a tool call keeps failing
Requirements
- Claude Code ≥ 2.1.287
- Built and tested on 2.1.294 (Windows 10); older builds are untested.
- Draws in the terminal and Desktop's Code tab; VS Code chat and claude -p get commands only.
- The pane docks at 144+ columns; hover controls need fullscreen terminal or Desktop.