What is devtools?
devtools is a Claude Code mod by NMenzel that a debugger for Claude Code tool calls: breakpoints, pause/continue/reject/step, a timeline, an inspector, Error Lens failure diagnosis, a Permissions view of who refused each call and why,. It is listed under Interface and has 2 GitHub stars.
| Type | Claude code mod |
|---|---|
| Author | NMenzel |
| Repository | NMenzel/claude-devtools-mod |
| Popularity | 2 GitHub stars |
| Category | Interface |
| Security | Low risk (88/100) |
| Rank | #1,369 of 5,272 Claude Code mods; #535 in Interface |
| License | MIT |
| Last commit | 2026-10-12 |
| Hooks | 7 events |
| Sees | classic hooks, every tool call |
| Draws on | Pane, ToolUse, ToolGroup, AbovePrompt |
Is devtools safe to install?
devtools scores 88/100 on the MCPMods security check: Low risk. Things to review: writes files or config. It passed 7 of 8 checks.
Mod footprints come from claude plugin validate, which lists every event a mod hooks and every API call it makes without running it.
| Check | Result |
|---|---|
| No network access | Pass |
| Starts no processes | Pass |
| Writes files or config | Review |
| Doesn't read environment variables | Pass |
| Only sees the events it hooks | Pass |
| Doesn't drive Claude | Pass |
| Passes claude plugin validate | Pass |
| Has an open-source license | Pass |
API calls in its code
| Call | What it means |
|---|---|
$.clock.after | |
$.clock.now | |
$.command.register | |
$.fs.exists | reads files |
$.fs.stat | reads files |
$.fs.write | writes files |
$.session.cwd | |
$.session.id | |
$.session.messages | reads the transcript |
$.settings.read | reads settings |
$.state.get | |
$.state.set | |
$.store.get | keeps its own state |
$.store.set | keeps its own state |
$.tool.check | |
$.ui.ask | draws interface |
$.ui.log | draws interface |
$.ui.open | draws interface |
$.ui.resolve | draws interface |
$.ui.status | draws interface |
$.ui.toast | draws interface |
How do I install devtools?
- Check your Claude Code version. Mods need Claude Code 2.1.287 or later and are on by default.
claude --version
- Read its footprint. This lists every event it hooks and every API call it makes, without running it.
git clone https://github.com/NMenzel/claude-devtools-mod claude plugin validate ./claude-devtools-mod/.
- Install it. Run this in your terminal, then /reload-plugins in an open session.
claude plugin marketplace add NMenzel/claude-devtools-mod && claude plugin install devtools@claude-devtools-mod
Or ask Claude to set it up
Paste this into Claude Code and it installs devtools for you:
Install the "devtools" Claude Code mod from https://github.com/NMenzel/claude-devtools-mod. Run claude plugin validate on it first and show me what it can access before you enable it.