Anthropic Adds Mod Support to Claude Code
Mods are distributed as plugins and can be restricted by administrators on Team and Enterprise plans, where a built-in sec-default mod loads first to stop user mods from overriding permission denial rules.
Key Facts
- Anthropic released the mod feature for Claude Code on version 2.1.287 or later, with no configuration required.
- Claude Code mods are written in JavaScript or TypeScript, and users can ask Claude to write a mod from a plain-language description.
- Anthropic's sample mods include Blast Radius, Token Weather, and Replay Theater.
- Mods can be installed via the /plugin command and shared by publishing a GitHub repository as a marketplace.
- On Team and Enterprise plans, the sec-default mod loads first to prevent user-installed mods from overriding permission denial rules.
Reporting from 2 sources: GameBusiness.jp, GIGAZINE.
Anthropic released a mod feature for its AI coding tool Claude Code on Claude Code v2.1.287 or later, available in both the CLI version and the desktop app. Mods are small functions written in JavaScript or TypeScript that can intercept tool calls, prompt submissions, and screen rendering, then inspect, rewrite, or take over that content. They differ from the older hooks system because mods can stay resident in a session and keep state. Anthropic shipped three sample mods: Blast Radius lists affected files before a command such as rm -rf runs, Token Weather shows the remaining context window as weather, and Replay Theater plays back Claude's file operations with diffs. Users can ask Claude itself to write a mod in plain language, and the change applies without restarting the session. Because mods run with the same privileges as Claude Code and are not sandboxed, Anthropic says users should install only ones they trust.
Mods are bundled inside plugins, so administrators can control installation through the existing plugin management system on Team and Enterprise plans. In managed settings environments, a built-in mod called sec-default loads first and blocks user mods from overriding permission denial rules.
Some built-in Claude Code features are already implemented as mods. The /diff command for showing differences is one of them, and users can disable it or replace it. Anthropic says it plans to keep moving built-in features to mods, leaving a small core.
Two limits matter on the client side. Mods work in the CLI and in the Code tab of the desktop app. In the VS Code extension, the mod processing runs but screen rendering is not supported.
Mods can read and write files, read API keys placed in environment variables, and approve tool calls on their own, which is why Anthropic asks users to install only mods they trust. Intended uses include CI/CD status displays, confirmation prompts for commands that touch production environments, and audit logs.
A catalog of sample mods ships with the feature:
Synthesized by Yomimono from the 2 cited sources below, including Japanese-language reporting where cited, then editorially reviewed before publishing.
Sources
- GameBusiness.jp Claude Codeが拡張機能「mod」対応、UIや動作をカスタマイズ。Claude書かせて作成も
- GIGAZINE Claude Codeを自分好みにカスタムできるMod機能が登場