Claude Code adds mods, small TypeScript functions that change how it works

TL;DR

• On 1 October Anthropic added mods to Claude Code 2.1.287: small TypeScript functions, shipped in plugins, that hook events like tool calls, permission requests and screen drawing.
• A mod can rewrite a prompt, block or retry a tool call, approve a permission request or replace a built-in feature such as /diff.
• No sandbox walls a mod off from your machine, so Anthropic says to install mods only from sources you trust.