Anthropic launches mods for Claude Code: TypeScript plugins that change its behavior, interface and tool calls

2026-10-01★★★after cutoffproductAnthropicconfidence: high

On Oct 1, 2026 Anthropic opened Claude Code to "mods": JavaScript/TypeScript event handlers shipped inside plugins that run in Claude Code's own process and can watch, rewrite or take over tool calls, prompts, commands and parts of the interface (panes, the spinner, dialogs). Users can write one or ask Claude to build it. Mods are not sandboxed and run with the user's permissions; the launch post drew ~2.1M views.

Key facts

Announced by @ClaudeDevs on Oct 1, 2026: 'You can now mod Claude Code: change how it behaves, customize the UI, swap in your own features' (~2.1M views, ~14.8k likes by Oct 2)
A mod is a plugin whose hooks module registers handlers for events such as tool.call and ui.render; a handler can observe, rewrite or answer an event
Can draw panes and a band above the prompt, restyle built-in UI (tool-call rows, spinner, question dialog), hold or answer a tool call, send a request to a different model, add /commands that run without a Claude turn
Installed like any plugin (/plugin install name@marketplace); requires Claude Code v2.1.287+; on by default; works in the CLI and the Desktop app's Code tab (hooks also run in claude -p, the Agent SDK and the VS Code panel, without drawing)
Security: mods run with the user's permissions, are not sandboxed (a process a mod starts runs outside Bash sandboxing), can read secrets and can approve tool calls an 'ask' rule would prompt for; they cannot restyle the permission prompt
Some built-in features are now mods, e.g. /diff, AGENTS.md loading and telemetry; samples token-weather, blast-radius and replay-theater are in anthropics/claude-code-playground
Admins can restrict mods via managed settings (e.g. allowManagedModsOnly); users can disable them with --safe-mode or disableAllHooks

What happened

Claude Code already had settings hooks (shell commands run on events), skills and MCP servers, all working from outside the app. Mods run inside it, so a few lines of TypeScript can add a pane that charts context usage, stop a risky rm -rf behind a confirmation, or send a request to another model. Anthropic moved some of its own features onto the same system.

Why it matters

Coding agents are becoming platforms that users can reprogram. Mods can approve tool calls and read secrets, which widens the supply-chain risk of plugin marketplaces. The docs say plainly that a mod is code running with your permissions.

Changelog

2026-10-02: created

Videos (1)

Mods in Claude Code: change how Claude Code works

Claude · 2026-10-05 · official

Description by Gemini, which watched the video:

Summary
Anthropic developer advocate Lydia Hallie introduces and demonstrates "mods" for Claude Code, a new plugin-based extension system that lets developers alter how Claude Code functions internally. Mods are written in TypeScript and act as middleware running on Claude Code's internal event loop, enabling users to intercept tool calls, inject UI elements, customize prompts, and modify rendered output.

What is shown

Overview of Mods & Architecture: Code in register.tsx demonstrating event listeners (on('ui.render'), on('prompt.submit'), on('tool.call')) manipulating Claude Code runtime behavior [00:06].
Demonstrated Custom Mods:
- context-bar: A live visual bar above the prompt breaking down context window usage (system prompt, tools, MCP tools, agents, memory files, skills, free space of a 1M token window) [00:17].
- agents-panel: A sidebar listing all defined project agents (e.g., code-reviewer, docs-writer, perf-profiler) with single-click start buttons [00:26].
- hide-email: An interface privacy filter that visually masks email addresses in Claude's output until hovered over [00:33, 02:49].
Plugin Configuration: Setting up plugin.json and adding a "modules" field to hooks.json referencing TypeScript entry files [00:37].
Middleware Pattern Explanation: Walkthrough of the ($, e, next) signature used by event hooks, detailing how `--- id: claude-mods-in-claude-code url: https://www.youtube.com/watch?v=yUuFvL1lK4k title: "Mods in Claude Code: change how Claude Code works" channel: "Claude" published: 2026-10-05 related_entries: [2026-10-01-claude-code-mods] kind: official added_by: "" description_status: pending views: 5249 views_checked: 2026-10-05

Related events

2026-09-23Claude Code silently ignored AGENTS.md when telemetry was off; fixed in v2.1.281 ★★
2026-09-30universal-modder: open-source Claude Code plugin that mods almost any PC game, from a fal engineer ★★

Sources (4)

id: 2026-10-01-claude-code-mods · updated 2026-10-02 · open in the interactive timeline