SpyBara
Go Premium

plugins/mods/overview.md 2026-10-22 22:58 UTC to 2026-10-23 22:59 UTC

This page contains 56 additions and 56 deletions.

2026
Thu 1 23:59 Fri 2 22:59 Mon 5 23:58 Thu 8 22:58 Wed 14 22:58 Thu 15 23:58 Mon 19 23:58 Tue 20 23:00 Thu 22 22:58 Fri 23 22:59

Mods overview

Add panes, commands, and tool call rules to Claude Code with a mod. See what a mod can do, how to make or install one, and where mods run.

A mod is a plugin that changes how Claude Code looks and behaves. It's made of JavaScript or TypeScript event handlers: Claude Code calls one when an event happens, such as a tool call, a submitted prompt, or a part of the interface being drawn, and the handler can watch the event, change it, or take it over. Use a mod to add a feature of your own to Claude Code, such as a pane that charts how full your context is after each request. For the files in a mod and a complete example, see How a mod works.

[!NOTE]

Claude Code's existing hooks also run on events, as a shell command, HTTP request, or prompt you configure in a settings file. A mod's handlers are functions that run inside Claude Code instead. Claude Code calls both kinds hooks: on these pages, "hook" means a mod's handler, and the settings-file kind is a "settings hook".

What a mod can do

Settings hooks, skills, status lines, and MCP servers work from outside Claude Code: each one runs a script, or gives Claude text or tools. A mod runs inside Claude Code, so it can do things they can't:

  • Draw an interface you can use: a pane beside the transcript or a band above the prompt, with tabs, buttons, and text fields. See Draw in the interface.
  • Redraw Claude Code's own interface: replace or restyle parts Claude Code draws itself, such as a tool call's row, the spinner, or the dialog Claude asks questions in. See Change what Claude Code already draws.
  • Step into a tool call or a request: for example, hold a tool call while you ask the user a question, answer it without running the tool, or send one request to a different model. See Guard or change a tool call and Follow a turn.
  • Run your own code on a command: a /command that runs your function at once, with no Claude turn, even while Claude is working. See Add a command or a tool.
  • Share data between hooks: a mod's hooks share the variables in its file, so what one hook records, another can show. For example, one hook can count tool calls while another shows the count beside the spinner, or one can read each request's token usage while another charts it in a pane. See React to events.

Mods work in the Claude Code CLI, the Code tab of the Claude Desktop app, and the VS Code extension. See Where mods run for how they behave elsewhere, such as in claude -p and cloud sessions. If a settings hook, a skill, or an MCP server already does what you need, compare them before you write a mod. To manage mods for an organization, see Manage mods for your organization.

Get a mod

To start with a mod:

Install or update a mod

[!WARNING]

A mod is code that runs with your permissions. It can read and write your files, start processes, and make network requests. Install mods only from authors and marketplaces you trust. See Decide whether to trust a mod.

A mod installs as a plugin, from a marketplace. Give the plugin's name, an @, and the marketplace's name. These examples install a plugin named token-chart from a marketplace named your-org:

  • In a Claude Code session, run /plugin install token-chart@your-org.
  • In your shell, run claude plugin install token-chart@your-org.

Install plugins covers marketplaces, scopes, the VS Code extension and the Desktop app, and keeping plugins updated, all of which apply to a plugin that contains a mod without changes.

If you install or update a mod from your shell while a session is open, run /reload-plugins in that session to load it. Otherwise it loads the next time you start Claude Code.

Try a sample mod

Anthropic shares sample mods in the claude-code/mods directory of the claude-code-playground repository. Each one is a complete plugin, and its README says how it was built. The repository shares them as they are, without support.

  • token-weather: draws a forecast of your context window above the prompt
  • blast-radius: holds a risky shell command, such as rm -rf or a force push, and shows what it would change, with buttons to proceed or cancel
  • replay-theater: adds a /replay command that steps through the file edits Claude made in the last turn

A sample mod runs with your permissions. To see what one does before you load it, list its hooks and calls.

To try one, clone the repository and load the mod's directory for one session with --plugin-dir. To confirm the mod loaded, check which mods the session loaded.

To keep one, add the clone's claude-code/mods directory as a marketplace, then install the mod from claude-code-playground-mods. The marketplace points at your clone, so the mod stops loading if you move or delete it.

Decide whether to trust a mod

A mod is code that runs with your permissions, inside Claude Code. Install mods only from authors and marketplaces you trust.

What a mod can reach

A mod runs with your permissions, so before you install one, know what it has access to. Once it loads, a mod can:

  • Act on your machine as you: read and write files anywhere your user account can, start programs, and make network requests
  • Read your secrets: environment variables and settings files, including an API key you keep in either
  • See your session: every prompt you send and every tool call Claude makes
  • Change your session: rewrite a prompt or a tool call, submit a prompt as if you had typed it, or send a message to another of your sessions
  • Act without asking you: approve a tool call before you're asked
  • Spend your usage: call a model on your plan or API key

Mods aren't sandboxed. If you turn on sandboxing, the sandbox isolates the Bash commands Claude runs, and a process that a mod starts runs outside it.

With managed settings or a Team or Enterprise /login as the session's credential, by default a mod's approval doesn't get a call past your ask rules or PreToolUse hooks. Without either, a mod can approve a call that an ask rule would prompt for, or that your PreToolUse hook blocked. To check when a mod can also approve a call that a deny rule refuses, see Extend permissions with hooks.

A mod can restyle much of Claude Code's interface, but not the permission prompt. It can't change what a prompt shows you.

List what a mod does before you install one

Before you install a mod, you can list which events it handles and what it asks Claude Code to do, such as read a file or make a network request, without running it. Get the plugin's files first, for example by cloning its repository. Then, in your shell, run claude plugin validate on the plugin's directory:

claude plugin validate ./some-mod

The hooks: and calls: lines in the output list the events the mod handles and what it asks Claude Code to do. Review what a mod can do shows the output and which calls to look for.

Turn mods on or off

Mods are on by default. In the terminal, use Claude Code v2.1.287 or later. The Desktop app includes its own copy of Claude Code, and mods work there from v2.1.286. Check the version in the place you use mods:

  • Terminal: in your shell, run claude --version. If yours is older, update Claude Code.
  • Desktop app: in a local session in the Code tab, enter /status and read the Claude Code row, which shows a version such as 2.1.286. If yours is older, update the Desktop app.

To turn mods off, choose how many to stop, and for how long. To turn them back on, undo the same change:

  • One mod: disable or uninstall its plugin from the Installed tab in /plugin
  • Every installed mod, for one session: start Claude Code with --safe-mode, which also disables your other customizations
  • Every mod you installed, in every session: set "disableAllHooks": true in ~/.claude/settings.json. Your settings hooks and custom status line stop too. What your organization manages keeps running.

If you use Claude Code through an organization, an administrator can also limit which mods load. Administrators start at Stop user-installed mods from loading.

disableAllHooks and your organization's allowManagedModsOnly stop a mod and leave the rest of its plugin in place: the plugin stays installed, and its skills, commands, agents, and MCP servers load. Other settings and flags reach further. disableAllHooks and What runs under allowManagedHooksOnly list what each one does to a plugin and its settings hooks.

To find out whether mods can load for you, see Check whether mods can load.

[!NOTE]

If you set CLAUDE_CODE_ENABLE_FUNCTION_HOOKS during early access, remove it. Claude Code v2.1.287 and later ignores it, so setting it to 0 doesn't keep mods off.

See which mods a session loaded

To see which mods a terminal session loaded, run /plugin at the Claude Code prompt. A dim line under the tabs gives the count and the names, such as 1 mod active · first-mod. If a mod you installed isn't named there, see Find out why a mod does nothing.

How a mod works

A mod is a plugin whose code registers event handlers, called hooks. Claude Code runs a hook when its event happens, such as when Claude calls a tool or when the spinner is drawn. A small mod has three files:

first-mod/
├── .claude-plugin/
│   └── plugin.json
└── hooks/
    ├── hooks.json
    └── register.js

This is a complete register.js. It counts the tool calls Claude makes and shows the count beside the spinner while Claude works, as in Thinking · tool calls: 3….

// The count, shared by the two hooks below
let calls = 0

// Claude Code calls this once when the mod loads
export function register(on) {
  // Runs each time Claude is about to use a tool
  on('tool.call', async ($, e, next) => {
    calls += 1
    // Ask Claude Code to draw the interface again, so the new count shows
    $.ui.invalidate('ui.render')
    // Let the tool run as usual
    return next(e)
  })

  // Runs each time Claude Code draws the spinner
  on('ui.render', { component: 'Spinner' }, async ($, e, next) => {
    // Keep Claude Code's spinner, with the count added after its word
    return next({ ...e, props: { ...e.props, suffix: ' · tool calls: ' + calls + '…' } })
  })
}

The file registers two hooks, and both use the calls variable at the top:

  • The tool.call hook runs each time Claude is about to use a tool. It adds one to calls, asks Claude Code to draw the interface again, and lets the tool run as usual.
  • The ui.render hook runs each time Claude Code draws the spinner. It keeps Claude Code's own spinner and adds the count after the word.

This recording shows the mod at work. Watch the spinner line above the prompt box: while Claude lists a directory and reads two files, it reads Thinking · tool calls: 1…, then 2…, then 3….