ormusClaude Code mods
Claude Code mods

Change what Claude Code does, and what it draws.

A mod is a small plugin of function hooks. It can block a tool call, rewrite a prompt, open a pane beside the transcript, paint pixels in the terminal, or restyle Claude Code's own interface. Everything here was recorded in real sessions, with working mods you can download.

Read the field guide Get the demo mods
Ghostty running Claude Code with the draw-lab mod: an animated plasma raster in a side pane, Bash calls drawn as bordered cards, a custom turn timer and a custom prompt hint.
Claude Code 2.1.289 in Ghostty, running draw-lab. The pane on the right and the cards in the transcript are drawn by the mod.
Anatomy

A plugin folder and one function

The hooks module exports register(on). Each on(event, matcher?, hook) adds a hook, and every hook gets ($, e, next): the engine, the event, and the rest of the chain. Return without calling next to answer for yourself.

  • .claude-plugin/plugin.jsonName, version, description
  • hooks/hooks.json{ "modules": ["./register.tsx"] }
  • hooks/register.tsxTypeScript, with JSX for drawing
export const register: Register = on => {
  on('tool.call', { tool: 'Edit' }, ($, e, next) =>
    PROTECTED.test(e.file_path)
      ? { deny: `${e.file_path} is protected here.` }
      : next(e),
  )

  on('turn.complete', async ($, e, next) => {
    $.ui.toast(`Turn done: ${tools} tool calls`)
    return next(e)
  })
}
Capabilities, as recorded

What a mod can do

Claude Code showing an edit to .env blocked by a mod hook.

Guard tool calls

See every call before it runs. Deny it with a reason Claude reads, or rewrite its input.
A band above the prompt reading: mods-tour last turn 8s, 3 tool calls.
A status line entry reading mods-tour: 3 tool calls this turn.

Bands, status lines, toasts

Small readouts that redraw on their own when the state they read changes.
A mod pane with buttons, a select, a text input, Markdown and highlighted code.

Panes with real controls

Buttons, inputs and selects whose handlers run in your mod. Markdown and code use Claude Code's own renderers.
An animated plasma field in rainbow colours, drawn with half-block characters.

Pixels in the terminal

A Raster repaints a grid of truecolour cells 15 times a second. An Image shows real pixels in Ghostty and kitty.
Conway's Game of Life running in a mod pane.

Modules with their own loop

A Client runs on the drawing thread with its own clock, keys and pointer. Good for games.
Claude Code's transcript with each Bash call redrawn as a bordered card.

Restyle Claude Code

Redraw tool calls, the spinner, the turn timer and the prompt hint. Fifteen render sites in all.
Demo mods

Four mods, with source and tests

Pixel panes

Ten looks for a mod pane, drawn live

Mockups on a real 128×36 cell grid, using only what a mod can draw: half blocks, braille and Image.

See all ten
Development loop

Write, check, load

  1. Write the files. No scaffolding. Claude Code writes this build's types next to the mod as it loads, so tsc works with no setup.
  2. Validate. claude plugin validate <folder> lists every hook and $ call, and anything the engine would refuse.
  3. Test. claude plugin test <folder> runs *.test.ts files against the real engine.
  4. Load. claude --plugin-dir <folder>, or turn on hot reloading and the mod reloads after each edit.