---
url: /api/@ufo-soft/caelus.md
---
# @ufo-soft/caelus

Define a command once. Dispatch it from anywhere: a button, a key chord, a
CLI subcommand, an MCP tool call.

A command registry: commands are self-describing runtime objects, so any
surface can project them outward without core knowing that surface exists.

## Core

Zero dependencies. `src/core.ts` is the whole thing.

```ts
import { Registry, ok, failed } from '@ufo-soft/caelus'

const registry = new Registry()

registry.register({
  name: 'add',
  command: {
    description: 'Add a todo',
    parameters: [{ name: 'text', type: 'string', description: 'The todo text' }],
  },
  handler: ({ text }) => {
    if (typeof text !== 'string') return failed('text must be a string')
    store.add(text)
    return ok()
  },
})

await registry.invoke('add', { text: 'write it down' })
```

## Keybindings

`@ufo-soft/caelus/keybindings`. Defaults are a plain object, the user patch is
a parsed TOML file, and one `keydown` listener dispatches through the registry.

## Modules

* [core](core/index.md)
* [keybindings](keybindings/index.md)