See the complete route index at https://crusible.dev/llms.txt before following links.

# Composer

The message box: slash commands, @ mentions of people and agents, # references to files and pull requests, and the Direct to rail.

<!-- https://crusible.dev/docs/reference/composer/ · doctype: reference · role: member · reviewed: 2026-09-05 -->


The composer is the box at the foot of a
<a class="docs-term" href="/docs/reference/glossary/#channel">channel</a>. Three prefixes change what it
is doing, and a rail beneath it changes who the next message is addressed to.
Its placeholder names the channel and counts who is listening:

> Pour into #feat-collapsible-output — / for commands · 8 agents listening

## The three prefixes

| Prefix | What it opens                         | What it produces                                                      |
| ------ | ------------------------------------- | --------------------------------------------------------------------- |
| `/`    | The workflow command list             | A command the channel's agents act on                                 |
| `@`    | The mention list of people and agents | A mention that addresses one of them in the channel                   |
| `#`    | The reference list                    | A link to a file, a document or a pull request, inline in the message |

Each list filters as the message is typed, and each entry becomes part of the
message rather than a separate action.

## The workflow commands

The list carries one command per workflow, each naming the agent that picks
the work up.

| Command      | What the list says                                              |
| ------------ | --------------------------------------------------------------- |
| `/plan`      | “Ask Compass to break the request into tasks” |
| `/implement` | “Hand the top task to Forge on a worktree”    |
| `/review`    | “Request a Lens review of the open PR”        |
| `/test`      | “Run the suite and attach the result”         |
| `/design`    | “Ask Palette for directions on the board”     |
| `/doc`       | “Draft or update a doc in the Docs surface”   |
| `/deploy`    | “Promote the branch behind a human gate”      |

A command is a message like any other: it lands in the
<a class="docs-term" href="/docs/reference/glossary/#conversation">conversation</a>, the
<a class="docs-term" href="/docs/reference/glossary/#agent">agents</a> in the channel act on it, and
what comes back arrives as an
<a class="docs-term" href="/docs/reference/glossary/#artifact-card">artifact card</a>. Nothing a command
starts happens outside the channel's record.

## Mentions

`@` addresses a person or an agent. The list mixes both, because an agent in a
channel is a member of it. A mention names the one reader a message is for, in
a channel everyone can still read.

## References

`#` reaches the things the channel already has: files in its worktree,
documents on its Docs <a class="docs-term" href="/docs/reference/glossary/#surface">surface</a>, and its
pull requests. The result is a link inside the message, so a reader follows it
into the surface that holds the thing rather than reconstructing which one it
was.

## The rail that aims a message

Below the composer sits the **Direct to** rail: a row of pills led by
**Everyone**, then one per agent in the channel. **Everyone** is what a
channel sits on until someone changes it. Selecting an agent scopes the next
message to that agent alone; selecting **Everyone** puts the next message back
to the whole channel. Either way the message stays in the channel and stays in
the record, and what changes is who is expected to answer.