Third-Party Slash Commands

Atom packs can contribute slash commands with defineCommand() from @monad/sdk-atom. Commands are host-run actions: the daemon owns parsing, permission checks, conflict resolution, and execution. The web composer, CLI, ACP clients, and /help all discover the same command metadata from /v1/commands.

Minimal command

import { defineCommand } from '@monad/sdk-atom';

export const pingCommand = defineCommand({
  name: 'ping',
  description: 'Ping the demo atom pack',
  async run(ctx, args) {
    const message = args.trim();
    return { message: message ? `pong: ${message}` : 'pong' };
  }
});

When installed from an atom pack named multi-demo, the command is always addressable as /multi-demo.ping. The bare /ping form is available when it does not collide with a built-in or a pinned command from another pack.

Structured arguments

Use args to describe positional arguments for autocomplete and display. Execution still receives the raw args string; command code remains responsible for its final validation.

export const pingCommand = defineCommand({
  name: 'ping',
  description: 'Ping the demo atom pack',
  args: [{ name: 'message', type: 'string', required: false, placeholder: '[message]' }],
  async run(ctx, args) {
    return { message: args.trim() ? `pong: ${args.trim()}` : 'pong' };
  }
});

Supported argument types:

Type	Use
`string`	Free text. No value autocomplete.
`enum`	Static choices from `values`.
`model`	Current model profiles supplied by the host UI.
`session`	Current session list supplied by the host UI.
`path`	Filesystem path input. UIs may offer a picker or plain text.
`boolean`	Boolean input.
`number`	Numeric input.

enum values look like this:

args: [
  {
    name: 'level',
    type: 'enum',
    required: false,
    values: [
      { id: '1', name: 'L1', description: 'Facts only' },
      { id: '2', name: 'L2', description: 'Facts and graph' }
    ]
  }
];

Subcommands

Commands may expose one level of subcommands. This is discovery metadata for the composer; the daemon still invokes the parent command and passes the remaining text as raw args.

export const memoryCommand = defineCommand({
  name: 'memory',
  description: 'Manage memory',
  subcommands: [
    {
      id: 'check',
      name: 'Check',
      description: 'Check memory contradictions'
    },
    {
      id: 'consolidate',
      name: 'Consolidate',
      description: 'Consolidate memory layers',
      args: [{ name: 'level', type: 'number', required: false, placeholder: '[level]' }]
    }
  ],
  async run(ctx, args) {
    const [subcommand, ...rest] = args.trim().split(/\s+/);
    if (subcommand === 'check') {
      const { flagged } = await ctx.checkMemory();
      return { message: `Flagged ${flagged} contradictions.` };
    }
    if (subcommand === 'consolidate') {
      const level = Number.parseInt(rest[0] ?? '', 10);
      const result = await ctx.consolidate(level >= 1 && level <= 3 ? level : undefined);
      return { message: `Consolidated through level ${result.level}.` };
    }
    return { message: 'Usage: /memory <check|consolidate> [level]' };
  }
});

The composer behavior is:

/memory suggests check and consolidate.
/memory consolidate uses the consolidate.args metadata for argument suggestions.
/memory anything is still sent to the parent memory command; your run() function decides whether it is valid.

Monad intentionally supports only one subcommand level for now. It does not support nested subcommand groups or a full flag parser in command metadata.

Command metadata

type CommandDefinition = {
  name: string;
  aliases?: string[];
  description: string;
  argHint?: string;
  args?: CommandArg[];
  subcommands?: CommandSubcommandDefinition[];
  highRisk?: boolean;
  duringTurn?: boolean;
  run(ctx: CommandRunContext, args: string): Promise<CommandResult>;
};

Two fields the example above omits: descriptionKey (an i18n message id — the localized text replaces description when the registry lists commands with a translator) and group (a product grouping for help and discovery surfaces). duringTurn defaults to false: the host rejects the command with a busy reply rather than letting it race an in-flight run. Use argHint only when a simple text hint is enough or while migrating older commands. Prefer args for new commands because it enables autocomplete.

Boundaries

Built-in command names and aliases are reserved.
Atom-pack command ids are namespaced as <pack>.<command>. The leading / is only the composer trigger prefix, so users run the command as /<pack>.<command>.
id from /v1/commands is the canonical slash token clients insert.
name is user-facing display text only.
The host owns high-risk approval. Set highRisk: true when the command can affect local state, files, credentials, or external services.

Engineering

Architecture

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Infrastructure

Product Design

Third-Party Slash Commands

Minimal command

Structured arguments

Subcommands

Command metadata

Boundaries

​Minimal command

​Structured arguments

​Subcommands

​Command metadata

​Boundaries

Minimal command

Structured arguments

Subcommands

Command metadata

Boundaries