Slash Commands

Agents can advertise a set of slash commands that users can invoke. These commands provide quick access to specific agent capabilities and workflows. Commands are run as part of regular prompt requests where the Client includes the command text in the prompt.

Advertising commands

After creating a session, the Agent MAY send a list of available commands via the available_commands_update session notification:

{
  "jsonrpc": "2.0",
  "method": "session/update",
  "params": {
    "sessionId": "sess_abc123def456",
    "update": {
      "sessionUpdate": "available_commands_update",
      "availableCommands": [
        {
          "name": "web",
          "description": "Search the web for information",
          "input": {
            "type": "text",
            "hint": "query to search for"
          }
        },
        {
          "name": "test",
          "description": "Run tests for the current project"
        },
        {
          "name": "plan",
          "description": "Create a detailed implementation plan",
          "input": {
            "type": "text",
            "hint": "description of what to plan"
          }
        }
      ]
    }
  }
}

availableCommands

AvailableCommand[]

The list of commands available in this session

AvailableCommand

name

string

required

The command name (e.g., “web”, “test”, “plan”)

description

string

required

Human-readable description of what the command does

input

AvailableCommandInput

Optional input specification for the command

AvailableCommandInput

Currently supports text input with type: "text":

hint

string

required

A hint to display when the input hasn’t been provided yet

Command input specifications can add custom or future type values. Custom input types MUST begin with _; unknown non-underscore input types are reserved for future ACP variants. Clients that cannot render an input specification should preserve it when storing, replaying, proxying, or forwarding command metadata, and otherwise display the command without structured input.

Dynamic updates

The Agent can update the list of available commands at any time during a session by sending another available_commands_update notification. This allows commands to be added based on context, removed when no longer relevant, or modified with updated descriptions.

Running commands

Commands are included as regular user messages in prompt requests:

{
  "jsonrpc": "2.0",
  "id": 3,
  "method": "session/prompt",
  "params": {
    "sessionId": "sess_abc123def456",
    "prompt": [
      {
        "type": "text",
        "text": "/web agent client protocol"
      }
    ]
  }
}

The Agent recognizes the command prefix and processes it accordingly. Commands may be accompanied by any other user message content types (images, audio, etc.) in the same prompt array.

Get Started

Protocol

Libraries

Advertising commands

AvailableCommand

AvailableCommandInput

Dynamic updates

Running commands

​Advertising commands

​AvailableCommand

​AvailableCommandInput

​Dynamic updates

​Running commands

Advertising commands

AvailableCommand

AvailableCommandInput

Dynamic updates

Running commands