MCP Tool
An MCP tool is a callable function exposed by an MCP server that an AI agent can invoke to perform actions in the world. Tools are the primary mechanism through which agents extend their capabilities beyond text generation — enabling them to interact with external systems, APIs, file systems, and services.
Anatomy of an MCP Tool
Each MCP tool has:
- → Name — A unique identifier (e.g.,
createTask,reply) - → Description — Natural language explanation of what the tool does (used by the LLM to decide when to call it)
- → Input schema — JSON Schema defining the parameters the tool accepts
- → Response — The data returned to the agent after the tool executes
AgentRQ MCP Tools
AgentRQ exposes the following tools to Claude Code agents:
| Tool | Parameters | Description |
|---|---|---|
createTask |
title, description, status |
Create a task on the task board |
reply |
chat_id, message |
Send a message to the human |
getTaskMessages |
chat_id |
Retrieve conversation history |
updateTaskStatus |
task_id, status |
Set a task to ongoing or completed |
downloadAttachment |
attachment_id |
Retrieve a file attachment |
getWorkspace |
— | Get workspace configuration |
How the Agent Uses Tools
When a tool is available, the LLM can choose to call it by generating a structured tool call in its response. The MCP client intercepts this, executes the tool call against the server, and returns the result to the model as a new context entry.
`
- Model generates: { "tool": "reply", "params": { "chat_id": "...", "message": "Done!" } }
- MCP client calls AgentRQ's reply endpoint
- AgentRQ delivers the message to the human's task board
- MCP client returns: { "success": true } to the model
- Model continues reasoning with updated context
`
Related Terms
- → MCP
- → MCP Server
- → MCP Client
- → Tool Use
- → Task