MCP (Model Context Protocol)¶

Integration with MCP servers for extended tool capabilities.

Overview¶

MCP allows robots to connect to external tool servers, extending their capabilities without modifying robot code. RobotLab provides an MCP client that communicates with MCP-compliant servers over multiple transport types.

robot = Robot.new(
  name: "developer",
  system_prompt: "You help with coding tasks.",
  mcp: [
    {
      name: "filesystem",
      transport: { type: "stdio", command: "npx @modelcontextprotocol/server-filesystem" }
    }
  ]
)

Components¶

Component	Description
Client	Connects to MCP servers, lists tools, calls tools
Server	Server configuration data structure
Transports	Communication methods (stdio, WebSocket, SSE, HTTP)

Quick Start¶

Using MCP with a Robot¶

Pass MCP server configurations via the mcp: parameter when creating a robot:

robot = Robot.new(
  name: "assistant",
  template: :assistant,
  mcp: [
    { name: "github", transport: { type: "stdio", command: "mcp-server-github" } }
  ]
)

result = robot.run("List my open pull requests")
result.last_text_content

MCP in Networks¶

Robots in a network can inherit MCP servers from the network or define their own:

network_mcp = [
  { name: "github", transport: { type: "stdio", command: "mcp-server-github" } }
]

robot = Robot.new(
  name: "assistant",
  template: :assistant,
  mcp: :inherit  # Use network's MCP servers
)

Direct Client Usage¶

client = RobotLab::MCP::Client.new(
  name: "filesystem",
  transport: { type: "stdio", command: "mcp-server-filesystem", args: ["--root", "/data"] }
)

client.connect
tools = client.list_tools
result = client.call_tool("readFile", { path: "/data/config.yml" })
client.disconnect

Transport Types¶

Type	Config Key	Use Case
`stdio`	`"stdio"`	Local command/subprocess execution
`websocket`	`"ws"` or `"websocket"`	Real-time bidirectional communication
`sse`	`"sse"`	Server-sent events streaming
`streamable-http`	`"streamable-http"` or `"http"`	HTTP request/response with session support

MCP Parameter Values¶

The mcp: parameter on a Robot accepts three types of values:

Value	Meaning
`:none`	No MCP servers (explicitly disabled)
`:inherit`	Use the network's MCP servers
`Array<Hash>`	Explicit list of server configurations

Each server configuration hash requires:

Key	Type	Description
`name`	`String`	Unique server identifier
`transport`	`Hash`	Transport configuration (must include `type`)

Error Handling¶

MCP operations raise RobotLab::MCPError when:

Connection to a server fails
A request is made without an active connection
An unsupported transport type is specified

begin
  client.connect
  client.call_tool("unknown_tool", {})
rescue RobotLab::MCPError => e
  puts "MCP error: #{e.message}"
end