cap_mcp_client / cap_mcp_server

Client source: cap_mcp_client.c · header: cap_mcp_client.h · Skill: SKILL.md

Server source: cap_mcp_server.c · header: cap_mcp_server.h · Skill: SKILL.md

Overview

ESP-Claw implements Model Context Protocol (MCP) support through two components, cap_mcp_client and cap_mcp_server:

cap_mcp_client: allows the LLM to discover and call tools exposed by remote MCP servers
cap_mcp_server: exposes the device’s own Capabilities as a local MCP server for external MCP clients

cap_mcp_client

Tool description

Tool ID	Description
`mcp_list_tools`	List available tools on a remote MCP server
`mcp_call_tool`	Call a specified tool on a remote MCP server
`mcp_discover`	Discover MCP servers advertised on the local network

Tool parameters

`mcp_list_tools`

Parameter	Type	Required	Description
`server_url`	string	Yes	MCP server URL
`endpoint`	string		MCP endpoint path
`cursor`	string		Pagination cursor

`mcp_call_tool`

Parameter	Type	Required	Description
`server_url`	string	Yes	MCP server URL
`tool_name`	string	Yes	Tool name to call
`endpoint`	string		MCP endpoint path
`arguments`	object		Arguments passed to the tool

`mcp_discover`

Parameter	Type	Required	Description
`timeout_ms`	integer		Discovery timeout
`include_self`	boolean		Whether to include this device itself

Group information

Property	Value
Group ID	`cap_mcp_client`
Default LLM-visible	No (requires Skill activation)
Tool count	3

cap_mcp_server

Overview

cap_mcp_server is a CLAW_CAP_KIND_HYBRID Capability with lifecycle management. After start, it creates a local MCP server instance and exposes the device’s registered Capabilities as MCP tools for discovery and invocation by external MCP clients on the LAN, such as desktop IDEs or other ESP-Claw devices.

Features

Supports MCP SSE (Server-Sent Events) transport
Automatically maps device Capabilities to MCP tools
Supports mDNS advertisement for LAN discovery
Provides a full lifecycle (init -> start -> stop)

Group information

Property	Value
Group ID	`cap_mcp_server`
Default LLM-visible	No
Tool count	0 (server only; no LLM-callable tools exposed)