Skills & MCP

A skill is a method on any Module decorated with @skill. The decorator makes it an RPC method and publishes it as an MCP tool: the docstring and type annotations become the tool schema the LLM sees.

from dimos.agents.annotation import skill
from dimos.core.module import Module

class MySkillContainer(Module):
    @skill
    def wave_hello(self) -> str:
        """Wave at the nearest person."""
        # ... robot control logic ...
        return "Waving!"

The contract

Parameters must be JSON-serializable primitives (str, int, float, bool, list, dict).
The docstring is the tool description. It is not documentation for humans; it is the only context the LLM has about when and how to call this skill. Write it the way you would brief an operator: what it does, when to use it, an example call.
Return a string or an image. The return value goes into the agent’s conversation history and drives its next decision. “Done” is a bad return; “Moved 0.5 m forward, now facing the door” is a good one.
Skills live in ordinary modules, so they can hold streams, state, and Spec references to other modules (a navigation skill holds a reference to the navigation module and calls set_goal on it).

From skill to tool: the two MCP modules

Every agentic blueprint includes both halves:

McpServer (dimos/agents/mcp/mcp_server.py) discovers every @skill method across all deployed modules via RPC and serves them as MCP tools over HTTP on port 9990. Any MCP-capable client can connect - the DimOS agent, the CLI, or an external tool like Claude Code.
McpClient (dimos/agents/mcp/mcp_client.py) is the built-in LLM agent. At startup it calls tools/list on the server and hands the tools to the model.

This split is the point: the skill surface exists independently of any LLM.

Drive skills without an LLM

Prove your stack works before involving a model. With any agentic blueprint running:

dimos mcp list-tools                              # every skill, with its schema
dimos mcp call relative_move --arg forward=0.5    # call one directly
dimos mcp status                                  # server status

--arg takes KEY=VALUE pairs and JSON-decodes the values, so lists and numbers work too. If a skill misbehaves here, it will misbehave worse under an LLM. Debug at this layer first.

Built-in skills

The ground truth is always dimos mcp list-tools on your running stack. The common ones on the Go2 agentic blueprint:

Skill	Module	Description
`relative_move(forward, left, degrees)`	`UnitreeSkillContainer`	Move relative to current position
`execute_sport_command(command_name)`	`UnitreeSkillContainer`	Unitree sport commands (sit, stand, flip, …)
`wait(seconds)`	`UnitreeSkillContainer`	Pause execution
`observe()`	`GO2Connection`	Capture and return the current camera frame
`navigate_with_text(query)`	`NavigationSkillContainer`	Navigate to a place by description
`tag_location(location_name)`	`NavigationSkillContainer`	Tag the current position for later recall
`stop_navigation()`	`NavigationSkillContainer`	Cancel the current navigation goal
`follow_person(...)`	`PersonFollowSkillContainer`	Visually follow a described person
`speak(text)`	`SpeakSkill`	Text-to-speech
`where_am_i()`	`GoogleMapsSkillContainer`	Current street/area from GPS
`map_query(query)`	`OsmSkill`	Search OpenStreetMap with a VLM

System prompts

The system prompt is robot policy, not boilerplate. The default Go2 prompt (dimos/agents/system_prompt.py) tells the agent what robot it controls, what its skills do, and how to behave with people around. If you add or remove skills, update the prompt to match - an agent prompted about skills that do not exist will hallucinate calls to them, and an agent not told about a new skill will underuse it. Set it per-blueprint: McpClient.blueprint(system_prompt=...).

Tutorial: add your own skill - end to end, verified at each step
Tutorial: drive the Go2 with language

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The contract

From skill to tool: the two MCP modules

Drive skills without an LLM

Built-in skills

System prompts

Next

​The contract

​From skill to tool: the two MCP modules

​Drive skills without an LLM

​Built-in skills

​System prompts

​Next

The contract

From skill to tool: the two MCP modules

Drive skills without an LLM

Built-in skills

System prompts

Next