MCP Tools¶

All registered skills and enabled workflows are automatically exposed as MCP tools. Clients discover them via the standard tools/list method.

Naming Convention¶

Tool Discovery¶

Tools are registered on the Anubis frame during init/2. Each tool includes:

• name — the skill: or workflow: prefixed identifier
• description — from the skill module's description/0 callback, or the workflow's description field
• input_schema — Peri-compatible type definitions converted to JSON Schema by Anubis

Dynamic skills are tagged with [dynamic] in their description.

Dynamic Refresh¶

When skills are loaded, unloaded, or reloaded at runtime, the MCP server:

1. Receives a PubSub event on the "skills:registry" topic
2. Re-registers all tools on the frame
3. Sends a notifications/tools/list_changed notification to connected clients
4. Clients automatically re-fetch the tool list

This means newly loaded dynamic skills appear in MCP clients without reconnecting.

Input Schema¶

Core skills have typed config schemas. For example, skill:web_search:

{
  "input": { "type": "string", "description": "Input data passed to the skill" },
  "config": { "type": "object" },
  "query": { "type": "string", "description": "Search query string" },
  "max_results": { "type": "integer", "description": "Maximum results to return" }
}

Dynamic skills use a generic schema with input and config fields.

Execution Flow¶

When a client calls a tool:

1. Resolve — skill name looked up in SkillRegistry, or workflow found by name
2. Policy check — PolicyEngine.evaluate/2 with :mcp caller type (see Policy Enforcement)
3. Execute — skill runs in a supervised task with a capability token
4. Timeout — configurable via mcp.tool_timeout_ms (default 30 seconds)
5. Response — result mapped to Anubis.Server.Response format

Timeout Handling¶

Tool execution has a configurable timeout:

Config key: mcp.tool_timeout_ms
Default: 30000 (30 seconds)

If a tool exceeds the timeout, the task is shut down and an error response is returned:

{"type": "text", "text": "Tool execution timed out", "isError": true}

Error Responses¶

Available Tools¶

The exact tool list depends on your registered skills. Use tools/list from your MCP client, or check the /metrics endpoint for the current count.

Typical installation exposes ~29 skill tools and ~5 workflow tools.