MCP Reference

The MCP surface exposes the deployment's recipes as MCP tools. It is not a second, hand-maintained tool list — the tool list is the recipe registry. Adding a query pattern is adding a registry row; the tool list updates with no code change, exactly as the API's /recipes and the CLI's remember query list do. All three render the same surface.

tools/list

Returns one tool per active recipe. Each tool carries its name, description, and a JSON-Schema inputSchema built from the recipe's typed parameters:

{
  "tools": [
    {
      "name": "relation_current",
      "description": "Current relations matching a subject and optional predicate …",
      "inputSchema": {
        "type": "object",
        "properties": {
          "subject_entity_id": { "type": "string", "format": "uuid" },
          "predicate": { "type": "string" }
        },
        "required": ["subject_entity_id"]
      }
    }
  ]
}

The inputSchema is the contract an MCP client validates arguments against before calling — the same schema the API advertises at /recipes.

tools/call

Runs the named recipe over its arguments and returns the envelope serialized to JSON in one text content block:

{
  "content": [{ "type": "text", "text": "{ \"grain\": \"fact\", \"facts\": [ … ] }" }],
  "isError": false
}

A tool the registry has no active row for, or a call missing a required argument, is a protocol error result (isError: true) with the reason in the text block — never an exception across the wire. The client re-plans against a stated failure.

What the tools return

Every tool returns the self-accounting envelope: the answer, its grain (fact / evidence / compiled / composite), its validity and freshness, and any typed negative. Because the grain travels with the answer, a client can tell a current-fact answer from what a source asserted — a recipe that answers "what holds now" can never be one that returns evidence (the registry's grain bar guarantees it).

Transport

Run remember mcp to start the dependency-light stdio JSON-RPC server. It reaches the deployment at REMEMBERSTACK_API_URL, uses REMEMBERSTACK_API_AUTHORIZATION when set, renders tools/list from GET /recipes, and proxies tools/call to POST /recipe/{name}. The server supports the MCP initialize, tools/list, and tools/call lifecycle; notifications produce no response.

The recipe registry and execution remain deployment-side. The MCP process is therefore a client transport, not another server composition and not a second tool registry.