MCP reference

Status: draft. judgevet-mcp requires the optional mcp extra. It serves MCP over stdio: stdout is protocol traffic and stderr is diagnostics. For installation, host configuration and discovery, use Connect MCP.

Tool arguments

Discovery exposes exactly these three tools. All require state and instruction (singular). instruction is a string. The published schema allows a string or object for state.

Tool	Additional argument	Default when omitted
ask_noul	None	No criteria argument is exposed.
ask_choice	criteria: object mapping labels to descriptions	{"yes":"Yes","no":"No"}
ask_score	criteria: array of ordered rubric descriptions	["Poor","Fair","Good","Excellent"]

The tool definitions are the source for these local schemas. Their prose currently mentions arrays for state, but the actual state schema excludes arrays. Use string/object state for host calls; do not infer array support from that description. The schemas do not specify item/value schemas for criteria or additionalProperties: false. Handlers are not a substitute for full schema validation.

Each tool constructs one named question and calls the sync port with model="jev-latest". Tool arguments cannot select a model or acceptance policy. The internal question names are noul_question, choice_question and score_question. Host argument instruction becomes wire instructions. See configuration overrides.

Successful answers

A successful call returns a text content item and structured content. Python SDK attributes use structured_content and is_error; wire JSON fields use structuredContent and isError. This distinction is recorded in the adapter's SDK citations.

Tool	Structured fields
ask_noul	noul, model, usage
ask_choice	choice, confidence, probabilities, model, usage
ask_score	score, confidence, probabilities, legend, model, usage

usage contains input_tokens and output_tokens. Structured content contains the single answer's fields directly, not the CLI's answers envelope. JSON object keys for Score levels are strings on the wire. Field semantics and vendor citations are in the Python API reference. Text content formats the answer for reading; use structured values for programmatic access. A successful call is a judgment, not evidence of its correctness.

Failure and lifecycle behavior

Missing state/instruction, unknown tools and missing expected answers raise ValueError in the handlers. A wrong answer variant raises TypeError. Service errors propagate to the MCP runtime, which presents protocol failures. A tool failure is not a negative Noul answer or an unmet policy. Do not assume protocol error text has been scrubbed; see diagnostic limits.

The entry point constructs and closes the adapter around serving. It returns 2 for missing runtime, invalid settings or missing key, and 130 for keyboard interruption. EOF ends the stdio session. The tested SDK baseline and legacy initialization path are recorded in the adapter source; an unexercised protocol path is not promoted by those tests. Intermittent host initialization failures have no established remedy; use connection checks.

For embedding, create_mcp_server(port) accepts a SystemOnePort. The factory does not construct or close the caller's port. This entry point stays in the optional inbound adapter; importing the base library does not require MCP.