Jean-Pierre

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Referenced byT-0vmwqfq

Let a plugin's query request ask for structured output ​

  • Status: Done
  • Kind: Feature
  • Authors: jp
  • Date: 2026-10-01
  • Label: domain=plugins
  • Label: package=jp_cli
  • Label: package=jp_plugin

A plugin can run a turn through the host with query, but QueryRequest carries only conversation, content, new, title, and cfg (crates/jp_plugin/src/message.rs:496-536). There is no way to ask for a response that matches a JSON Schema, or to run the turn in a throwaway conversation that is not kept.

Input that hits it: RFD 116's jp rfd track reads an RFD's Implementation Plan as structured output. The recipe does it with jp query --new --local --tmp=5m --format=json --no-reasoning --no-tools --schema "$SCHEMA" (justfile:2703-2704). The plugin cannot ask its host for the same, so it shells out to jp query as a subprocess.

The subprocess works and is cheap, so this is a cleanup, not a blocker.

Scope ​

  • schema: draft D18 (Plugin Event Subscriptions and Query Delegation) already specifies it on the query payload, as the same field ChatRequest carries. This ticket ships that field on its own, ahead of the rest of D18.
  • A temporary conversation, the way --local --tmp gives one: not in D18. Without it, a plugin's one-off structured query leaves a conversation behind.

Reasoning and tools can likely be switched off through the existing cfg field; check that before adding fields for them.

Comments ​

  • From: jp
  • Date: 2026-10-01T10:26:09Z

Implemented; protocol bumped to 11.

  • query.schema: set on the turn's ChatRequest, as jp query --schema does. query_complete carries the parsed response in a new data field. A turn whose own response has no structured data is answered with an error; only the last turn is searched, so an earlier turn's data is never returned in its place.
  • query.expires_in: a humantime duration (5m, 1h, 0s) stamped as expires_at on the conversation a new query creates. Refused without new, matching --tmp requiring --new.

The rest of the recipe's flags go through cfg on the same request (key paths checked against the config tree, not exercised by a test):

  • --local: conversation.start_local=true
  • --no-reasoning: assistant.model.parameters.reasoning=off
  • --no-tools: no exact equivalent. assistant.tool_choice=none forbids tool calls, but the tools are still sent with the request.
  • From: jp
  • Date: 2026-10-01T11:41:01Z

Review follow-up (PR #1221):

  • A turn stopped before it starts (a client stop or Ctrl-C during MCP startup, model lookup, or before the loop's first phase) returned Ok(()), so query_complete handed back the previous turn's data. TurnInputs::run returns a TurnOutcome (Started / NotStarted), and a structured query on a turn that did not start is answered with an error.
  • A response that is not valid JSON is recorded as its raw text in a JSON string, which query_complete passed off as data. That string is refused when the schema's root type rules a string out (most often a response cut off at the output token limit).

Both go through turn_structured_data in cmd::query, which jp query --schema uses too. The CLI had both problems as well, and worse: it searched the whole stream rather than the last turn. A turn that did not start also no longer deletes the query draft, which is the only copy of a request that was never recorded.

  • From: jp
  • Date: 2026-10-01T12:30:53Z
  • Re: #2

Review follow-up (PR #1221, second round): TurnOutcome and the coordinator's started flag are gone, and TurnInputs::run, Query::run_turn, and run_turn_loop return Result<()> again.

Callers read last_request_id (the id of the conversation's last ChatRequest) from the lock before the turn runs, and turn_structured_data takes that id: if the last request is unchanged, the turn did not start. The same comparison gates deleting the query draft in jp query.

The marker is the last request, not the last TurnStart: sanitizing the stream before the turn can drop a trailing empty TurnStart or insert one into a stream that has none, but never adds or removes a request. turn_structured_data_refuses_a_turn_that_did_not_start_after_sanitizing fails against a TurnStart-based check.