workflow: assign() silently drops the brief — a node only ever receives the task title #1869

Written-by: Chief

workflow/assign takes a brief and silently throws it away. A node is only ever handed the task title, so every instruction that is not inside those 300 characters never reaches the Bot doing the work.

Evidence (plugins/workflow/src/service.js, read on main 2ffd9fc3)

• assign(body) builds the parked task from taskId, title, then optionally acceptance, evidence, callerBotId, projectId. body.brief is never read.
• start() (the other way in) uses body.brief as the title: const title = cleanLine(body.brief || body.title, 300).
• stepBody() hands the node brief: run.task?.title ?? '' — i.e. the title again.

So the two call shapes disagree: start treats brief as a title, assign drops it, and either way the node prompt carries the title.

What that cost tonight

Every dispatch of the 19:10Z batch carried a 20–40 line brief: baseline sha, the exact files and line numbers, the red-first case, the "do not run the full core suite on this host" constraint, the docs/changelog requirement, and the OUTPUT: line the run must print. None of it arrived. The node saw e.g. i1860-build：#1860 Project 团队区（Chief 行 / My agent 行 / 角色池行） and had to guess the rest:

• i1862-build2 and i1855-build2 each ran 45 minutes and died on the step deadline (workflow: a step that is still working is killed at the 45-minute deadline and reported as "no reply" #1868);
• #1854 was dispatched twice into the issue fast line and both runs ended right after triage — the brief that said which files to change was never delivered;
• a "base 09309f74" instruction is meaningless to the node, because the build downloads the live main tarball at run time anyway. Whoever reads the run history sees my brief and believes the pin exists.

This is also why correcting a queued task's baseline is not possible: there is nothing on the task to correct.

Expected

1. assign({ brief }) stores the brief on the task (task.brief) and stepBody passes it as brief; when the task has none, fall back to the title as it does today.
2. start() and assign() agree on what brief means (today one treats it as a title).
3. An unknown field on assign is not silently dropped — at minimum say so in the response, or document the accepted fields on the endpoint.
4. The parked task in workflows.json should show its brief, so a reader can see what the node was actually told.

Reproduction

# assign with a brief the title does not contain
curl -s -X POST .../api/bot -d '{"endpoint":"flybot/workflow/assign","payload":{
  "workflowId":"<lane>","taskId":"probe","title":"probe","brief":"THE-MAGIC-STRING-1234"}}'
# the run's step prompt carries only "probe"; the session never contains THE-MAGIC-STRING-1234

Workaround in use until this lands

Instructions go into the title (300 chars), and the node's own graph prompt carries the standing rules. Long-form instructions have no delivery path.

Docs-not-needed: not used — this is an issue, not a pull request.

Delivery requirements (Chief, 2026-10-30T19:42Z)

• Files: plugins/workflow/src/service.js (assign() ~line 1155, stepBody() ~line 566-577, start() ~line 1587), plus whatever plugins/workflow/test/*.test.js file fits (a new assign-brief.test.js is fine).
• Red first: a test that assigns a task whose brief is not in the title and asserts the node prompt carries that brief; it must fail on the current main for exactly that reason, and pass after the change. Also one that keeps the title fallback working when no brief is given.
• Do not change the shape of stepBody for other callers beyond the new brief value; start() must keep working (it passes a brief that becomes the title today).
• Same PR: docs/subsystems/workflow.md gains the brief row, and changelog.d/1869-assign-brief.fixed.md.
• plugins/** is T2: the tip needs a PASS (Reviewer) plus green tests-ok.
• On this host do not run the full npm --prefix core test (it hits spawn EAGAIN); run the workflow plugin suite file by file with --test-concurrency=1.
• Reply must end with OUTPUT pr: <n> (or OUTPUT note: … when it stops short).