per-lane PM job descriptions move from seat-post prose into versioned skill references — seat posts shrink to pure state #9871

Maintainer ruling (2026-08-19, PM chat, verbatim): 「所以我认为每一种项目经理的岗位说明应该进skills,类似分诊」 — following their observation that seat posts keep growing and asking whether every PM re-reads them (token economics). Filed and graded by the skills seat (own-lane exception), session session_01AeA3nU1B5Q2pgxqxgUrexd.

The gap this closes

The protocol already mandates 「座位行为全部版本化在 git,升级走技能 PR」 and the triage seat complies — its entire duty section lives in SKILL.md. Execution seats do not: each seat post carries 范围 and 常设承诺 sections that are job-description material living in an issue body, hand-copied forward at every takeover ("survives exactly as long as each successor remembers to copy it" — the same fragility the foreign-gate parking card documented for a different payload). Behavior drift there is invisible to diffs, ungoverned, and re-paid in tokens at every takeover.

Scope

1. One reference file per lane: .claude/skills/pm-dispatch/references/lanes/<lane>.md — content migrated from the live seat posts' 范围 + 常设承诺 + lane-specific judgment notes. The spec lane's 席内分派参考 (already in SKILL.md) is the in-house precedent for lane-specific judgment text living in the skill; whether it relocates into its lane file or stays put is the dev's call — one home, no duplication either way.
2. Seat-post template shrinks from six sections to four (当前 PM / 继承台账 / 热文件串行队 / 说明): update the 座位贴协议 section in SKILL.md and references/seat-post-protocol.md. 范围 and 常设承诺 leave the template; a lane's post points at its lane file.
3. Ratchet: every new lane file gets a CEILINGS entry in check-skill-line-ratchet.mjs at its landed line count (the AGENTS.md-entry precedent — set from the settled file, shrink-only).
4. Migration of the live seat posts' prose into the files is seat work after the PR lands (each sitting PM trims their own post at next flush; vacant lanes' posts trimmed by whoever takes them over) — the PR must not rewrite seat-post bodies itself.

Sequencing (binding)

After the lane-consolidation card lands (its table PR + label migration) — so this writes SIX lane files, not nine. SKILL.md hot-file chain applies.

.claude/skills/pm-dispatch/** ⇒ claude-fable-5 mandatory; governed ⇒ draft PR, maintainer merge. Graded pm:queue, M.