[finding] REST update-branch is a PM-usable merge-main route (full SHA required; 422 when the base has not moved); job-log download is proxy-refused, annotations suffice

[claude]

Platform-fact reading from the domain:devx execution seat (session session_01LAwHpn4uVuf4N1geBcD5i3), for the references/platform-readings.md / rest-channel.md fact tables — filed as a finding for the skills seat to grade, per the shift-change discipline. Measured 2026-09-03, twice each:

• PUT /repos/{o}/{r}/pulls/{n}/update-branch (REST, app token through the proxy) works from a PM seat and is the zero-file-write way to merge origin/main into a dev's PR head (a real merge commit, no rewrite): 202 "Updating pull request branch." on PRs chore(lint): delete inert eslint-disable family comments in package sources #14801, fix(lint): descend into conditional then/otherwise when building the _validations universe #14820, test(scripts): pin a battery roster floor on 40 more scripts/** self-tests #14851, fix(gates): answer PREREQUISITE NOT MET with the frame's exit code in the last three i18n gates #14856, fix(scripts): give 24 more self-tests a verdict handshake at their dispatch (#13798 batch 2) #14853, test(scripts): pin a battery roster floor on 18 class-1 scripts/** self-tests (#13799 batch 1b) #14872.
• Its expected_head_sha must be the full 40-char SHA — a short SHA answers 422 "expected head sha didn't match current head ref" (PRs chore(lint): delete inert eslint-disable family comments in package sources #14801/fix(lint): descend into conditional then/otherwise when building the _validations universe #14820, 04:25Z).
• When the base has not moved since the branch was cut it answers 422 "There are no new commits on the base branch" (PR test(scripts): pin a battery roster floor on 18 class-1 scripts/** self-tests (#13799 batch 1b) #14872, 07:3xZ) — that is "nothing to do", not a failure, and it means a PR-side re-trigger by this route is unavailable until main moves.
• Job-log download (GET /actions/jobs/{id}/logs) is refused by the egress proxy (CONNECT tunnel failed, response 403); the check-run annotations endpoint still carries the exit code and failing command, which was enough to attribute every red this shift to its shard/package.

Zero code change proposed; the ask is one or two lines in the fact tables.

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[os-zhuang]

分诊路由(本评论来自分诊座位)· R+150 · date -u 实测 2026-09-04T19:38:57Z

domain:skills · finding + documentation · priority:p3。

落点实测(git ls-files,同一次调用):

.claude/skills/pm-dispatch/references/platform-readings.md
.claude/skills/pm-dispatch/references/rest-channel.md

⇒ 两份事实表都在 .claude/skills/** ⇒ 车道表归 skills,且是受管面(GOVERNED_SURFACES 的 claude-tree 肢)⇒ draft PR + 人工合并。

p3 判据:零代码改动,交付物是事实表里的一两行;它省的是下一个 PM 席重新测一遍 REST 通道的时间(卡上四条读数每条都测了两次)。真实但小 ⇒ p3。

⭐ 卡上四条读数里,第三条对 PM 席最要紧、也最容易被读反:base 未移动时 update-branch 答 422「There are no new commits on the base branch」—— 那是「无事可做」,不是失败;写进事实表时请把这句判读一起写进去,否则下一个席位会把它当红。

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[claude]

First-touch grading by the lane — priority:p3 stands, pm:queue, folded into the platform-readings member of the PM corpus family (skills seat, session session_019RfFHiRCSs3JXLK4cwcfox, os-steve, 2026-09-04T21:1xZ).

The four readings (REST update-branch as the zero-file-write merge-main route with a full 40-char expected_head_sha; 422 "no new commits on the base branch" read as nothing-to-do, not failure; job-log download refused by the egress proxy while check-run annotations carry the exit code and command) land as rows in references/platform-readings.md / rest-channel.md when that member rewrites both files rules-only (net shrink, no ceiling raise), together with #15121, #15525 and #15481. That member's PR carries Fixes for this card.

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[claude]

Claim: PM loop round 5 — folded into #15379 member 3 (the rules-only rewrite of the readings ledger and its siblings); this card's reading lands as fact lines (REST update-branch as a PM-usable merge-main route, full SHA required, 422 when the base has not moved; job-log download proxy-refused, annotations suffice)
Session: session_019RfFHiRCSs3JXLK4cwcfox
Branch: claude/issue-15379-readings-lanes-rules-only (the family branch — a member card has no branch of its own by design)
Worktree: objectstack-issue-15379-m3
Domain: domain:skills
File surface: .claude/skills/pm-dispatch/references/rest-channel.md (write side) + platform-readings.md — one to three fact lines, paid for inside the member's net shrink; no ceiling raise
Container & model: L (the family flight), mode:subagent, model: opus (tier per the chain-head claim)
Clause-②: no
Serial constraints cleared: in the chain-head claim on #15379 (member 3, 2026-09-05T00:1xZ); the member's draft PR carries Fixes #14928 and lands governed (draft, in-seat review, os-zhuang + hotlong, human merge).

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