gate-proposal: retro #2001 repair 8: A Claude-Session commit-message trailer was added a second time within one PR, on a commit made directly by the orchestrating session rather than a dispatched branch-plan-task

[tvna]

Criterion	Interpretation	Planned ops	Proof method	Residual risk
A Claude-Session commit-message trailer was added a second time within one PR, on a commit made directly by the orchestrating session rather than a dispatched branch-plan-task	PR #1984's history was rewritten twice for the same underlying defect class: once at Task 1's own merge-back (caught correctly by skills/executing-a-branch-plan/scripts/gitapex_check_task_commit_provenance.py, which is scoped by design to a dispatched task's own BASE..HEAD range at Step 6, per that script's own docstring), and a second time later in the same PR's cycle when the orchestrating session itself authored a commit directly (outside any dispatched task's worktree) that again carried a Claude-Session trailer -- undetected by any deterministic gate until caught by direct human/session review and repaired via a second git commit-tree rewrite. Open issue #1773 (Commit-message AI-provenance marker not caught pre-commit) already proposes moving this exact detection to commit time via a pre-commit hook, and its own body already discloses a third prior recurrence (issue #1998) whose commit fell outside executing-a-branch-plan's own task-commit path -- the same shape as this PR's own second occurrence. A git pre-commit hook (via .git/hooks or core.hooksPath) is shared across every worktree of one repository, so installing the fix #1773 already proposes would cover a directly-session-authored commit the same way it covers a dispatched task's own commit.	See #1773's own Planned ops (a pre-commit hook running the same AI-provenance-marker scan gitapex_check_task_commit_provenance.py already applies at merge-back time, so a flagged commit message is rejected at authoring time regardless of whether it originates inside a dispatched task's worktree or the main thread).	implementing PR adds the check plus a regression test; confirm it fails against a reintroduced instance of the original defect, then passes	None beyond what #1773 already discloses; this is this defect's 4th disclosed recurrence.

Refs #2001

Dedup-sweep: 127 open gate-proposal issues at 2026-09-14T03:59:11Z; verdict DUPLICATE-OF #1773