Every commit in this checkout now builds ./cmd/abcd twice, once in .githooks/pre-commit for the sources refresh and once in commit-msg for the outbound lint (about 13 s on a cold build cache), where one shared build per commit would do; and in a linked worktree the pre-commit prints a sources skip line on every commit beside the existing linked-worktree notice (review2-sources 4 and 7).

Every commit in this checkout now builds ./cmd/abcd twice, once in .githooks/pre-commit for the sources refresh and once in commit-msg for the outbound lint (about 13 s on a cold build cache), where one shared build per commit would do; and in a linked worktree the pre-commit prints a sources skip line on every commit beside the existing linked-worktree notice (review2-sources 4 and 7).

Remedy grounds (2026-09-29)

• The deferral's measurement answers the first half: sharing one binary would save about half a second at the cost of a trust hand-off between two hooks, so the remedy keeps both builds.
• Hook behaviour already has test homes (internal/core/banlist/hook_test.go, internal/adapter/scanner/hook_layers_test.go). Rejected: one shared build per commit, for the trust reason above.