# Implementation self-check (BLOCKING — before you claim done) Before declaring the change complete, confirm each item below against the ACTUAL diff — not from memory. This is a re-derivation, not a rubber stamp: enumerate the changed files (`git diff --name-only ..HEAD`) and, for the per-file items, write the confirming evidence per file, not one global "✓". If any item fails, fix it or surface the violation — do not claim done on a failing item. - diff-review done: the `Pre-commit diff review sweep` ran over the full diff and its `Coverage:` footer is in your audit sidecar — every changed file named, with each applied rule set carrying its outcome (`clean` or `fixed `). No footer, or entries with no outcome → the sweep is unfinished; do not claim done. - functions: every new/edited function ≤50 effective lines, single purpose — cite the longest function's actual line count, not "all under 50" - conventions: applied the routed pack + project patterns (name which ones) - names & comments: names say what, comments say why; no obvious-restatement comments; no truthful-name violations - verification: ran the actual build/test — paste the exact command line and its real exit code / output tail, never a paraphrased "tests pass" - acceptance: each implemented plan step's `Acceptance:` condition is observably met — cite the RED→GREEN test (or the command output) proving it per step, not one global "acceptance met"; and each `Test case (success|boundary|failure)` the plan declared for this stage has a matching test in the diff (name the test), so declared edge/failure cases are not silently uncovered - mutation check: enumerate every branch this diff adds (`catch`, guard, early return, `else`), plus at least one test it added or changed. For each entry, break what it covers on purpose — delete the branch body, return the wrong value, skip the write — confirm a test FAILS, then restore; cite the branch (or test) and the observed failure per entry, not one global "mutation verified". A branch whose deletion leaves the suite green is untested, not covered — an untested recovery path is indistinguishable from one that cannot fire. "Verified" claimed without this check plus the real command output above is not a verified claim - cleanup: no dead or commented-out code left behind, and no caller-less identifier — list every identifier this diff added or whose last caller it removed, and cite the caller you grepped for each one (or the plan step / non-project-code contract point that justifies keeping it with none). "No new identifiers" is a valid answer; a global "cleaned up" is not Close with a `Self-check coverage:` line naming the files you verified the per-file items against, so the Coverage footer above and this gate reconcile.