diff --git a/CHANGELOG.md b/CHANGELOG.md
index a87dcfc..60d2a46 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,30 @@
+## the decoy sweep — can this gate be fooled by a label? (2026-09-01, R-421) — NOT A RELEASE
+
+**No product code, no version bump, no image, no golden.** A scripts change is not a release.
+
+Four times in one week a gate turned out to match a NAME instead of the thing it named — R-410 (a
+`mkdir` turned the release gate green), R-400 (seven debug controls answering nothing), R-378 (a
+status word inside a sentence), R-419 (a phrase inside prose, including prose saying the marker was
+absent). **All four found by accident.** The gates enforce everything else here and were the one part
+nothing had checked.
+
+**All 29 gate scripts read and decoyed. 16 were fooled.** 10 fixed here, 4 left with rows
+(R-422..R-425), 6 could not be given a plausible decoy and are named (R-426 group d).
+
+**The largest single cause was mundane:** eight gates set their SCOPE with `os.listdir` (one level).
+Green and correct today; blind the moment anyone adds `templates/partials/`. `mojibake` and
+`docker-v` already used `os.walk`, caught the identical planted file, and are the control that
+proves the cause was the listing rather than the decoy.
+
+Full survey table, and the five decoys withdrawn as illegitimate (mine, named):
+`documentation/audits/AUDIT-gate-decoys-2026-09-01.md`.
+
+**In this repo:** no gate changed, and that is the result. `release-complete` was decoyed and is
+SOUND — the sweep's attempt (a non-version heading on top of `CHANGELOG.md`) was WITHDRAWN as
+illegitimate, because `HEAD_RE.search` scans the whole file and still names `v0.130.0`. The three
+shared gates are covered from `felhom.eu`; the remaining two are named in the decoy-coverage
+exemption list (R-426) as UNTESTED, not as sound.
+
 ## v0.130.0 — the agent was the one leaking connections onto the off-site box (2026-08-20, R-344)
 
 > **RELEASED 2026-08-20**, on the operator's word, after the fix was proved on both boxes.
diff --git a/CLAUDE.md b/CLAUDE.md
index dbff38c..742f90d 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -101,3 +101,11 @@ the mechanism are exempt.
 - **Confirm your own last push's CI run went green, by run ID** — CI mails on failure, which is a PUSH
   signal; this is the PULL check that catches a lost or unread mail. An unchecked green is an
   assumption, not an observation.
+
+**A gate ships with a decoy test that has been seen to fail (R-421).** A decoy is the LABEL without
+the FACT — a directory with the right name and no bake log, a note whose prose mentions the marker it
+lacks. `scripts/decoy_coverage_gate.py` refuses a new gate that has neither a decoy nor a named
+exemption carrying its row. The four shapes, the 2026-09-01 sweep that fooled 16 of 29 gates, and the
+decoys withdrawn as illegitimate: `documentation/audits/AUDIT-gate-decoys-2026-09-01.md` and
+`felhom-controller/.claude/rules/gates.md`. **Scope is a fact too** — prefer `os.walk` over
+`os.listdir`, and a glob over a hand-maintained list.