diff --git a/CLAUDE.md b/CLAUDE.md
index 63af2aa8..dfc68cc2 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -178,6 +178,12 @@ something, not only sessions that touch `documentation/` — which is why it is
      rows — a run can sit several pages earlier. **Scan every page** and match on `head_sha`; with a
      few hundred jobs that is a handful of requests. Guessing the page produced three consecutive
      false "no CI job for this commit" readings in one session.
+  3. **A rerun REPLACES the attempt the `jobs` endpoint shows** (R-1137, measured 2026-10-18): the job
+     keeps its id, `run_attempt` becomes 2, `started_at`, `conclusion` and the log are the rerun's — the
+     red first attempt is gone from `jobs` and its log (controller jobs 1944, 1959: failure mails, now
+     green). **A matched job with `run_attempt` > 1 is not a plain green:** list `actions/tasks` (same
+     paging, match `head_sha`) — one task per attempt, the verdict in `status`, so it reads
+     „failure, then rerun success". The first attempt's log is not reachable by the API.
 
   An unchecked green is an assumption, not an observation — and so is a green read off a field the
   API never populates.