diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index 97c7f3c..cf6b56b 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -2,7 +2,7 @@
 <!-- 1–3 sentences. What does this PR do and why? -->
 
 ## Related
-<!-- Closes #123 / Ref tracebloc/other-repo#456 -->
+<!-- Same repo: Closes #123 · Cross-repo: Fixes tracebloc/backend#456 (owner-qualified — a bare backend#456 closes nothing). PRs land on develop, not the default branch, so confirm the issue actually closed. -->
 
 ## Type of change
 - [ ] Feature
@@ -19,3 +19,4 @@
 - [ ] `go build ./...`, `go vet`, and the Lint job's checks pass locally
 - [ ] Terminal output follows [STYLE.md](../STYLE.md) — Printer tones (no hardcoded colour/emoji), "secure environment" not "workspace"; `bash scripts/check-style.sh` passes
 - [ ] No secrets / credentials in the diff
+- [ ] Cross-repo issues use `Fixes tracebloc/<repo>#N` — a bare `repo#N` closes nothing
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b1374a6..15123e4 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -55,7 +55,7 @@ This repo follows the same conventions as the rest of the tracebloc org:
   fix(#150): handle empty kubeconfig gracefully
   ```
 
-- **PR body** should include a `Closes #N` line (on its own line) for any ticket the PR fully resolves. GitHub auto-closes the issue on merge. The `feat(#N):` convention in the title is for kanban tracking; `Closes #N` in the body is what triggers auto-close.
+- **PR body** should include a `Closes #N` line (on its own line) for any ticket the PR fully resolves. The `feat(#N):` convention in the title is for kanban tracking; the body line is what links the issue. Owner-qualify anything in another repo — `Fixes tracebloc/backend#123` — because a bare `backend#123` only cross-references and closes nothing. And since GitHub fires closing keywords only on merges into the default branch (`main`), a PR merged to `develop` won't auto-close on its own: confirm the ticket, and close it by hand if needed.
 
 - **One PR per ticket** when practical. Roll-up sync PRs (`Sync develop → main for vX.Y.Z release`) are an exception.