diff --git a/.agents/skills/create-github-pr/SKILL.md b/.agents/skills/create-github-pr/SKILL.md
index 59ab0dade0..885f81cd4d 100644
--- a/.agents/skills/create-github-pr/SKILL.md
+++ b/.agents/skills/create-github-pr/SKILL.md
@@ -245,6 +245,14 @@ EOF
 | `--head, -H`        | Source branch (default: current)           |
 | `--web`             | Open in browser after creation             |
 
+## Labels
+
+Apply exactly one `area:` label and any relevant `topic:` labels. Choose them from
+the `### area:*` and `### topic:*` headings in `REVIEWERS.md`, reading each
+section's description against the files you changed. Do not choose from
+`gh label list`: it contains legacy labels such as `area:gateway` that have no
+reviewer roster, so they request no reviewers.
+
 ## After Creating
 
 The command outputs the PR URL and number.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 3e800debdf..bad1c50886 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -72,7 +72,7 @@ Every pull request must be approved by someone listed in [MAINTAINERS.md](MAINTA
 
 Pull requests that touch the enforcement machinery or reviewer routing — anything under `.github/workflows/`, `.github/actions/`, `MAINTAINERS.md`, `REVIEWERS.md`, `.github/CODEOWNERS`, or the enforcement and reviewer-routing scripts in `tasks/scripts/` — additionally require a code owner's approval, listed in [.github/CODEOWNERS](.github/CODEOWNERS). The status check reads its inputs from `main`, but a workflow triggered by a review runs the pull request's own copy of the workflow file, so GitHub's native code owner requirement is what keeps a change from disabling the gate that would have blocked it.
 
-Use exactly one `area:` label and any relevant `topic:` labels on your pull request. The [reviewer routing workflow](.github/workflows/review-readiness.yml) requests all matching members of [REVIEWERS.md](REVIEWERS.md), excluding the author, when a PR opens ready for review, leaves draft status, or gains or loses an area/topic label. Reviewers do not need repository write access to receive requests or review PRs. Manual reviewer choices and people who have commented or reviewed are preserved. Propose roster membership changes through a reviewed PR.
+Use exactly one `area:` label and any relevant `topic:` labels on your pull request. The valid labels are the `area:*` and `topic:*` headings in [REVIEWERS.md](REVIEWERS.md); that file, not the repository's label list, is the source of truth, and a label without a matching heading routes to no reviewers. The [reviewer routing workflow](.github/workflows/review-readiness.yml) requests all matching members of [REVIEWERS.md](REVIEWERS.md), excluding the author, when a PR opens ready for review, leaves draft status, or gains or loses an area/topic label. Reviewers do not need repository write access to receive requests or review PRs. Manual reviewer choices and people who have commented or reviewed are preserved. Propose roster membership changes through a reviewed PR.
 
 If your pull request has been idle, ask for a reviewer in the pull request or in the CNCF Slack channel rather than waiting.