diff --git a/.github/workflows/pull-labeler.yml b/.github/workflows/pull-labeler.yml
index e2c3e42fb1..8ee744a552 100644
--- a/.github/workflows/pull-labeler.yml
+++ b/.github/workflows/pull-labeler.yml
@@ -43,5 +43,6 @@ jobs:
       - run: node ./tools/ci-tools.ts set-pr-labels
         env:
           PR_TITLE: ${{ github.event.pull_request.title }}
+          PR_TITLE_BEFORE: ${{ github.event.changes.title.from }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
           GITHUB_TOKEN: ${{ github.token }}
diff --git a/tools/ci-tools.ts b/tools/ci-tools.ts
index b872c35187..8c3dcedf6a 100644
--- a/tools/ci-tools.ts
+++ b/tools/ci-tools.ts
@@ -20,9 +20,12 @@ type CommitType = typeof allowedTypes[number];
 const allowedTypesList = allowedTypes.join(', ');
 const titlePattern = new RegExp(`^(${allowedTypes.join('|')})(\\([\\w/.-]+\\))?(!)?: .+$`);
 
-function parsePrTitle(title: string): {type: CommitType; breaking: boolean} | null {
+function parsePrTitle(title: string): {type: CommitType, scope: string, breaking: boolean} | null {
   const match = titlePattern.exec(title);
-  return match ? {type: match[1] as CommitType, breaking: Boolean(match[3])} : null;
+  if (!match) return null;
+  // Keep the first segment, so "webhook/discord" matches "webhook".
+  const scope = match[2] ? match[2].slice(1, -1).toLowerCase().split('/')[0] : '';
+  return {type: match[1] as CommitType, scope, breaking: Boolean(match[3])};
 }
 
 const breakingLabel = 'pr/breaking';
@@ -36,21 +39,44 @@ const typeLabels: Partial<Record<CommitType, string>> = {
   test: 'type/testing',
 };
 
-// Non-type labels, only added, never auto-removed, so manual labeling is not clobbered.
+// Non-type labels, removed only when the previous title implied them.
 const extraLabels: Partial<Record<CommitType, string>> = {
   chore: 'skip-changelog',
   ci: 'skip-changelog',
   build: 'topic/build',
 };
 
+// Scopes whose label differs from "topic/<scope>".
+const scopeAliases: Record<string, string> = {
+  actions: 'topic/gitea-actions',
+  auth: 'topic/authentication',
+  issue: 'topic/issues',
+  markup: 'topic/content-rendering',
+  oauth: 'topic/authentication',
+  oauth2: 'topic/authentication',
+  pull: 'topic/pr',
+  pulls: 'topic/pr',
+  webhook: 'topic/webhooks',
+};
+
+function labelForScope(scope: string): string | undefined {
+  if (!scope) return undefined;
+  return scopeAliases[scope] ?? `topic/${scope}`;
+}
+
 // Labels this tool may remove when the title no longer implies them.
 const removableLabels = [...Object.values(typeLabels), breakingLabel];
 
 function labelsForPrTitle(title: string): string[] {
   const parsed = parsePrTitle(title);
   if (!parsed) return [];
-  return [typeLabels[parsed.type], extraLabels[parsed.type], parsed.breaking ? breakingLabel : undefined]
-    .filter((label): label is string => label !== undefined);
+  const labels = [
+    typeLabels[parsed.type],
+    extraLabels[parsed.type],
+    labelForScope(parsed.scope),
+    parsed.breaking ? breakingLabel : undefined,
+  ].filter((label): label is string => label !== undefined);
+  return [...new Set(labels)];
 }
 
 // Command: validate PR_TITLE against the allowed Conventional Commits format.
@@ -76,7 +102,7 @@ async function setPrLabels(): Promise<void> {
 
   const labelsUrl = `https://api.github.com/repos/${env.GITHUB_REPOSITORY}/issues/${env.PR_NUMBER}/labels`;
 
-  async function request(url: string, method = 'GET', body?: unknown): Promise<Response> {
+  async function request(url: string, method = 'GET', body?: unknown, ignoreStatus?: number): Promise<Response> {
     const response = await fetch(url, {
       method,
       headers: {
@@ -87,25 +113,46 @@ async function setPrLabels(): Promise<void> {
       },
       body: body ? JSON.stringify(body) : undefined,
     });
-    if (!response.ok) {
+    if (!response.ok && response.status !== ignoreStatus) {
       throw new Error(`GitHub API ${method} ${url} failed (${response.status}): ${await response.text()}`);
     }
     return response;
   }
 
-  const desired = labelsForPrTitle(env.PR_TITLE);
-  const response = await request(`${labelsUrl}?per_page=100`);
-  const current = ((await response.json()) as Array<{name: string}>).map((label) => label.name);
+  async function fetchNames(url: string): Promise<string[]> {
+    const names = [];
+    for (let page = 1; page <= 10; page++) {
+      const labels = (await (await request(`${url}?per_page=100&page=${page}`)).json()) as Array<{name: string}>;
+      names.push(...labels.map((label) => label.name));
+      if (labels.length < 100) break;
+    }
+    return names;
+  }
 
+  // Labels the repo does not have are dropped instead of failing the job.
+  const candidates = labelsForPrTitle(env.PR_TITLE);
+  const repoLabelsUrl = `https://api.github.com/repos/${env.GITHUB_REPOSITORY}/labels`;
+  const [current, existing]: string[][] = await Promise.all([
+    fetchNames(labelsUrl),
+    candidates.length ? fetchNames(repoLabelsUrl) : [],
+  ]);
+  const desired = candidates.filter((name) => {
+    if (existing.includes(name)) return true;
+    console.info(`Skipping label not present on the repo: ${name}`);
+    return false;
+  });
+
+  const stale = new Set([...removableLabels, ...labelsForPrTitle(env.PR_TITLE_BEFORE ?? '')]);
   const toAdd = desired.filter((name) => !current.includes(name));
-  const toRemove = removableLabels.filter((name) => current.includes(name) && !desired.includes(name));
+  const toRemove = current.filter((name) => stale.has(name) && !desired.includes(name));
 
   if (toAdd.length) {
     await request(labelsUrl, 'POST', {labels: toAdd});
     console.info(`Added labels: ${toAdd.join(', ')}`);
   }
   for (const name of toRemove) {
-    await request(`${labelsUrl}/${encodeURIComponent(name)}`, 'DELETE');
+    // 404 means the label is already gone.
+    await request(`${labelsUrl}/${encodeURIComponent(name)}`, 'DELETE', undefined, 404);
     console.info(`Removed label: ${name}`);
   }
   if (!toAdd.length && !toRemove.length) {