diff --git a/__tests__/bundle/labelSyncCatalog.test.ts b/__tests__/bundle/labelSyncCatalog.test.ts
new file mode 100644
index 00000000..703e0670
--- /dev/null
+++ b/__tests__/bundle/labelSyncCatalog.test.ts
@@ -0,0 +1,98 @@
+import type { FakeGithub } from './fakeGithub'
+import { Buffer } from 'node:buffer'
+import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
+
+import labelFileContents from '../fixtures/labels/labelFileContentsResp.json'
+import { start } from './fakeGithub'
+import { configReads, helpersFor, repo, token } from './helpers'
+import { runBundle } from './runBundle'
+
+vi.setConfig({ testTimeout: 30_000 })
+
+const labelsRead = `GET ${repo}/labels?per_page=100`
+
+function yamlFile(text: string) {
+  const file = structuredClone(labelFileContents)
+  file.content = Buffer.from(text).toString('base64')
+  return file
+}
+
+// the parts of the label catalog that bundle.test.ts' label-sync cases (a `kind` section only) never compose:
+// a section outside the command registry, the require_matching_label missing labels and the dedup of a
+// missing label two rules spell differently
+describe('dist/index.js label-sync catalog', () => {
+  let gh: FakeGithub
+  const { expectRequests } = helpersFor(() => gh)
+
+  beforeAll(async () => {
+    gh = await start()
+  })
+  afterEach(() => gh.reset())
+  afterAll(() => gh.close())
+
+  const builtins = [
+    'approved',
+    'do-not-merge/hold',
+    'good first issue',
+    'help wanted',
+    'hold',
+    'lgtm',
+    'lifecycle/frozen',
+    'lifecycle/rotten',
+    'lifecycle/stale',
+    'ok-to-test',
+    'stage/alpha',
+    'stage/beta',
+    'stage/stable',
+    'status/approved-for-milestone',
+    'status/in-progress',
+    'status/in-review',
+  ]
+
+  it('creates a custom section as <key>/<value>, one needs-* label per distinct missing_label, in sorted order', async () => {
+    const config = yamlFile([
+      'labels:',
+      '  kind: [bug]',
+      '  team:',
+      '    - name: docs',
+      '      color: 0E8A16',
+      '      description: Owned by the docs team',
+      'require_matching_label:',
+      '  - regexp: ^kind/',
+      '    missing_label: needs-kind',
+      '    issues: true',
+      '  - regexp: ^kind/',
+      '    missing_label: Needs-Kind',
+      '    prs: true',
+      '',
+    ].join('\n'))
+    gh.route('GET', '/repos/Codertocat/.project/contents/prow.yaml', { status: 200, body: config })
+    gh.route('GET', `${repo}/labels`, { status: 200, body: [] })
+    gh.route('POST', `${repo}/labels`, { status: 201, body: {} })
+
+    const result = await runBundle({
+      eventName: 'workflow_dispatch',
+      payload: {},
+      inputs: { ...token, jobs: 'label-sync' },
+      apiUrl: gh.url,
+    })
+
+    expect(result.status, result.stdout).toBe(0)
+    expect(result.errors).toEqual([])
+    const desired = [...builtins, 'kind/bug', 'needs-kind', 'team/docs'].sort((a, b) => a.localeCompare(b))
+    const posts = gh.requestsMatching('POST', /\/labels$/)
+    expect(posts.map(p => (p.body as { name: string }).name)).toEqual(desired)
+    // the configuration's color is lowercased; a needs-* label gets the catalog's default color and nothing else
+    expect(posts.find(p => (p.body as { name: string }).name === 'team/docs')!.body).toEqual({
+      name: 'team/docs',
+      color: '0e8a16',
+      description: 'Owned by the docs team',
+    })
+    expect(posts.find(p => (p.body as { name: string }).name === 'needs-kind')!.body).toEqual({ name: 'needs-kind', color: 'ededed' })
+    expect(posts.find(p => (p.body as { name: string }).name === 'kind/bug')!.body).toEqual({ name: 'kind/bug' })
+    expect(result.stdout).toContain(`label-sync: created ${desired.length} [${desired.join(', ')}], updated 0 [], unchanged 0, failed 0`)
+    expect(gh.requestsMatching('PATCH', /./)).toEqual([])
+    expect(gh.requestsMatching('DELETE', /./)).toEqual([])
+    expectRequests([...configReads({ org: '.project' }), labelsRead], desired.map(() => `POST ${repo}/labels`))
+  })
+})