diff --git a/__tests__/bundle/collaborationArms.test.ts b/__tests__/bundle/collaborationArms.test.ts
new file mode 100644
index 0000000..f0201c0
--- /dev/null
+++ b/__tests__/bundle/collaborationArms.test.ts
@@ -0,0 +1,85 @@
+import type { FakeGithub } from './fakeGithub'
+import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
+
+import { start } from './fakeGithub'
+import { comment, helpersFor, repo, token } from './helpers'
+import { runBundle } from './runBundle'
+
+vi.setConfig({ testTimeout: 30_000 })
+
+// the arms of /reopen and /retitle that collaborationCommands.test.ts leaves out, driven through dist/index.js:
+// a collaborator read that fails with something other than 404 is a warning and a silent no-op (checkCollaborator
+// swallows it), and a refused write fails the run with the command's own cause
+describe('dist/index.js /reopen and /retitle failure arms', () => {
+  const collaboratorPath = `${repo}/collaborators/Codertocat`
+  const issuePath = `${repo}/issues/1`
+  const collaboratorRead = `GET ${collaboratorPath}`
+  const issueWrite = `PATCH ${issuePath}`
+  const collaboratorWarning = '::warning::encountered unexpected error checking collaborator status: status=500'
+  let gh: FakeGithub
+  const { calls } = helpersFor(() => gh)
+
+  beforeAll(async () => {
+    gh = await start()
+  })
+  afterEach(() => gh.reset())
+  afterAll(() => gh.close())
+
+  async function run(body: string, command: string, author?: string) {
+    return runBundle({
+      eventName: 'issue_comment',
+      payload: comment(body, author),
+      inputs: { ...token, 'prow-commands': command },
+      apiUrl: gh.url,
+    })
+  }
+
+  describe('/reopen', () => {
+    it('by a non-author whose collaborator read returns 500 warns and reopens nothing', async () => {
+      gh.route('GET', collaboratorPath, { status: 500, body: { message: 'boom' } })
+
+      const result = await run('/reopen', '/reopen', 'some-author')
+
+      expect(result.status, result.stdout).toBe(0)
+      expect(result.errors).toEqual([])
+      expect(result.stdout).toContain(collaboratorWarning)
+      expect(calls()).toEqual([collaboratorRead])
+    })
+
+    it('by the author fails the action when the reopen write is refused', async () => {
+      gh.route('PATCH', issuePath, { status: 500, body: { message: 'boom' } })
+
+      const result = await run('/reopen', '/reopen')
+
+      expect(result.status, result.stdout).toBe(1)
+      expect(result.errors.some(e => e.includes('could not open issue'))).toBe(true)
+      expect(calls()).toEqual([issueWrite])
+      expect(gh.requestsMatching('PATCH', /\/issues\/1$/)[0].body).toEqual({ state: 'open' })
+    })
+  })
+
+  describe('/retitle', () => {
+    it('whose collaborator read returns 500 warns and retitles nothing', async () => {
+      gh.route('GET', collaboratorPath, { status: 500, body: { message: 'boom' } })
+
+      const result = await run('/retitle Sneaky', '/retitle')
+
+      expect(result.status, result.stdout).toBe(0)
+      expect(result.errors).toEqual([])
+      expect(result.stdout).toContain(collaboratorWarning)
+      expect(calls()).toEqual([collaboratorRead])
+    })
+
+    it('by a collaborator fails the action when the title write is refused', async () => {
+      gh.route('GET', collaboratorPath, { status: 204 })
+      gh.route('PATCH', issuePath, { status: 500, body: { message: 'boom' } })
+
+      const result = await run('/retitle A better title', '/retitle')
+
+      expect(result.status, result.stdout).toBe(1)
+      expect(result.errors.some(e => e.includes('could not update issue'))).toBe(true)
+      expect(calls()).toEqual([collaboratorRead, issueWrite])
+      expect(gh.requestsMatching('PATCH', /\/issues\/1$/)[0].body).toEqual({ title: 'A better title' })
+    })
+  })
+})