diff --git a/__tests__/bundle/dispatcherArms.test.ts b/__tests__/bundle/dispatcherArms.test.ts
new file mode 100644
index 00000000..8bdeb0d8
--- /dev/null
+++ b/__tests__/bundle/dispatcherArms.test.ts
@@ -0,0 +1,47 @@
+import type { FakeGithub } from './fakeGithub'
+import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
+
+import { start } from './fakeGithub'
+import { comment, repo, token } from './helpers'
+import { runBundle } from './runBundle'
+
+vi.setConfig({ testTimeout: 30_000 })
+
+// the arms of handleIssueComment itself — the prow-commands input and the per-command error isolation —
+// driven through dist/index.js like the commands in bundle.test.ts
+describe('dist/index.js issue_comment dispatcher', () => {
+  let gh: FakeGithub
+
+  beforeAll(async () => {
+    gh = await start()
+  })
+  afterEach(() => gh.reset())
+  afterAll(() => gh.close())
+
+  function run(body: string, inputs: Record<string, string>) {
+    return runBundle({ eventName: 'issue_comment', payload: comment(body), inputs: { ...token, ...inputs }, apiUrl: gh.url })
+  }
+
+  it.each([
+    ['missing', {}],
+    ['only whitespace', { 'prow-commands': '  \n\t ' }],
+  ])('a prow-commands input that is %s fails the run naming the input, with no api call', async (_name, inputs) => {
+    const result = await run('/hold', inputs)
+
+    expect(result.status, result.stdout).toBe(1)
+    expect(result.errors.some(e => e.includes('please provide a list of space delimited commands / jobs to run'))).toBe(true)
+    expect(gh.requests).toEqual([])
+  })
+
+  it('one failing command does not stop another in the same body: /remove fails, /hold still applies', async () => {
+    gh.route('GET', `${repo}/collaborators/Codertocat`, { status: 404, body: { message: 'Not Found' } })
+    gh.route('GET', `${repo}/labels`, { status: 200, body: [{ name: 'do-not-merge/hold' }] })
+    gh.route('POST', `${repo}/issues/1/labels`, { status: 200, body: [] })
+
+    const result = await run('/remove foo\n/hold', { 'prow-commands': '/remove /hold' })
+
+    expect(result.status, result.stdout).toBe(1)
+    expect(result.errors.some(e => e.includes('commenter is not authorized to remove a label'))).toBe(true)
+    expect(gh.requestsMatching('POST', /\/issues\/1\/labels$/)[0].body).toEqual({ labels: ['do-not-merge/hold'] })
+  })
+})