vitest-dev/vitest · error · Error

Test runner doesn't support test annotations.

Error message

Test runner doesn't support test annotations.

What it means

Calling `context.annotate()` requires the active test runner to implement `runner.onTestAnnotate` (context.ts:210-211). This is checked at annotation time. If the runner in use (e.g. a custom or minimal runner) does not provide this callback, annotations are unsupported and the error is thrown after the annotation artifact is recorded.

Source

Thrown at packages/vitest/src/runtime/runner/context.ts:211

    }

    const annotation: TestAnnotation = {
      message,
      type: typeof type === 'object' || type === undefined ? 'notice' : type,
    }
    const annotationAttachment = typeof type === 'object' ? type : attachment

    if (annotationAttachment) {
      annotation.attachment = annotationAttachment

      manageArtifactAttachment(annotation.attachment)
    }

    return recordAsyncOperation(
      test,
      recordArtifact(test, { type: 'internal:annotation', annotation }).then(async ({ annotation }) => {
        if (!runner.onTestAnnotate) {
          throw new Error(`Test runner doesn't support test annotations.`)
        }

        await finishSendTasksUpdate(runner)

        const resolvedAnnotation = await runner.onTestAnnotate(test, annotation)
        test.annotations.push(resolvedAnnotation)
        return resolvedAnnotation
      }),
    )
  }) as TestContext['annotate']

  context.onTestFailed = (handler, timeout) => {
    test.onFailed ||= []
    test.onFailed.push(
      withTimeout(
        handler,
        timeout ?? runner.config.hookTimeout,
        true,

View on GitHub (pinned to d568f8ce37)

Solutions

  1. Implement `onTestAnnotate` on your custom `VitestRunner` subclass.
  2. Use the built-in Vitest runners (e.g. the default test runner) which support annotations.
  3. Avoid calling `annotate()` when running under a runner known to lack annotation support.

Example fix

// before: custom runner without onTestAnnotate
class MyRunner extends VitestRunner {
  // ... no onTestAnnotate
}
// after
class MyRunner extends VitestRunner {
  onTestAnnotate(test, annotation) {
    // forward annotation to reporter/store
    return annotation
  }
}
Defensive patterns

Strategy: type-guard

Validate before calling

function runnerSupportsAnnotations(runner: unknown): runner is { onTestAnnotate: Function } {
  return typeof (runner as any)?.onTestAnnotate === 'function'
}
if (runnerSupportsAnnotations(getRunner())) {
  context.annotate('note')
}

Type guard

function runnerSupportsAnnotations(runner: unknown): runner is { onTestAnnotate: Function } {
  return typeof (runner as any)?.onTestAnnotate === 'function'
}

Try / catch

try {
  await context.annotate('note')
} catch (e) {
  if (e instanceof Error && /doesn't support test annotations/.test(e.message)) {
    // annotations unsupported in this runner; degrade gracefully
  } else throw e
}

Prevention

When it happens

Trigger: Using a custom `VitestRunner` that does not define `onTestAnnotate`; calling `context.annotate()` under a runner profile (e.g. some browser or benchmark contexts) that omits annotation support.

Common situations: Building a custom runner for specialized environments; using Vitest APIs under a reduced-capability runner; upgrading Vitest and using annotate with an older custom runner.

Related errors

AI-assisted analysis of vitest-dev/vitest@d568f8ce37 (2026-08-03). Data as JSON: /data/errors/ddb02d47e6ee34a1.json. Report an issue: GitHub.