vercel/ai · error · Error

No prompt was provided and the renderer does not support pro

Error message

No prompt was provided and the renderer does not support prompt input.

What it means

AgentTUIRunner.run needs a prompt to execute a turn. If no prompt argument was given, it falls back to the renderer's readPrompt() for interactive input; if the renderer has no readPrompt support either, it throws. If a turn already ran (hasRunTurn), it returns silently instead of throwing.

Source

Thrown at packages/tui/src/agent-tui-runner.ts:130

  async run() {
    const title = this.title;
    const messages: UIMessage[] = [];
    let nextMessageIndex = 0;
    const generateMessageId = () => `message-${++nextMessageIndex}`;
    let prompt: string | undefined;
    let hasRunTurn = false;
    let streamWithoutPrompt = false;

    while (true) {
      if (!streamWithoutPrompt) {
        if (prompt == null) {
          if (!this.renderer.readPrompt) {
            if (hasRunTurn) {
              return;
            }

            throw new Error(
              'No prompt was provided and the renderer does not support prompt input.',
            );
          }

          try {
            prompt = await this.renderer.readPrompt({ title });
          } catch (error) {
            if (isInterruptedError(error)) {
              return;
            }

            throw error;
          }

          if (prompt == null) {
            return;
          }
        }

View on GitHub (pinned to 69428b1f8b)

Solutions

Pass a prompt string to run().
Use a renderer that implements readPrompt for interactive input.
Check this.renderer.readPrompt support before running without a prompt.
If input comes from elsewhere, supply it explicitly rather than relying on the renderer.

Example fix

// before
await runner.run();
// after
await runner.run({ prompt: 'fix the failing test' });

Defensive patterns

Strategy: validation

Validate before calling

if (prompt == null && !renderer.readPrompt) {
  throw new Error('Provide a prompt or use a renderer that implements readPrompt.');
}

Type guard

null

Try / catch

try {
  await runner.run(opts);
} catch (error) {
  if (error.message.includes('does not support prompt input')) {
    await runner.run({ ...opts, prompt: fallbackPrompt });
  } else throw error;
}

Prevention

Always pass an initial prompt in non-interactive contexts.
Verify renderer capabilities before run().
Implement readPrompt in custom renderers.
Skip interactive renderers in tests/scripts.

When it happens

Trigger: Calling run() without a prompt on the first turn while the configured renderer does not implement readPrompt (non-interactive/programmatic renderer).

Common situations: Driving the agent programmatically (tests, scripts) with a headless renderer; forgetting to pass the initial prompt; using a custom renderer that lacks readPrompt.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of vercel/ai@69428b1f8b (2026-08-30). Data as JSON: /api/errors/c1b28a6c40a6d2dc. Report an issue: GitHub.