prompt parameter does not work when being passed via an Agent

[MarkMurphy]

Describe the bug

I'm passing the id to a prompt I've created on the OpenAI platform however it doesn't seem that the agent is using it. I tested it with a simple prompt that states the Agents name is Joe. When I then ask the agent its name it doesn't seem to be using the prompt, here's example of the input/output:

User

What is your name?

Assistant

I'm ChatGPT — an AI assistant.

---

Here's a simplified version of my code to illustrate how I'm using it:

const agent = new Agent({
  name: 'Agent',
  model: 'gpt-5',
  prompt: {
    promptId: 'pmpt_67dd91dbefbc8195aeab57120734d05809a1f2314c1284c6',
  },
})

const result = await run(agent, 'What is your name?')

Assistant

I'm ChatGPT — an AI assistant.

• Agents SDK version: v0.1.8
• Runtime environment: Node.js 22.16.0

When I tried the same thing using the responses API directly, it works just fine. e.g.

const response = await openai.responses.create({
  model: 'gpt-5',
  input: 'What is your name?',
  prompt: {
    id: 'pmpt_67dd91dbefbc8195aeab57120734d05809a1f2314c1284c6',
  },
})

In case it's of any significance, there's an inconsistency in the properties/field names that the prompt parameter takes when calling new Agent({ ... }) vs. openai.responses.create({ ... }) as you can see by comparing the examples above (i.e. id vs. promptId).

[seratch]

Thank you so much for reporting this issue. I've submitted #559 for fixing it and we'll resolve it in the next release.