Not able to use Zod object as outputType w/ Deno + Supabase Edge Functions

[mulder3010]

Describe the bug

I am triggering a supabase edge function using Agent SDK version "@openai/agents": "^0.0.17".
But, I am not able to use Zod object as outputType.
I receive the following error when creating an agent with a Zod object as outputtype:
Error] Unexpected error: 400 Missing required parameter: 'text.format.type'.

Debug information

I am not able to create and run an agent using outputtype object.
Even from: examples/docs/agents/agentWithAodOutputType.ts

I checked the underlying function verifying the object, it retrieves a false value for isZodObject().

For debugging I looked at
https://github.com/openai/openai-agents-js/blob/main/packages/agents-core/src/agent.ts

and at:
packages/agents-core/src/utils/typeGuards.ts

const CalendarEvent = z.object({
      name: z.string(),
      date: z.string(),
      participants: z.array(z.string()),
    });

function isZodObject(input: unknown): input is ZodObject<any> {
  return (
    typeof input === 'object' &&
    input !== null &&
    '_def' in input &&
    typeof input._def === 'object' &&
    input._def !== null &&
    'typeName' in input._def &&
    input._def.typeName === 'ZodObject'
  );
}

  if (isZodObject(CalendarEvent)) {
      console.log("Expected output schema:", CalendarEvent);
    } else {
      console.log("Invalid output schema for CalendarEvent");
    }

This gave me a true value:

function isZodObject(input: unknown): input is ZodObject<any> {
      return (
        // check #1: instanceof
        input instanceof ZodObject ||
        // check #2: structural fallback
        (typeof input === "object" &&
          input !== null &&
          "_def" in input &&
          typeof (input as any)._def === "object" &&
          (input as any)._def !== null &&
          (input as any)._def.typeName === ZodFirstPartyTypeKind.ZodObject)
      );
    }

Repro steps

Original code:

const extractor = new Agent({
  name: "Calendar extractor",
  instructions: "Extract calendar events from the supplied text.",
  outputType: z.object({
    name: z.string(),
    date: z.string(),
    participants: z.array(z.string()),
  }),
});

  const result = await run(extractor, [
      {
        type: "message",
        role: "user",
        content: "Tomorrow at 3 pm 30/08/2025, meeting with John and Jane",
      },
    ]);

Expected behavior

I would expect a result from the run that equals the inputted output type as a JSON.

What would be your suggestion to get a correct zod output structure?

[seratch]

Which zod version do you use? If you're using 4.x, this SDK is not yet compatible with the major version. Please install v3 by npm i zod@3.

[mulder3010]

Thanks Seratch for your reply. I'am using "zod": "3.25.67", will try it with zod@3.

[seratch]

The version should work, but there may be something extra preventing the zod from working with the Agents SDK. Are you running your code on Deno runtime hosted by Supabase, right? The module resolution could be a bit different from common Node + npm. So, please double-check how modules are installed and used. If you use npm command, running npm ls --all and checking the output may be helpful too. If you use other tools, running something equvalent may help.

[seratch]

Also, if you can provide simple repro steps on local machine, we may be able to check what's going on too.

[mulder3010]

Got it, thank you!
Local Deno, did not have the correct Zod version.