Structured Output

Force the agent to return a specific JSON shape. Invalid responses are automatically retried.

Basic Usage

Agent.builder()
  .setOutputSchema({
    fields: {
      summary:  { type: "string",  required: true },
      success:  { type: "boolean", required: true },
      files:    { type: "array",   required: true },
    },
  })
  .build();

The agent's OUTPUT step content is validated against this schema. If validation fails, the error is fed back and the model retries.

With Retry Count

.setOutputSchema(schema, 3) // retry up to 3 times

Field Types

type	JavaScript equivalent
"string"	string
"number"	number
"boolean"	boolean
"array"	Array<any>
"object"	object

Validation Errors

If all retries are exhausted, the run still completes — the last message in the history contains the model's best attempt. Check trace.errors to see validation failures.

Custom Validation

Use validateOutput directly for manual validation:

import { validateOutput } from "mitm-ai";

const result = validateOutput(someString, schema);
if (!result.valid) {
  console.log(result.errors);
} else {
  console.log(result.data); // typed Record<string, unknown>
}