Add richer validation to your fields You use the fluent builder for limits, nested objects, arrays, optional fields, and richer descriptions. Validation becomes part of the program instead of cleanup after it. typescript academy academy/topics/fluent-fields-validation website/content-src/academy/course.mjs academy Add richer validation to your fields
ax
TypeScript @ax-llm/ax
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Unit 2 · Make AI outputs predictable

Add richer validation to your fields

You use the fluent builder for limits, nested objects, arrays, optional fields, and richer descriptions. Validation becomes part of the program instead of cleanup after it.

f()8 focused minutesNot started
Worked example

See the idea in context

const signature = f().input('text', f.string().min(1)).output('score', f.number().min(0).max(1)).build();
  1. Reject empty input

    min(1) makes the text requirement executable.

  2. Bound the score

    The output must stay between zero and one.

  3. Build one signature

    build() finishes the reusable input and output contract.

Run itIn your own project
npm install @ax-llm/ax

import { ai, ax } from '@ax-llm/ax';

const llm = ai({ name: 'openai', apiKey: process.env.OPENAI_APIKEY! });
const classify = ax('review:string -> sentiment:class "positive, negative, neutral"');

const result = await classify.forward(llm, {
  review: 'Useful and boring in the best way.',
});

Set OPENAI_APIKEY in your environment before running provider-backed code.

In the ax repo

From a clone of the ax repo:

npm run example -- typescript src/examples/typescript/generation/structured.ts
Active practice

Show that you can use it

Answer 2 in a row to learn this · attempt 1
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Source-backed follow-up