# Autoblocks × Val Town

##### Build custom AI evals in minutes

[Fork the sample Val](https://www.val.town/x/autoblocks/Autoblocks_Webhook_Evaluator)

Every AI team eventually hits the same wall: the built‑in “accuracy” or “helpfulness” metrics just don’t cut it once real users—and real edge‑cases—show up. You need evaluations that understand your domain, your data, your definition of _done_.

Today we’re making that dead simple. 🪄

Autoblocks now pairs seamlessly with [**Val Town**](https://www.val.town/)—the delightfully lightweight serverless playground—to let you spin up custom evaluators with nothing more than a URL and a few lines of JavaScript.

### **Why we built this**

1. **Your rules, your way** - Regulated industries (hi, healthcare friends 👋) can’t rely on fuzzy generic scores. You need hard “pass/fail” logic and auditable reasoning.

2. **No infra tax** - Standing up a microservice just to grade a prompt feels… overkill. Val Town gives you an always‑on endpoint without touching Kubernetes.

3. **Instant feedback loop** - Kick off a simulation in Autoblocks, watch Val Town log the payload, return a score, and see the result light up in the UI—all in one coffee’s time.

### **How it works**

1. **Create a Val** - Drop the code below into a new Val. (Yes, that’s the whole thing.)

```javascript
// https://www.val.town/v/yourname/autoblocksWebhook

import type { Evaluation } from "@autoblocks/client/testing";

export default async function httpHandler(req: Request): Promise<Response> {
    if (req.method !== "POST") return Response.json({ error: "Use POST" }, { status: 405 });

const { input, output } = await req.json();

// TODO: your logic here — LLM-as-judge, regex checks, whatever

const score = 0.9;

const evalObj: Evaluation = {
        score,
        threshold: { gte: 0.8 },
        metadata: { notes: "Passed identity‑check flow" },
    };

return Response.json(evalObj);
}
```

2. **Paste the URL into Autoblocks** - Head to **Evaluators → Webhook → Settings**, drop in your Val URL, add an auth header, hit _Save_.

3. **Simulate away** - Run an Agent Simulation. Autoblocks ships the full scenario + transcript to your Val; Val Town runs your code and hands back the verdict in milliseconds. The score, threshold, and metadata pop straight into the Evaluations tab.

That’s it—custom grading logic without spinning up a single server.

### **What you can build**

- **HIPAA‑grade phone‑call checks** (Did the agent verify DOB before sharing PHI?)
- **Multi‑turn tone audits** (Flag any response with CAPS LOCK RAGE)
- **Security red‑teamers** (Catch prompt‑injections before they hit prod)
- **Fun stuff** (Give bonus points for using _y’all_ in a reply—why not?)

If you can express it in code, you can evaluate it.

### **Get started**

- **Read the docs:** [Webhook Evaluators →](https://docs.autoblocks.ai/v2/agent-simulate/evaluators#webhook-evaluators)
- **Fork the sample Val:** [autoblocks/Autoblocks_Webhook_Evaluator](https://www.val.town/x/autoblocks/Autoblocks_Webhook_Evaluator)
- **Show us what you build:** Tag [@AutoblocksAI](https://x.com/autoblocksai) and [@ValDotTown](https://x.com/ValDotTown) on X / LinkedIn—we love a good demo thread.

This integration turns Autoblocks into a _choose‑your‑own‑rubric_ adventure. No waiting on us to ship the “perfect” metric. You’ve already got the perfect metric in your head; now you can encode it in a Val and see it live in Autoblocks in under five minutes.

Happy grading. 🚀