---
name: verifier-builder
description: Two-agent observer pattern. Builder writes code. Verifier re-checks every claim with read-only tools. Catches mistakes before production.
user-invocable: true
---

# Verifier-Builder Pattern

Set up a two-agent observer system where a read-only verifier checks every claim the builder makes.

## Architecture

```
Builder (your terminal) ---unix socket---> Verifier (new window, input LOCKED)
  |                                          |
  v writes:                                  v reads (read-only):
  session.jsonl                              session.jsonl
  |                                          |
  <--- verifier_prompt (corrective feedback) ---'
```

## Key Properties

- Builder DOES NOT KNOW verifier exists (pure observer)
- Verifier input is LOCKED (structurally un-promptable)
- Verifier has NO write tools
- Max 3 correction loops, then escalate to human

## Protocol

```typescript
Verifier -> Builder: hello, prompt(correction), report(status), ping, bye
Builder -> Verifier: hello_ack, prompt_ack, event(start/stop/error), pong
```

## Verifier Persona

```yaml
name: Verifier
tools: [Read, Grep, Glob, LS, Find, VerifierPrompt]
input_locked: true
max_loops: 3
```

## Usage

```bash
just verifier
```

$ARGUMENTS