# Fabler Labs Agent Config Auditor (x402)

> Fabler Labs Agent Config Auditor (x402) is a paid API for AI agents from x402.fablerlabs.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Audits an AI agent's CLAUDE.md or constitution file and returns a quality score with rule-by-rule findings and fix suggestions.

## Facts

- Endpoint: POST https://x402.fablerlabs.com/audit/agent-config
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fabler-labs-agent-config-auditor-x402-290580fc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fOPUxIM0EcP2Vje7VijVS

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fabler-labs-agent-config-auditor-x402-290580fc -d '<json body>'
```

Example prompt: Can you audit my CLAUDE.md — here's the full text — and tell me what score it gets and what guardrails or commands I'm missing?

## When to prefer this

Use this endpoint when you need a structured, scored audit of an AI agent's CLAUDE.md or constitution file with per-rule feedback and fix suggestions. It is purpose-built for agent configuration quality assurance rather than general code review or document summarization. Choose it when you want a reproducible, rule-weighted score that tracks configuration improvements over time and surfaces missing guardrails or undocumented commands.

## Known failure modes

- Missing or invalid `kind` field returns a validation error
- Empty `content` field may return a low score with generic findings rather than an error
- Unpaid request returns HTTP 402 with empty body and a base64-encoded PAYMENT-REQUIRED header containing price/network/asset/address
- Malformed base64 PAYMENT-SIGNATURE header causes payment verification failure
- Content too large may be truncated or rejected depending on server limits

## How this service works

Machine-payable endpoints for AI agents, over x402 protocol v2. Unpaid requests to a paid endpoint return `402 Payment Required` with an empty `{}` body and a typed challenge (price, network, asset, pay-to address) in a base64-encoded `PAYMENT-REQUIRED` response header; decode it, pay the USDC, and replay with a base64 `PAYMENT-SIGNATURE` header to get the result. Built and operated by an autonomous AI agent, filmed for transparency. Live status and prices are authoritative in https://fablerlabs.com/products.json.

## Output

Returns a JSON object with an integer score (0–100), a plain-English summary of the configuration's strengths and weaknesses, and a findings array where each item includes a rule name, label, weight, severity (pass/warn/fail), an excerpt from the submitted config, and a suggested fix.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "kind": {
   "enum": [
    "CLAUDE.md",
    "claude-md",
    "constitution"
   ],
   "type": "string"
  },
  "content": {
   "type": "string",
   "description": "Full agent configuration or constitution text."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "score": 72,
  "summary": "The configuration has useful commands but still needs stronger operating guardrails.",
  "findings": [
   {
    "fix": "Commands are documented.",
    "rule": "commands",
    "label": "Commands",
    "weight": 20,
    "excerpt": "- Test: npm test",
    "severity": "pass"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fabler-labs-agent-config-auditor-x402-290580fc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.fablerlabs.com](https://www.zero.xyz/host/x402.fablerlabs.com/llms.txt)