# Agent Card & Well-Known Validator

> Agent Card & Well-Known Validator is a paid API for AI agents from agent-card-validator-mcp.mtree.workers.dev, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Validates agent cards and .well-known routes for autonomous agents, returning provenance, route-specific evidence, and machine-readable compliance fields

## Facts

- Endpoint: POST https://agent-card-validator-mcp.mtree.workers.dev/v1/wellknowns/audit
- 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/agent-card-well-known-validator-38b64fd6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vD-ji0p0NghyUo-bhNNZM

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 agent-card-well-known-validator-38b64fd6 -d '<json body>'
```

Example prompt: Can you audit the agent card and well-known routes for https://myagent.example.com and tell me if the provenance and machine-readable fields check out?

## When to prefer this

Use this endpoint when you need to programmatically verify that an autonomous agent's card and .well-known discovery routes are correctly configured, accessible, and contain valid machine-readable fields. Prefer this over manual inspection when building agent registries, marketplaces, or orchestration systems that need to trust agent identity metadata. Especially useful for agentic pipelines that must confirm compliance before routing tasks to a discovered agent.

## Known failure modes

- Target URL is unreachable or returns non-200 response — validation fails with connectivity error
- Agent card URL malformed or missing — returns error indicating invalid input
- Payment not provided or insufficient USDC via x402 — returns 402 Payment Required
- Well-known route returns unexpected content type or structure — partial validation with evidence of failure
- Rate limiting or Cloudflare Worker timeout on slow target domains

## How this service works

Paid agent card and well-known validator route for autonomous agents. Returns JSON with provenance, route-specific evidence, and machine-readable fields. Price 0.05 USDC on Base via x402. Demo/preview: https://agent-card-validator-mcp.mtree.workers.dev/demo/audit. Contact: https://agent-card-validator-mcp.mtree.workers.dev/contact.

## Output

A JSON object containing validation results with provenance information, route-specific evidence for each well-known endpoint audited, and machine-readable compliance fields indicating whether the agent card and associated routes meet expected standards.

## Example request

```json
{
 "input": {
  "body": {
   "base_url": "https://example-agent.com"
  },
  "type": "http",
  "method": "POST",
  "bodyType": "json"
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "url": {
       "type": "string"
      }
     },
     "additionalProperties": true
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-card-well-known-validator-38b64fd6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-card-validator-mcp.mtree.workers.dev](https://www.zero.xyz/host/agent-card-validator-mcp.mtree.workers.dev/llms.txt)