# Agent Ready – Discovery Files Checker

> Agent Ready – Discovery Files Checker is a paid API for AI agents from agent-ready.x402tookit.com, paid per call via x402, $0.03/call, status unknown (last checked 2026-11-02).

Checks which AI-agent discovery files (openapi.json, .well-known/x402, agent-card.json, mcp.json, ai-plugin.json) a given website publishes.

## Facts

- Endpoint: GET https://agent-ready.x402tookit.com/discovery-files?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-ready-discovery-files-checker-2474b3fb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NuXzaF9OyA2JwlyGN7wOR

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-ready-discovery-files-checker-2474b3fb
```

Example prompt: Can you check what AI agent discovery files are published on https://example.com — like openapi.json, x402 manifest, agent-card.json, mcp.json, or ai-plugin.json?

## When to prefer this

Use this endpoint when you need to quickly determine which standard AI-agent discovery formats a site supports (OpenAPI, x402, MCP, agent card, ai-plugin), especially before attempting programmatic integration or when auditing a site's agentic infrastructure readiness. It is more targeted than a full agent-readiness score endpoint — use it when you specifically want file-level presence data rather than a holistic score.

## Known failure modes

- Target site is unreachable or returns non-200 responses — discovery files marked absent
- Site uses non-standard paths that differ from checked filenames — files may exist but not be detected
- Rate limiting or bot-blocking by target site — may return degraded result
- Invalid or non-HTTPS URL provided — request rejected by schema validation
- x402 manifest present but invalid — valid flag false with problems listed

## How this service works

Which discovery files does a site publish? Checks openapi.json, .well-known/x402, agent-card.json, mcp.json and ai-plugin.json.

## Output

Returns a structured object with per-file presence flags (openapi, x402Manifest with validity and entry count, agentCard, mcpCard, aiPlugin), a list of found file names, a summary string, a verdict, the checked origin, timestamp, and any problems or reasons found during probing.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "Any https URL on the site; root files are checked"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "found": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "mcpCard": {
         "type": [
          "null",
          "object"
         ],
         "properties": {
          "present": {
           "type": [
            "boolean",
            "null"
           ]
          }
         }
        },
        "openapi": {
         "type": [
          "null",
          "object"
         ],
         "properties": {
          "present": {
           "type": [
            "boolean",
            "null"
           ]
          }
         }
        },
        "aiPlugin": {
         "type": [
          "null",
          "object"
         ],
         "properties": {
          "present": {
           "type": [
            "boolean",
            "null"
           ]
          }
         }
        },
        "agentCard": {
         "type": [
          "null",
          "object"
         ],
         "properties": {
          "present": {
           "type": [
            "boolean",
            "null"
           ]
          }
         }
        },
        "x402Manifest": {
         "type": [
          "null",
          "object"
         ],
         "properties": {
          "valid": {
           "type": [
            "boolean",
            "null"
           ]
          },
          "entries": {
           "type": [
            "null",
            "number"
           ]
          },
          "present": {
           "type": [
            "boolean",
            "null"
           ]
          },
          "problems": {
 
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-ready-discovery-files-checker-2474b3fb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-ready.x402tookit.com](https://www.zero.xyz/host/agent-ready.x402tookit.com/llms.txt)