Mcp Agent Validator

[](https://github.com/agentprobe/mcp-agent-validator/actions)

AgentProbe (MCP Agent Validator)

Web-based multi-protocol validator for AI agent endpoints. Enter a URL and get instant assessment across eight protocol layers — HTTP, MCP, A2A/AP2, x402, OAuth, MCP Apps, HTML, and ERC-8004.

Live demo: https://agentprobe.xyz Video: https://www.youtube.com/watch?v=gnmsCEly3fA DoraHacks: https://dorahacks.io/buidl/39293

TL;DR

• Problem: Agent endpoints are hard to validate across multiple evolving protocols.
• Solution: One URL → unified assessment across HTTP, MCP, A2A/AP2, x402, OAuth, MCP Apps, HTML, and ERC-8004.
• Benefit: Faster debugging, safer integrations, and clearer compliance signals.

Demo Video

[](https://www.youtube.com/watch?v=gnmsCEly3fA)

Quickstart

git clone https://github.com/agentprobe/mcp-agent-validator.git
cd mcp-agent-validator
npm install
npm run start:dev

Open http://localhost:4000 in your browser and enter an endpoint URL to validate.

How It Works

• Input: A single agent endpoint URL.
• Assessment: Server runs the mcp-agent-assessment pipeline with protocol-specific validators.
• Output: Unified verdicts per protocol layer plus raw assessment output.

Features

• HTTP — Connectivity, HTTPS, SSL validation, CORS, HTTP/2 detection
• MCP — Server discovery, tool/resource/prompt listing, capability detection
• A2A / AP2 — Agent card validation, AP2 version and role detection via capabilities.extensions and X-A2A-Extensions header
• x402 — Payment-required endpoint detection with scheme, network, and token analysis
• OAuth — Authorization server metadata discovery
• MCP Apps — UI resource detection for MCP applications
• HTML — Website detection, Content-Type, SSL status, HTTP/2
• ERC-8004 — On-chain agent registry lookup with OASF classification, reputation, and metadata extraction

Architecture

flowchart LR
    A[URL Input] --> B[Server]
    B --> C[mcp-agent-assessment]
    C --> HTTP[HTTP]
    C --> MCP[MCP]
    C --> A2A[A2A/AP2]
    C --> X402[x402]
    C --> OA[OAuth]
    C --> APPS[MCP Apps]
    C --> HTML[HTML]
    C --> E8[ERC-8004]
    HTTP --> I[Results]
    MCP --> I
    A2A --> I
    X402 --> I
    OA --> I
    APPS --> I
    HTML --> I
    E8 --> I

API

POST /api/validate

Returns a structured validation result with separate sections for each protocol.

curl -X POST http://localhost:4000/api/validate \
  -H 'Content-Type: application/json' \
  -d '{"url": "https://your-endpoint.example.com"}'

Response contains mcp, a2a, ui (MCP Apps), and oauth objects with status, categories, summary, and messages. A2A results include AP2 version, roles, and extension URIs when detected.

POST /api/assess

Returns the raw assessment result from mcp-agent-assessment with full layer details.

curl -X POST http://localhost:4000/api/assess \
  -H 'Content-Type: application/json' \
  -d '{"url": "https://your-endpoint.example.com"}'

Optional parameters: timeout (number, ms), erc8004 (object with rpcNodes).

POST /api/lookup

Query the ERC-8004 on-chain registry for agent registration data, endpoints, OASF classification, and reputation.

curl -X POST http://localhost:4000/api/lookup \
  -H 'Content-Type: application/json' \
  -d '{"agentId": 2340, "chainId": 8453}'

| Key | Type | Description | Required | |-----|------|-------------|----------| | agentId | number | Agent token ID in the ERC-8004 registry | Yes | | chainId | number or string | Chain ID (e.g. 8453 for Base) or CAIP-2 (e.g. eip155:8453) | Yes | | rpcNodes | object | Custom RPC nodes per chain alias | No |

Authentication

Authentication is optional. When API_TOKEN is not set, the API is open (dev mode).

When API_TOKEN is set, two authentication methods are supported:

| Method | How it works | |--------|-------------| | Session Cookie | Browser visits GET / and receives a session cookie automatically. All subsequent API calls from the browser include the cookie. | | Bearer Token | External scripts send Authorization: Bearer header. |

# With Bearer token
curl -X POST http://localhost:4000/api/validate \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer your-token-here' \
  -d '{"url": "https://your-endpoint.example.com"}'

Environment Variables

| Variable | Required | Default | Description | |----------|----------|---------|-------------| | PORT | No | 4000 | Server port | | API_TOKEN | No | - | When set, enables authentication for API endpoints |

Project Structure

src/
├── server/
│   ├── Server.mjs          # HTTP server, routing, auth, API handlers
│   └── StaticFiles.mjs     # Static file serving for docs/
├── mcp/
│   └── McpServer.mjs       # Built-in MCP server (validate, lookup, client introspection)
├── prober/
│   ├── AssessmentProbe.mjs  # Maps assessment results to UI-friendly format
│   └── AgentLookup.mjs     # Direct ERC-8004 on-chain registry queries
docs/
├── index.html              # Single-page frontend
└── style.css               # Styles
tests/
└── unit/
    ├── server.test.mjs     # Server route, auth, and API tests
    ├── static-files.test.mjs
    └── assessment-probe.test.mjs

Dependencies

• mcp-agent-assessment — Unified assessment pipeline (MCP, A2A/AP2, x402, OAuth, MCP Apps)
• a2a-agent-validator — A2A agent card and AP2 extension detection
• x402-mcp-validator — x402 payment protocol validation
• mcp-apps-validator — MCP Apps UI resource detection
• erc8004-registry-parser — ERC-8004 on-chain registry parsing

Built by

a6b8

License

MIT

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: AgentProbe
• Source: AgentProbe/mcp-agent-validator
• License: MIT
• Homepage: https://agentprobe.xyz

Install and usage instructions live in the source repository linked above.