x402 Service Discovery MCP Server

The community-built Bazaar for the x402 agentic economy — 251+ live services, real-time quality signals, facilitator-compatibility checks, and ERC-8004 trust scoring. The discovery layer that Coinbase's own PROJECT-IDEAS.md asked the community to build.

What This Is (30 seconds)

x402 is Coinbase's HTTP-native micropayment standard for the agentic web. An AI agent hits an endpoint, gets an HTTP 402 challenge, pays with USDC on Base, and receives data — no API keys, no subscriptions, pure machine-to-machine.

The problem: 251+ x402-payable services exist across the ecosystem. The official x402.org catalog lists names. That's it. No uptime data. No latency scores. No facilitator-compatibility flags. No trust signals. An agent has no way to know which services are actually live, trustworthy, or compatible with its payment flow.

This MCP server solves it. Connect any Claude, Cursor, or Windsurf agent directly to the x402 Service Discovery API — a continuously-updated catalog with real quality signals on every entry. Find services, check health, verify facilitator compatibility, and register new endpoints — all from inside your AI workflow.

MCP Tools (5 tools)

Quickstart — 30 Seconds to Discovery

Option A: Docker (recommended)

Add to your claude_desktop_config.json, Cursor MCP settings, or Windsurf config:

{
  "mcpServers": {
    "x402-discovery": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "ghcr.io/rplryan/x402-discovery-mcp:latest"]
    }
  }
}

Option B: npx (no Docker required)

{
  "mcpServers": {
    "x402-discovery": {
      "command": "npx",
      "args": ["-y", "@rplryan/x402-discovery-mcp"]
    }
  }
}

Option C: Direct API

The Discovery API is publicly accessible — no authentication required:

# Search for services
curl "https://x402-discovery-api.onrender.com/discover?query=blockchain+analytics&max_price_usd=0.01"

# Full catalog
curl "https://x402-discovery-api.onrender.com/.well-known/x402-discovery"

Why This Matters

The Discovery Gap in x402

The x402 protocol solves payment. It does not solve discovery. When 251+ services exist but agents can't find, evaluate, or route to them intelligently, the protocol's full value is unrealized.

This project fills that gap with three layers:

1. Discovery — Find x402 services by capability, category, price ceiling
2. Quality signals — Uptime %, latency (ms), facilitator compatibility, ERC-8004 trust score
3. Routing intelligence — Companion x402 RouteNet selects the optimal service from discovery results

What Makes This Different from x402.org/ecosystem

Live Catalog Stats

Total Services:      251+
Auto-scan interval:  6 hours
Scan sources:        x402.org/ecosystem, awesome-x402, x402scan.com
Categories:          data, compute, agent, utility
Facilitator-compat:  Flagged per service
Trust signals:       ERC-8004 per service
API uptime:          Live at https://x402-discovery-api.onrender.com

Catalog Sample

Example: Agent Workflow

# 1. Agent needs blockchain analytics under $0.01
result = x402_discover(
    query="blockchain analytics whale tracking",
    max_price_usd=0.01,
    category="data"
)
# Returns: ranked list with price, uptime %, latency, llm_usage_prompt

# 2. Verify the top result is facilitator-compatible before paying
compat = x402_facilitator_check(url=result[0]["url"])
# Returns: {facilitator_compatible: true, payment_details: {...}}

# 3. Check live health before committing
health = x402_health_check(url=result[0]["url"])
# Returns: {status: "healthy", latency_ms: 142, uptime_pct: 99.1}

# 4. Now pay via x402 — agent proceeds with confidence

This is EIP-712 signed TransferWithAuthorization via the x402 HTTP protocol — not direct ERC-20 transfer. The signature is verified server-side; on-chain settlement via receiveWithAuthorization is the next tier.

CDP Builder Grant Context

This project is a direct implementation of two items from Coinbase's own public roadmap:

From PROJECT-IDEAS.md in coinbase/x402:

"Dynamic Endpoint Shopper — An agent that discovers an MCP registry, pays for access, chains results from multiple services"

From the CDP x402 facilitator roadmap:

"A discovery layer for buyers (human and agents) to find available services (Bazaar)"

We built the community Bazaar. It's live. It has 251+ services. It has quality signals the official page doesn't. And it uses x402 payments itself — x402_discover costs $0.005 USDC, paid via the protocol it serves.

What We've Shipped (11 days)

Related Projects

Register Your Service

If you're building an x402-enabled service, add it to the catalog:

curl -X POST https://x402-discovery-api.onrender.com/register \
  -H "Content-Type: application/json" \
  -d '{
    "name": "My Service",
    "url": "https://myservice.example.com/api",
    "price_usd": 0.005,
    "category": "data",
    "description": "What your service does",
    "network": "base-mainnet"
  }'

Or use the x402_register MCP tool from inside Claude/Cursor/Windsurf.

Architecture

┌─────────────────────────────────────────────────────┐
│              AI Agent (Claude / Cursor / Windsurf)  │
│                                                     │
│  x402_discover → x402_health_check → x402_trust     │
│  x402_facilitator_check → x402_register             │
└───────────────────┬─────────────────────────────────┘
                    │ MCP (stdio/Docker)
┌───────────────────▼─────────────────────────────────┐
│          x402 Discovery MCP Server                  │
│          ghcr.io/rplryan/x402-discovery-mcp         │
└───────────────────┬─────────────────────────────────┘
                    │ HTTPS
┌───────────────────▼─────────────────────────────────┐
│     x402 Discovery API (Render, v3.3.0)             │
│     https://x402-discovery-api.onrender.com         │
│                                                     │
│  • 251+ services  • Auto-scan every 6h              │
│  • Health checks  • Facilitator compat flags        │
│  • ERC-8004 trust • llm_usage_prompt per service    │
└─────────────────────────────────────────────────────┘

💬 Community

Built something with x402 Service Discovery? Found a service that should be in the catalog? Share it in our Show and Tell discussion thread.

License

MIT

Built on Coinbase x402 protocol | Base Network | ERC-8004 | Model Context Protocol