x402engine-mcp

curated MCP server for x402engine, built for agents that want to discover and call paid tools over HTTP 402.

the core story is simple: software pays software, per call, with stablecoins. no api keys. no accounts. no subscription setup in the request path.

why agents use this

• curated MCP surface over the live x402engine gateway
• machine readable discovery via discover_services
• payment rails on Base, MegaETH, and Solana
• useful for agents that want to buy compute, crypto data, wallet analytics, IPFS, and travel search only when needed

important scope note:

• the live gateway exposes a larger catalog than this MCP package
• this package is intentionally a curated subset
• for full gateway discovery, use discover_services or read https://x402-gateway-production.up.railway.app/.well-known/x402.json

quick start

claude desktop

{
  "mcpServers": {
    "x402engine": {
      "command": "npx",
      "args": ["-y", "x402engine-mcp"],
      "env": {
        "X402_DEV_BYPASS": "your-dev-bypass-secret"
      }
    }
  }
}

claude code

claude mcp add x402engine -- npx -y x402engine-mcp

machine readable discovery surfaces

• gateway discovery: https://x402-gateway-production.up.railway.app/.well-known/x402.json
• agent card: https://x402-gateway-production.up.railway.app/.well-known/agent.json
• endpoint manifest: https://x402-gateway-production.up.railway.app/.well-known/agent-manifest.v1.json
• manifest integrity: https://x402-gateway-production.up.railway.app/.well-known/agent-manifest-integrity.v1.json
• services api: https://x402-gateway-production.up.railway.app/api/services
• this package metadata: server.json

implemented MCP tools

discovery and health

| tool | price | description | |------|-------|-------------| | discover_services | free | fetch live x402 discovery metadata from /.well-known/x402.json | | service_health | free | fetch live per-service health metrics from /api/health/services |

image generation

| tool | price | description | |------|-------|-------------| | generate_image | $0.015 to $0.12 | image generation across fast, quality, and text tiers |

code execution

| tool | price | description | |------|-------|-------------| | execute_code | $0.005 | sandboxed code execution |

audio

| tool | price | description | |------|-------|-------------| | transcribe_audio | $0.10 | audio transcription via Deepgram |

crypto and market data

| tool | price | description | |------|-------|-------------| | get_crypto_price | $0.001 | current crypto prices | | get_crypto_markets | $0.002 | market rankings and market data | | get_crypto_history | $0.003 | historical price data | | get_trending_crypto | $0.001 | trending coins | | search_crypto | $0.001 | search by name or symbol | | get_crypto_categories | $0.001 | CoinGecko category ids for sector discovery |

wallet and token data

| tool | price | description | |------|-------|-------------| | get_wallet_balances | $0.005 | multichain wallet balances | | get_wallet_transactions | $0.005 | wallet transaction history | | get_wallet_pnl | $0.01 | wallet profit and loss analysis | | get_token_prices | $0.005 | dex derived token prices | | get_token_metadata | $0.002 | token metadata |

IPFS

| tool | price | description | |------|-------|-------------| | pin_to_ipfs | $0.01 | pin json to IPFS | | get_from_ipfs | $0.001 | retrieve content from IPFS by cid |

travel

| tool | price | description | |------|-------|-------------| | search_flights | $0.02 | flight search via /api/travel/flights | | search_locations | currently unavailable on the live gateway | MCP tool exists but targets /api/travel/locations, which is not in the current gateway routes | | search_hotels | $0.02 | hotel search via /api/travel/hotels | | search_cheapest_dates | currently unavailable on the live gateway | MCP tool exists but targets /api/travel/cheapest-dates, which is not in the current gateway routes |

what this package does not expose yet

notable live gateway capabilities that are outside this curated MCP surface:

• 38 LLM routes under /api/llm/*
• embeddings via /api/embeddings
• video generation via /api/video/*
• web routes via /api/web/*
• search routes via /api/search/*
• tts routes via /api/tts/*
• ens routes via /api/ens/*
• tx simulation via /api/tx/simulate

environment variables

| variable | required | description | |----------|----------|-------------| | X402_BASE_URL | no | gateway url. defaults to https://x402-gateway-production.up.railway.app | | X402_DEV_BYPASS | no | dev bypass secret for local testing | | X402_PAYMENT_HEADER | no | pre signed x402 payment header for automatic payment |

payment rails

• base: USDC, 6 decimals
• solana: USDC, 6 decimals
• megaeth: USDm, 18 decimals

request flow

1. the agent calls an MCP tool
2. this server makes the matching HTTP request to the gateway
3. if payment is required, the gateway returns 402 Payment Required plus payment metadata
4. the caller pays with an x402 compatible payment flow
5. the gateway verifies payment and returns the result

for automatic payment handling in custom agent code, use @x402/fetch.

trust and distribution links

• website: x402engine.app
• gateway base url: x402-gateway-production.up.railway.app
• npm: x402engine-mcp
• github: agentc22/x402engine-mcp
• protocol: x402.org