Relay MCP Server

Relay MCP Server

A Model Context Protocol server for Relay Protocol — cross-chain bridge and swap tools for AI agents.


Tools (16)

Quoting & Routing

| Tool | Description | |------|-------------| | get_bridge_quote | Quote for bridging same token across chains | | get_swap_quote | Quote for swapping between different tokens (same-chain or cross-chain) | | estimate_fees | Fee breakdown for a bridge or swap route |

Token & Chain Discovery

| Tool | Description | |------|-------------| | get_supported_chains | List supported blockchain networks (slim response) | | get_supported_tokens | Search for tokens across chains | | get_trending_tokens | Currently trending tokens across Relay-supported chains | | get_token_price | Current USD price of a token | | get_token_details | Full token fundamentals: price, market cap, volume, liquidity, optional price chart | | get_swap_sources | List DEX aggregators and AMMs that Relay routes through |

Chain Health

| Tool | Description | |------|-------------| | check_chain_status | Chain health, solver liquidity, and route configuration (3 API calls in 1 tool) |

Transaction Tracking

| Tool | Description | |------|-------------| | get_transaction_status | Check status by request ID or on-chain tx hash | | get_transaction_history | Past transactions for a wallet | | index_transaction | Tell Relay to index a transaction it may have missed |

Integrator Tools

| Tool | Description | |------|-------------| | get_app_fees | Claimable app fee balances and claim history (2 API calls in 1 tool) | | get_relay_app_url | Deep link to the Relay web app with pre-filled parameters | | get_api_schema | Discover Relay API endpoints and inspect their schemas |

Usage

Claude Desktop / Claude Code

Add to your claude_desktop_config.json or .claude.json:

{
  "mcpServers": {
    "relay": {
      "command": "npx",
      "args": ["-y", "@relayprotocol/relay-mcp"]
    }
  }
}

Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "relay": {
      "command": "npx",
      "args": ["-y", "@relayprotocol/relay-mcp"]
    }
  }
}

Run from source

npm install
npm run build
npm start

Environment variables

| Variable | Default | Description | |----------|---------|-------------| | RELAY_API_URL | https://api.relay.link | Relay API base URL | | RELAY_API_KEY | — | Optional API key for higher rate limits |

Features

• Chain name resolution — Pass "base", "ethereum", "arb" instead of numeric chain IDs. Supports aliases and fuzzy matching.
• Input validation — Addresses, amounts, and chain IDs are validated before hitting the API, with clear error messages.
• Bundled tools — check_chain_status and get_app_fees combine multiple API calls into single tools with parallel fetching.
• Decision-tree descriptions — Tool descriptions guide agents to pick the right tool ("For just the price, use get_token_price. For full fundamentals, use get_token_details.").
• Slim responses — Responses are trimmed to essential fields. Chart data is downsampled from ~21KB to ~3KB.
• API schema discovery — get_api_schema lets agents explore available endpoints on demand (progressive disclosure pattern).
• Tx hash lookup — get_transaction_status accepts either a request ID or an on-chain transaction hash.
• Structured errors — Errors are categorized (validation, api, network, rate_limit, server, auth) with retryability hints.

Architecture

• Transport: Stdio (MCP spec)
• Runtime: Node.js >=20
• API: Direct HTTP calls to api.relay.link (no SDK dependency)
• Read-only: Returns quotes, fees, and status. Does not sign or broadcast transactions.

Agent flow examples

User: "Bridge 0.1 ETH from Ethereum to Base"

1. Agent calls get_bridge_quote(originChainId="ethereum", destinationChainId="base", ...)
   → chain names resolved automatically, quote returned with fees and ETA
2. Agent shows user the quote and a link to execute on relay.link

User: "What tokens are trending on Base?"

1. Agent calls get_trending_tokens(chainId="base")
   → returns token identities (no prices)
2. Agent calls get_token_price for each interesting token
   → returns current USD prices

License

MIT