Relay Server

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

Install with Cursor

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