tereno-mcp

🛡️ Check before you act — an MCP server for Base, over x402

Ask what it costs before you pay for it. Free catalog, pricing and receipt tools work with no wallet and no signup; paid answers settle per call in USDC, and reusing an answer another agent already paid for costs less.

npx -y tereno-mcp

⚡ Why this exists

An agent that reads a contract, signs a transaction or scrapes a page is acting on information it cannot verify. Most tools answer what something is. None of them tell you how long that answer stays true.

tereno-mcp puts Tereno inside any MCP client. Every paid answer comes back with the evidence behind it, the limits of that evidence, and the block it stops being valid at.

• No API key, no signup. The agent's wallet is the identity.

• Price before payment. tereno_price tells you the cost and whether the answer already exists, without a wallet and without committing to anything.

• Cheaper when shared. Deterministic answers are reused across agents: the first caller pays to compute, everyone after pays the reuse price.

Related MCP server: anchor-x402-mcp

🚀 Install

Add it to any MCP client — Claude Desktop, Claude Code, Cursor, Cline, Windsurf:

{
  "mcpServers": {
    "tereno": {
      "command": "npx",
      "args": ["-y", "tereno-mcp"]
    }
  }
}

Restart the client. Nothing else to configure — the free tools work immediately.

🆓 Free, no wallet needed

tereno_price is the one worth knowing about. It names the reuse tier out loud:

hit      another agent already paid to compute this and it is still fresh
partial  the durable half survived; only the expired part is recomputed
miss     nothing to reuse — this call computes it, and the next asker pays less

💳 Paid per call

Calling a paid tool returns a 402 carrying the payment challenge in error.data.paymentRequired. Sign it and retry with a PAYMENT-SIGNATURE header. If your agent already has an x402 wallet, that retry is the normal flow and this package never touches a private key.

🔒 transaction_intent_guard is never cached, shared or resold. An unsigned transaction is intent, and it stays with the wallet that paid for it.

⚙️ Configuration

🔐 What this package does and does not do

It is a stdio transport in front of the hosted endpoint at /api/mcp. Messages are forwarded verbatim, so the tool list, the prices and the payment challenge all come from the same place an HTTP agent sees — and this package needs no release when a capability changes.

The one thing it translates is payment: over HTTP the challenge arrives in a response header, and stdio has no headers, so it is folded into the JSON-RPC error payload where a client can still reach it.

No private key is ever read, stored or transmitted. There are no dependencies, and the whole thing is one readable file — read it before you let it run on your machine.

If your client supports remote MCP servers, skip this package and point it straight at https://www.tereno.xyz/api/mcp.

🌱 How it stays cheap — the cooperative layer

Tereno is a shared-cache coordination layer, not just an API. The first agent to pay for a given piece of verified work seeds it for the whole network; every later agent that reuses that answer pays less, and the seeder earns a small, non-transferable credit that discounts its own future calls.

Safety is a public good with a private cost. By making the first computation earn from every reuse, the network turns "I paid to check this contract" into "I lowered the price of checking it for everyone, and my own checks got cheaper."

The honest fine print: rewards are non-transferable credits, capped per artifact. They fund your agent's budget, they are not yield.

Discovery, scoring, reputation, pricing and the global cache live in the closed Tereno backend. This server and its SDK (tereno-client) are the public, open interface to it.

🤝 Support & community

• 💬 Questions / setup → Tereno Discord

• 🐛 Bugs → issues · ⚠️ never paste private keys or .env

• 🔒 Vulnerabilities → report privately

🔗 Links

Live catalog · OpenAPI · MCP registry entry · plugin-tereno for ElizaOS · tereno-client SDK

tereno.xyz · Verdicts before signatures, for agents on Base.