⚡ 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.
🚀 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
| Tool | The question it answers |
|---|
📖 tereno_catalog | What can Tereno answer, what does it cost, how long does each answer stay valid? |
🏷️ tereno_price | What would this exact call cost right now — and does the answer already exist? |
🧾 tereno_receipt | What did a settled call actually charge: tier, list price, credit applied, price paid? |
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
| Tool | Price | The question it answers |
|---|
🚦 transaction_intent_guard | $0.005 | Is this safe to sign? Simulation, gas, balance and allowance deltas, unlimited-approval flags |
🛡️ contract_guard | $0.001–3 | Is this contract safe to interact with? (code, proxy, pause) |
🕵️ contract_change | $0.001–2 | Did it change since last look? (rug-pull-after-audit detector) |
🪙 token_metadata | $0.001–3 | What token is this, really? (name, symbol, decimals, supply) |
🧬 contract_interface | $0.001–2 | ERC-20? NFT? Proxy? One bounded probe |
⛽ chain_snapshot | $0.001–2 | Latest Base block, base fee and suggested gas, zero parameters |
📄 web_compile | $0.001–5 | Public URL → bounded Markdown with resolved links, citations and a reusable artifact |
🔎 evidence_artifact | $0.001–3 | Can this public artifact be reused? Provenance, field validity, recomputation input |
🤝 demand_pledge | free | Name a capability you would pay for. Credit only after the same wallet pays for it later |
Calling a paid tool returns a 402 carrying the payment challenge in
error.data.paymentRequired, the payable resource URL in error.data.resource,
and the terms (network, asset, amount, payTo) in error.data.offer.
Over stdio you cannot pay by retrying the tool call. stdio has no headers in
either direction, so there is nowhere for a PAYMENT-SIGNATURE to travel back
through. Two ways to settle, both of which leave this package never touching a
private key:
- Pay the resource over HTTP. Sign
error.data.paymentRequired with your
x402 client and send the signed request to error.data.resource. It returns
the same payload the tool would have, receipt included, billed once.
- Use the remote server instead of this package. If your client supports
remote MCP, point it at
https://www.tereno.xyz/api/mcp. That transport does
have headers, so signing the challenge and retrying the same tool call is the
normal flow and everything stays inside MCP.
🔒 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
| Env | Default | Purpose |
|---|
TERENO_WALLET | — | Base address announced before payment, so a challenge can be bound to the wallet that will settle it. Optional. |
TERENO_BASE_URL | https://www.tereno.xyz | Point at another Tereno deployment. |
TERENO_TIMEOUT_MS | 45000 | Upstream request timeout. |
TERENO_EVIDENCE_INSTALLATION_ID | — | Optional stable random id for this MCP installation. It is hashed only when resolving evidence received from another agent; never use a wallet or secret. |
🔐 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, and the translation is lossy in one
direction. Over HTTP the challenge arrives in a response header and the caller
retries with a PAYMENT-SIGNATURE header. stdio has neither, so the challenge is
folded into the JSON-RPC error payload where a client can still reach it, while
the signature has no way back in. That is why a paid call is settled against the
resource URL rather than by retrying the tool, and why a client that speaks
remote MCP should prefer the hosted endpoint.
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.
🔗 Links
Live catalog ·
OpenAPI ·
MCP registry entry ·
plugin-tereno for ElizaOS ·
tereno-client SDK
tereno.xyz · Verdicts before signatures, for agents on Base.
