One tool. No account.

satledger's MCP server exposes a single tool, timestamp_receipt. Send a SHA-256 digest, receive a Time-Stamp Authority's signed RFC 3161 token over it — evidence that the data you hashed existed at that time, verifiable without trusting or contacting us.

$ npx add-mcp 'https://api.satledger.org/mcp'

Installs into Claude Code, Codex, Cursor and anything else that speaks MCP.

TOOLS: 1 AUTH: none PRICE: 0.05 USDC per call TRANSPORT: streamable http

What it does

You hash your data yourself. Only the digest is sent — the data never leaves your side — and nothing about the request is kept here afterwards. The token that comes back is the whole deliverable.

What you pay, and when

initialize and tools/list are free, so any agent can discover the tool and read its schema without paying. Only tools/call costs anything: 0.05 USDC, over x402, carried in _meta["x402/payment"]. There is no account to create, no API key to hold, and no balance to top up.

Calling it directly

The endpoint is ordinary JSON-RPC over HTTP, so nothing about MCP is required to use it:

$ curl -s https://api.satledger.org/mcp \ -H 'Content-Type: application/json' \ -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' {"result":{"tools":[{"name":"timestamp_receipt", ...}]}}

An unpaid tools/call answers with an x402 PaymentRequired challenge naming what it will accept, in both structuredContent and content[0].text.

Verifying what you get back

Check the token against the Time-Stamp Authority, not against us:

$ openssl ts -reply -in token.tsr -text

We cannot backdate one. Issuing a token for a time in the past would need the authority's private key, which we do not have.

What it proves, and what it does not

It proves the data you hashed existed by that time. It says nothing about what was hashed — a digest is not the document. And it bounds the time from above only: anyone can stamp an old file today, so a token is evidence of existence by a moment, never of creation at it.

Several digests at once

Send up to ten in a single call and a single payment, at the same price each. They are bound to one timestamp by a Merkle root, and every receipt still verifies on its own.

The rest of satledger is not on MCP

satledger's other product — signed usage ledgers for AI agents, with exports your customers verify offline — is an HTTP API at api.satledger.org, and it needs an account and a key. None of it is exposed over this MCP server, which has one tool and nothing else. If ledgers are what you came for, start at satledger.org instead; this page will not help you.