mcp

Issue signed receipts for AI agent actions; verify any receipt offline - free, no account.

CommunityOnlineAPI key requiredGlobalFreeRead-only

What it can do

    What data it sees

    Do you need an account

    An API key from the service settings is required

    Issue signed receipts for AI agent actions; verify any receipt offline - free, no account.

    How to connect

    How to connect mcp to Claude

    The server address to paste into Claude settings:

    https://mcp.pcrzero.com/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect mcp to ChatGPT

    The server address to paste into ChatGPT settings:

    https://mcp.pcrzero.com/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect mcp to Cursor

    The server address to paste into Cursor settings:

    https://mcp.pcrzero.com/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (3)

    Raw names from tools/list. Only developers need these.

    issue_receiptAdjudicates an attestation document against a policy and returns the verdict together with a signed receipt pair — the durable, independently checkable proof that this decision was made, by these keys, over this document. **Metered: every call bills one `receipt_verifications` unit against the API key configured for this server, and a `fail` verdict bills exactly like a `pass`. You are paying for the adjudication, not for the answer you wanted.** This is the only tool here that spends. If you already hold a receipt and want to know whether it is genuine, that is `verify_receipt`, which is free and needs no key.
    verify_receiptChecks a PCRZERO receipt pair against the signing keyset: whether the signature holds, and whether the receipt says what it appears to say. **Free, with no API key and no account, and it stays free.** Offline by default — supply `keyset` and this call touches the network not at all; omit it and the server fetches the public keyset from api.pcrzero.com once. The result field `keyset_source` tells you which of the two happened, every time. This tool issues nothing, bills nothing, and cannot spend. It is the half of PCRZERO you never pay for.
    get_keysetReturns the current PCRZERO signing keyset — key ids, public halves, and each key's status. Public and unauthenticated: no API key, no cost, no account. This is the same document an outside party fetches to check a PCRZERO receipt without trusting us, and fetching it is how you stop taking our word for anything.