Nostr Signer

Approve Nostr signatures with your own browser signer without exposing a private key.

CommunityOnlineNo sign-inGlobalFreeRead-only

What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Approve Nostr signatures with your own browser signer without exposing a private key.

    How to connect

    How to connect Nostr Signer to Claude

    The server address to paste into Claude settings:

    https://signer.frontiercrown.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 Nostr Signer to ChatGPT

    The server address to paste into ChatGPT settings:

    https://signer.frontiercrown.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 Nostr Signer to Cursor

    The server address to paste into Cursor settings:

    https://signer.frontiercrown.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 (17)

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

    get_setup_urlReturn the loopback-only page used to connect a NIP-07 browser extension or an advanced NIP-46 signer.
    get_signer_statusCheck whether a user-controlled NIP-07 or NIP-46 signer is connected.
    begin_nostrconnect_pairingAdvanced fallback: create a nostrconnect:// URI for the user to scan or open in a remote signer. Never accepts an nsec.
    connect_bunkerConnect a bunker:// URI only when the user knowingly supplied it. Prefer the local setup page so connection secrets are not placed in chat. Never accepts an nsec.
    get_public_keyReturn the public key exposed by the currently paired signer.
    prepare_notePrepare and bind an exact unsigned kind:1 note for user review. This does not sign or publish.
    prepare_eventValidate and bind an exact unsigned Nostr event for user review. This does not sign or publish. Show the user every field before requesting a signature.
    sign_eventAsk the paired signer to approve and sign the exact event bound to a fresh intent. Requires explicit user intent and never publishes.
    publish_eventPublish a previously verified signed event to configured relays. Requires separate explicit user intent.
    query_eventsRead a bounded set of verified public profile or note events from selected relays.
    disconnect_signerForget the in-memory signer session and all prepared events.
    get_grynvault_account_dashboardRead the connected Nostr identity's Grynvault supporter, payment, and NIP-05 dashboard using a short-lived signed authorization. This does not create an invoice or change settlement.
    approve_grynvault_browser_handoffSign a short-lived, read-only Grynvault account handoff code so the browser tab that created it can receive its own dashboard. This does not create an invoice, publish a Nostr event, change settlement, or grant wallet custody.
    prepare_grynvault_supporter_invoicePrepare an exact, short-lived signed-authorization request for a one-time donation of 21 to 1,000,000 sats or the fixed 2,100-sat 30-day membership. Does not sign, create, pay, or settle an invoice.
    create_grynvault_supporter_invoiceAfter separate explicit user confirmation, sign the prepared authorization and create exactly one pending Grynvault supporter invoice. Does not pay it and never treats a redirect as settlement.
    prepare_grynvault_nip05_invoiceCheck and normalize a name@frontiercrown.com identifier, then prepare its exact 2,000-sat invoice authorization. Does not sign, reserve the name, create, pay, or settle an invoice.
    create_grynvault_nip05_invoiceAfter separate explicit user confirmation, sign the prepared authorization and create exactly one pending 2,000-sat name@frontiercrown.com invoice. Does not pay, settle, activate, or prove identity.