# Nostr Signer (remote · signer.frontiercrown.com)

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

- Trust score: 69/100 (medium)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-28

## Components

- remote · `signer.frontiercrown.com`: 69/100 (this document), [markdown](https://verifymcp.io/servers/com-frontiercrown-signer-nostr-signer/signer.md), [page](https://verifymcp.io/servers/com-frontiercrown-signer-nostr-signer/signer)

## Channel facts

- Endpoint: `https://signer.frontiercrown.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.4.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-28.

- **Endpoint Security**: 57/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (publish_event).
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 75/100
  - AI-judged instruction clarity (good).
  - Tool/resource definitions use about 1156 tokens (~68/item across 17 items; 17 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 45/100
  - Stability check failed: schema churn in the 17 days we've observed: 2 tool removals, 0 breaking changes, 0 auth/transport breaks, 0 additions.
- **Tool Coverage**: 77/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 32% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - All 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
  - An AI judge read all 18 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the Nostr Signer MCP server?

Nostr Signer is a hosted endpoint at https://signer.frontiercrown.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http com-frontiercrown-signer-nostr-signer 'https://signer.frontiercrown.com/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "com-frontiercrown-signer-nostr-signer": {
      "url": "https://signer.frontiercrown.com/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "com-frontiercrown-signer-nostr-signer": {
      "type": "http",
      "url": "https://signer.frontiercrown.com/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.com-frontiercrown-signer-nostr-signer]
url = "https://signer.frontiercrown.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-frontiercrown-signer-nostr-signer": {
      "type": "remote",
      "url": "https://signer.frontiercrown.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-frontiercrown-signer-nostr-signer --url 'https://signer.frontiercrown.com/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-frontiercrown-signer-nostr-signer:
    url: "https://signer.frontiercrown.com/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "com-frontiercrown-signer-nostr-signer": {
      "Transport": "http",
      "Url": "https://signer.frontiercrown.com/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add com-frontiercrown-signer-nostr-signer -t streamable-http -u 'https://signer.frontiercrown.com/mcp'
```

### Other

```json
{
  "mcpServers": {
    "com-frontiercrown-signer-nostr-signer": {
      "type": "http",
      "url": "https://signer.frontiercrown.com/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-28 (score 69, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-26 (score 68, +1)

No change was recorded against any check on this day. Stability & Change Management went from 35 to 39.

### 2026-09-25 (score 67, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-23 (score 67, +1)

No change was recorded against any check on this day. Stability & Change Management went from 25 to 29.

### 2026-09-21 (score 66, +1)

No change was recorded against any check on this day. Stability & Change Management went from 19 to 22.

### 2026-09-19 (score 65, +1)

No change was recorded against any check on this day. Stability & Change Management went from 12 to 15.

### 2026-09-17 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 5 to 9.

### 2026-09-15 (score 63, +1)

No change was recorded against any check on this day. Stability & Change Management went from 0 to 2.

## MCP tools (17)

### `get_setup_url` (~34 tokens)

Get signer setup URL

Return the loopback-only page used to connect a NIP-07 browser extension or an advanced NIP-46 signer.

### `get_signer_status` (~28 tokens)

Get signer status

Check whether a user-controlled NIP-07 or NIP-46 signer is connected.

### `begin_nostrconnect_pairing` (~48 tokens)

Begin signer pairing

Advanced fallback: create a nostrconnect:// URI for the user to scan or open in a remote signer. Never accepts an nsec.

Input parameters:

- `relays` (array)

### `connect_bunker` (~50 tokens)

Connect bunker signer

Connect 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.

Input parameters:

- `connection_uri` (string, required)

### `get_public_key` (~20 tokens)

Get public key

Return the public key exposed by the currently paired signer.

### `prepare_note` (~36 tokens)

Prepare Nostr note

Prepare and bind an exact unsigned kind:1 note for user review. This does not sign or publish.

Input parameters:

- `content` (string, required)

### `prepare_event` (~45 tokens)

Prepare exact Nostr event

Validate 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.

Input parameters:

- `event` (object, required)

### `sign_event` (~60 tokens)

Request event signature

Ask the paired signer to approve and sign the exact event bound to a fresh intent. Requires explicit user intent and never publishes.

Input parameters:

- `confirm_signature` (boolean, required): Must be true only after the user explicitly approved this action.
- `intent_id` (string, required)

### `publish_event` (~60 tokens)

Publish signed event

Publish a previously verified signed event to configured relays. Requires separate explicit user intent.

Input parameters:

- `confirm_publish` (boolean, required): Must be true only after the user explicitly approved this action.
- `intent_id` (string, required)
- `relays` (array)

### `query_events` (~60 tokens)

Read Nostr events

Read a bounded set of verified public profile or note events from selected relays.

Input parameters:

- `authors` (array)
- `kinds` (array)
- `limit` (integer)
- `relays` (array)
- `since` (integer)

### `disconnect_signer` (~39 tokens)

Disconnect signer

Forget the in-memory signer session and all prepared events.

Input parameters:

- `confirm_disconnect` (boolean, required): Must be true only after the user explicitly approved this action.

### `get_grynvault_account_dashboard` (~75 tokens)

Get signed Grynvault account dashboard

Read 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.

Input parameters:

- `confirm_account_access` (boolean, required): Must be true only after the user approved signing a read-only Grynvault account request.

### `approve_grynvault_browser_handoff` (~117 tokens)

Approve Grynvault in-app browser sign-in

Sign 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.

Input parameters:

- `code` (string, required): The one-time code displayed by the Grynvault portal, for example ABCD-EFGH-JKLM.
- `confirm_browser_sign_in` (boolean, required): Must be true only after the user asked to sign the displayed Grynvault browser code.

### `prepare_grynvault_supporter_invoice` (~82 tokens)

Prepare Grynvault supporter invoice

Prepare 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.

Input parameters:

- `donation_sats` (integer)
- `plan` (string, required)

### `create_grynvault_supporter_invoice` (~74 tokens)

Create Grynvault supporter invoice

After 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.

Input parameters:

- `confirm_invoice_creation` (boolean, required): Must be true only after the user explicitly approved this action.
- `operation_id` (string, required)

### `prepare_grynvault_nip05_invoice` (~64 tokens)

Prepare Frontier Crown NIP-05 invoice

Check 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.

Input parameters:

- `name` (string, required)

### `create_grynvault_nip05_invoice` (~84 tokens)

Create Frontier Crown NIP-05 invoice

After 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.

Input parameters:

- `confirm_invoice_creation` (boolean, required): Must be true only after the user explicitly approved this action.
- `operation_id` (string, required)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-frontiercrown-signer-nostr-signer/signer#diagnostics

## Score history

- 2026-09-28: 69
- 2026-09-27: 68
- 2026-09-26: 68
- 2026-09-25: 67
- 2026-09-24: 67
- 2026-09-23: 67
- 2026-09-22: 66
- 2026-09-21: 66
- 2026-09-20: 65
- 2026-09-19: 65
- 2026-09-18: 64
- 2026-09-17: 64
- 2026-09-16: 63
- 2026-09-15: 63
- 2026-09-14: 62
- 2026-09-13: 62
- 2026-09-12: 62
- 2026-09-11: 62

## Common questions

### What is the Nostr Signer MCP server?

Nostr Signer is an MCP server listed in the public MCP registry as com.frontiercrown.signer/nostr-signer. Approve Nostr signatures with your own browser signer without exposing a private key. This page covers its hosted endpoint (https://signer.frontiercrown.com/mcp).

### Is the Nostr Signer MCP server safe to use?

Nostr Signer scores 69 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the Nostr Signer MCP server expose?

Nostr Signer exposes 17 tools: get_setup_url, get_signer_status, begin_nostrconnect_pairing, connect_bunker, get_public_key, and 12 more. Their descriptions and schemas cost roughly 976 tokens of context every time the server is loaded.

### Does the Nostr Signer MCP server require authentication?

No. We connected to Nostr Signer without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Nostr Signer MCP server still maintained?

Nostr Signer is still listed as active in the MCP registry. We last reached this channel on 28 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://signer.frontiercrown.com/mcp
- Repository: https://github.com/hudhaifahz/nostr-signer-chatgpt
- Changelog RSS feed: https://verifymcp.io/servers/com-frontiercrown-signer-nostr-signer/signer.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-frontiercrown-signer-nostr-signer/signer.json
- HTML version of this page: https://verifymcp.io/servers/com-frontiercrown-signer-nostr-signer/signer