signNote · Nostr Tools for AI Agents MCP: Risk & Policy

WHAT IT DOES

What signNote does on Nostr Tools for AI Agents

AI agents invoke signNote to trigger actions in Nostr Tools for AI Agents. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why signNote needs a policy

Signing a note is more than a read operation; it performs a cryptographic action that produces an authenticated artifact ready to be broadcast to the Nostr network. While signing alone doesn't publish, it is a prerequisite step in the publish pipeline and constitutes executing an external operation.

From the tool's definition 'Sign a note event' — signing triggers a cryptographic operation that authenticates and prepares a Nostr event for publication, representing an external operation with real effects when combined with publishing.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

signNote Rate-limited

signNote stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "signNote": {
      "limits": [
        {
          "counter": "signnote_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Nostr Tools for AI Agents, so you can run agents against it safely.

FAQ

Questions about signNote

What does the signNote tool do? +

Sign a note event. It is categorised as a Execute tool in the Nostr Tools for AI Agents MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on signNote? +

Register the Nostr Tools for AI Agents MCP server in PolicyLayer and add a rule for signNote: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Nostr Tools for AI Agents. Nothing to install.

What risk level is signNote? +

signNote is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit signNote? +

Yes. Add a rate_limit block to the signNote rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block signNote completely? +

Set action: deny in the PolicyLayer policy for signNote. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides signNote? +

signNote is provided by the Nostr Tools for AI Agents MCP server (jorgenclaw/nostr-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.