crow_send_message

Send an encrypted message via the Nostr network. Messages cannot be retracted once sent.

SERVERCrow SOURCEkh0pper/crow

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/kh0pper-crow/crow-send-message.md

WHAT IT DOES

What crow_send_message does on Crow

AI agents use crow_send_message to create or update resources in Crow, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Crow environment.

RISK

Why crow_send_message is rated Medium

This tool creates new data (a message) in a persistent external system (Nostr network). While messages cannot be deleted post-send, the primary action is Write (creation/transmission of data), not Destructive (deletion/overwriting). The irretrievability is a characteristic of the platform, not an inherent destructive action by this tool.

From the tool's definition "Send an encrypted message via the Nostr network. Messages cannot be retracted once sent." — explicitly sends/posts data to an external network with permanent effect.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs crow_send_message safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For crow_send_message, this is the rule to start with:

crow_send_message Rate-limited

crow_send_message stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "crow_send_message": {
      "limits": [
        {
          "counter": "crow_send_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every crow_send_message call is checked against it from then on.

FAQ

Questions about crow_send_message

What does the crow_send_message tool do? +

Send an encrypted message via the Nostr network. Messages cannot be retracted once sent. It is categorised as a Write tool in the Crow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on crow_send_message? +

Register the Crow MCP server in PolicyLayer and add a rule for crow_send_message: 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 Crow. Nothing to install.

What risk level is crow_send_message? +

crow_send_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit crow_send_message? +

Yes. Add a rate_limit block to the crow_send_message 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 crow_send_message completely? +

Set action: deny in the PolicyLayer policy for crow_send_message. 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 crow_send_message? +

crow_send_message is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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