crow_create_message_group

THE RISK

Medium Risk

Why crow_create_message_group needs a policy

This tool creates a new message group, which is a reversible write operation. There are no destructive, financial, or code execution aspects. The impact is localized to creating a new collaborative communication container. Severity is low because misuse would simply result in unwanted message groups that can be deleted or ignored.

From the tool's definition Tool name includes 'create' and description states 'Create a message group' — creates a new reversible data structure (message group) without deletion or financial implications.

Documented attack patterns abuse exactly the kind of access crow_create_message_group gives an agent:

POLICY

How to control crow_create_message_group

PolicyLayer is an MCP gateway — it sits between your AI agents and Crow, and nothing reaches the server without passing your rules. This is the rule we recommend for crow_create_message_group:

policy.json

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

crow_create_message_group 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.

Create a free account and register Crow — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about crow_create_message_group

What does the crow_create_message_group tool do? +

Create a message group for group conversations. Add contacts by name or Crow ID. 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_create_message_group? +

Register the Crow MCP server in PolicyLayer and add a rule for crow_create_message_group: 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_create_message_group? +

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

Can I rate-limit crow_create_message_group? +

Yes. Add a rate_limit block to the crow_create_message_group 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_create_message_group completely? +

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

crow_create_message_group 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.

Enforce policy on every Crow tool call.

Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →