Send a message to all members of a contact group. Messages are sent as individual encrypted DMs with group context.
AI agents use crow_send_group_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.
This tool creates messages (write operation) but does not delete, execute arbitrary code, move funds, or trigger uncontrolled external operations. While the blast radius of sending unwanted mass messages to contact groups could be moderate (spam, disclosure of sensitive information to unintended recipients), it is reversible—messages can be recalled or groups can be managed.
From the tool's definition Tool description states it will "Send a message to all members of a contact group," which is a write operation that creates/modifies data (messages) in a communications system.
Documented attack patterns abuse exactly the kind of access crow_send_group_message gives an agent:
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_send_group_message:
{
"version": "1",
"default": "deny",
"tools": {
"crow_send_group_message": {
"limits": [
{
"counter": "crow_send_group_message_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}crow_send_group_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.
Free to start. No card required.
Send a message to all members of a contact group. Messages are sent as individual encrypted DMs with group context. 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.
Register the Crow MCP server in PolicyLayer and add a rule for crow_send_group_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.
crow_send_group_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the crow_send_group_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.
Set action: deny in the PolicyLayer policy for crow_send_group_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.
crow_send_group_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.
Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
576 Crow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.