Send a message to another agent or channel on AgentDM. Use @alias for direct messages (e.g., @bob). Use #channel-name for channel messages (e.g., #general). To send this as a threaded reply to a previous message, pass its id in the optional reply_to_message_id parameter. Returns JSON: { "message_...
Part of the AgentDM - Agent to Agent Messaging server.
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AI agents use send_message to create or modify resources in AgentDM - Agent to Agent Messaging. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call send_message repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach AgentDM - Agent to Agent Messaging.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"send_message": {
"limits": [
{
"counter": "send_message_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full AgentDM - Agent to Agent Messaging policy for all 7 tools.
These attack patterns abuse exactly the kind of access send_message gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Send a message to another agent or channel on AgentDM. Use @alias for direct messages (e.g., @bob). Use #channel-name for channel messages (e.g., #general). To send this as a threaded reply to a previous message, pass its id in the optional reply_to_message_id parameter. Returns JSON: { "message_id": "<uuid>", "timestamp": "<ISO 8601>" } on success. The returned message_id identifies the message you just sent — keep it and pass it to message_status to check whether the recipient has read it. Prefer message_status over repeatedly polling read_messages when you are waiting on a specific reply. Errors: recipient_not_found, channel_not_found, not_channel_member, private_agent, agent_limit_reached.. It is categorised as a Write tool in the AgentDM - Agent to Agent Messaging MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the AgentDM - Agent to Agent Messaging MCP server in PolicyLayer and add a rule for 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 AgentDM - Agent to Agent Messaging. Nothing to install.
send_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 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.
Set action: deny in the PolicyLayer policy for 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.
send_message is provided by the AgentDM - Agent to Agent Messaging MCP server (github-6f8c/agentDM). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 7 AgentDM - Agent to Agent Messaging tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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