Post message to active meeting or global chat.
AI agents use send_message to create or update resources in N2n Nexus — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your N2n Nexus environment.
This tool creates new message data in a chat or meeting context. It is reversible (messages can typically be edited or deleted by other means) and has no side effects beyond storing text communication. It is not destructive, does not execute code or external operations, and poses minimal risk even if misused by an AI agent—at worst, unwanted messages would be sent, which is a low-impact write operation.
From the tool's definition Tool description states 'Post message to active meeting or global chat' — the verb 'Post' and the action of adding a message to a chat or meeting indicates data creation/modification.
Documented attack patterns abuse exactly the kind of access send_message gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and N2n Nexus, and nothing reaches the server without passing your rules. This is the rule we recommend for send_message:
{
"version": "1",
"default": "deny",
"tools": {
"send_message": {
"limits": [
{
"counter": "send_message_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}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.
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Post message to active meeting or global chat. It is categorised as a Write tool in the N2n Nexus MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the N2n Nexus 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 N2n Nexus. 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 N2n Nexus MCP server (n2ns/n2n-nexus). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from N2n Nexus, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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22 N2n Nexus tools catalogued and risk-classified — across an index of 43,000+ MCP servers.