teams_send_channel_message · Microsoft Teams MCP

WHAT IT DOES

What teams_send_channel_message does on Microsoft Teams

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

WHY IT NEEDS A POLICY

Why teams_send_channel_message needs a policy

This tool creates and posts new content to a collaborative workspace. While messages can theoretically be deleted, the primary action is to write/create data in a persistent, shared system. It is not Destructive because message creation is reversible through normal Teams deletion workflows.

From the tool's definition Tool description states 'Send a message to a Teams channel' — this creates new data (a message) in a shared channel, modifying the channel's message history irreversibly from the perspective of the channel's state, though the message itself can be edited or…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

teams_send_channel_message Rate-limited

teams_send_channel_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": {
    "teams_send_channel_message": {
      "limits": [
        {
          "counter": "teams_send_channel_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Microsoft Teams, so you can run agents against it safely.

FAQ

Questions about teams_send_channel_message

What does the teams_send_channel_message tool do? +

Send a message to a Teams channel. Supports plain text and HTML. It is categorised as a Write tool in the Microsoft Teams MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on teams_send_channel_message? +

Register the Microsoft Teams MCP server in PolicyLayer and add a rule for teams_send_channel_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 Microsoft Teams. Nothing to install.

What risk level is teams_send_channel_message? +

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

Can I rate-limit teams_send_channel_message? +

Yes. Add a rate_limit block to the teams_send_channel_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 teams_send_channel_message completely? +

Set action: deny in the PolicyLayer policy for teams_send_channel_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 teams_send_channel_message? +

teams_send_channel_message is provided by the Microsoft Teams MCP server (microsoft-teams-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.