add_user_to_group · Microsoft Graph MCP Server MCP

WHAT IT DOES

What add_user_to_group does on Microsoft Graph MCP Server

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

WHY IT NEEDS A POLICY

Why add_user_to_group needs a policy

This tool creates or modifies organizational access by adding a user to a group. While reversible (hence Write rather than Destructive), it has high blast radius because it grants immediate access to group-connected resources including SharePoint sites. An AI agent misusing this could grant unauthorized access to sensitive organizational data or resources.

From the tool's definition "Add a user to a group (also grants access to group-connected SharePoint sites)" - modifies group membership and access permissions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_user_to_group Rate-limited

add_user_to_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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_user_to_group": {
      "limits": [
        {
          "counter": "add_user_to_group_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 Graph MCP Server, so you can run agents against it safely.

FAQ

Questions about add_user_to_group

What does the add_user_to_group tool do? +

Add a user to a group (also grants access to group-connected SharePoint sites). It is categorised as a Write tool in the Microsoft Graph MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_user_to_group? +

Register the Microsoft Graph MCP Server MCP server in PolicyLayer and add a rule for add_user_to_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 Microsoft Graph MCP Server. Nothing to install.

What risk level is add_user_to_group? +

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

Can I rate-limit add_user_to_group? +

Yes. Add a rate_limit block to the add_user_to_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 add_user_to_group completely? +

Set action: deny in the PolicyLayer policy for add_user_to_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 add_user_to_group? +

add_user_to_group is provided by the Microsoft Graph MCP Server MCP server (ry-ops/microsoft-graph-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.