add_site_permission · Microsoft Graph MCP Server MCP

WHAT IT DOES

What add_site_permission does on Microsoft Graph MCP Server

AI agents use add_site_permission 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_site_permission needs a policy

This tool modifies access control lists (ACLs) or permission records on a SharePoint site by adding a user permission. While it creates/modifies data rather than executing arbitrary code or deleting resources, it has significant blast radius because incorrect permission grants could expose sensitive organizational data or grant unauthorized access.

From the tool's definition Tool name 'add_site_permission' and description 'Add a user permission to a SharePoint site' indicate creation/modification of access control settings. This creates a new permission entry that grants access rights to a SharePoint resource.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_site_permission Rate-limited

add_site_permission 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_site_permission": {
      "limits": [
        {
          "counter": "add_site_permission_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_site_permission

What does the add_site_permission tool do? +

Add a user permission to a SharePoint site. 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_site_permission? +

Register the Microsoft Graph MCP Server MCP server in PolicyLayer and add a rule for add_site_permission: 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_site_permission? +

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

Can I rate-limit add_site_permission? +

Yes. Add a rate_limit block to the add_site_permission 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_site_permission completely? +

Set action: deny in the PolicyLayer policy for add_site_permission. 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_site_permission? +

add_site_permission 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.