contact_add_to_list · M365 MCP: Risk & Policy

WHAT IT DOES

What contact_add_to_list does on M365

AI agents use contact_add_to_list to create or update resources in M365 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your M365 environment.

WHY IT NEEDS A POLICY

Why contact_add_to_list needs a policy

Adding a contact to a list is a reversible write operation that creates or modifies contact group membership. It does not delete data (would be Destructive), execute arbitrary code (would be Execute), move money (Financial), or merely read (Read).

From the tool's definition Tool name 'contact_add_to_list' indicates adding contacts to a list, which modifies contact group/list membership. The 'm365-mcp' server manages Microsoft 365 Contacts. No description provided, but the naming pattern clearly shows a modification operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

contact_add_to_list Rate-limited

contact_add_to_list 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": {
    "contact_add_to_list": {
      "limits": [
        {
          "counter": "contact_add_to_list_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 M365, so you can run agents against it safely.

FAQ

Questions about contact_add_to_list

What does the contact_add_to_list tool do? +

contact_add_to_list. It is categorised as a Write tool in the M365 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on contact_add_to_list? +

Register the M365 MCP server in PolicyLayer and add a rule for contact_add_to_list: 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 M365. Nothing to install.

What risk level is contact_add_to_list? +

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

Can I rate-limit contact_add_to_list? +

Yes. Add a rate_limit block to the contact_add_to_list 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 contact_add_to_list completely? +

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

contact_add_to_list is provided by the M365 MCP server (robin-collins/m365-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.