calendar_propose_new_time · M365 MCP: Risk & Policy

WHAT IT DOES

What calendar_propose_new_time does on M365

AI agents use calendar_propose_new_time 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 calendar_propose_new_time needs a policy

Based on the tool name, this likely sends a counter-proposal for a new meeting time to calendar event participants, which is a write/modify action on calendar data. However, the empty description significantly lowers confidence. It could also trigger notifications to other users, making it closer to Execute, but Write is most probable given the naming convention and sibling tools context.

From the tool's definition Tool name 'calendar_propose_new_time' suggests modifying or responding to a calendar event by proposing a new meeting time. Description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

calendar_propose_new_time Rate-limited

calendar_propose_new_time 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": {
    "calendar_propose_new_time": {
      "limits": [
        {
          "counter": "calendar_propose_new_time_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 calendar_propose_new_time

What does the calendar_propose_new_time tool do? +

calendar_propose_new_time. 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 calendar_propose_new_time? +

Register the M365 MCP server in PolicyLayer and add a rule for calendar_propose_new_time: 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 calendar_propose_new_time? +

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

Can I rate-limit calendar_propose_new_time? +

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

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

calendar_propose_new_time 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.