calendar_update · Mariana Google MCP: Risk & Policy

WHAT IT DOES

What calendar_update does on Mariana Google MCP

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

WHY IT NEEDS A POLICY

Why calendar_update needs a policy

This tool creates or modifies calendar data reversibly. It does not delete (which would be Destructive), does not execute arbitrary code (which would be Execute), and does not move money (which would be Financial). The reversible nature of calendar updates and the safety measure of not auto-notifying attendees keep this in Write category.

From the tool's definition Tool name is 'calendar_update' and description states 'Modify an existing calendar event', which is a reversible data modification operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

calendar_update Rate-limited

calendar_update 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_update": {
      "limits": [
        {
          "counter": "calendar_update_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 Mariana Google MCP, so you can run agents against it safely.

FAQ

Questions about calendar_update

What does the calendar_update tool do? +

Modify an existing calendar event. Does NOT notify attendees by default. It is categorised as a Write tool in the Mariana Google MCP 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_update? +

Register the Mariana Google MCP server in PolicyLayer and add a rule for calendar_update: 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 Mariana Google MCP. Nothing to install.

What risk level is calendar_update? +

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

Can I rate-limit calendar_update? +

Yes. Add a rate_limit block to the calendar_update 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_update completely? +

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

calendar_update is provided by the Mariana Google MCP server (marianasmall/mariana-google-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.