calendar_list_calendars

THE RISK

Low Risk

Why calendar_list_calendars needs a policy

This tool retrieves and queries calendar data without side effects. It is a read-only operation that enumerates available calendars for the authenticated user. No data is created, modified, deleted, or executed. The operation has minimal blast radius even if misused by an AI agent, as it only exposes metadata about calendar availability.

From the tool's definition Tool name contains 'list' and description states 'List all Synology Calendar calendars accessible to the authenticated user' with no modification, deletion, or execution capabilities.

Documented attack patterns abuse exactly the kind of access calendar_list_calendars gives an agent:

POLICY

How to control calendar_list_calendars

PolicyLayer is an MCP gateway — it sits between your AI agents and Synology Office, and nothing reaches the server without passing your rules. This is the rule we recommend for calendar_list_calendars:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "calendar_list_calendars": {}
  }
}

calendar_list_calendars is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Synology Office — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Synology Office tools

Destructive calendar_delete_event Delete a Synology Calendar event permanently. Requires confirm=true. Destructive drive_delete_file Delete a file or folder in Synology Drive (moves to trash by default). Set confirm=true to Destructive spreadsheet_delete_file WARNING: Permanently delete an ENTIRE spreadsheet file (.osheet). Destructive spreadsheet_delete_sheet Delete a sheet tab from a Synology Spreadsheet. This action cannot be undone. Provide eith Write spreadsheet_append_rows Append rows to the end of existing data in a Synology Spreadsheet sheet. Provide either fi Write drive_get_sharing_link Generate or retrieve a sharing link for a Synology Drive file with configurable permission Write calendar_create_calendar Create a new Synology Calendar. Write calendar_create_event Create a new Synology Calendar event. Requires confirm=true.

All 39 Synology Office tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about calendar_list_calendars

What does the calendar_list_calendars tool do? +

List all Synology Calendar calendars accessible to the authenticated user. It is categorised as a Read tool in the Synology Office MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on calendar_list_calendars? +

Register the Synology Office MCP server in PolicyLayer and add a rule for calendar_list_calendars: 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 Synology Office. Nothing to install.

What risk level is calendar_list_calendars? +

calendar_list_calendars is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit calendar_list_calendars? +

Yes. Add a rate_limit block to the calendar_list_calendars 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_list_calendars completely? +

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

calendar_list_calendars is provided by the Synology Office MCP server (vocweb/synology-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Synology Office tool call.

Start from Synology Office, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →