List all available calendars
AI agents call list-calendars to retrieve information from Google Calendar MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves calendar metadata without side effects. It falls clearly into the Read category as it only lists existing calendars without creating, modifying, or deleting data. The blast radius of misuse is minimal—an agent could at most enumerate calendars the authenticated user has access to, which is informational only.
From the tool's definition Tool name 'list-calendars' and description 'List all available calendars' indicate a retrieval operation with no modification, deletion, or execution of external commands.
Attacks that exploit this kind of access
List all available calendars. It is categorised as a Read tool in the Google Calendar MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Google Calendar MCP Server MCP server in PolicyLayer and add a rule for 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 Google Calendar MCP Server. Nothing to install.
list-calendars is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the 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.
Set action: deny in the PolicyLayer policy for 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.
list-calendars is provided by the Google Calendar MCP Server MCP server (progrmoiz/cal-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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