Get aggregated availability across all calendars. Returns busy times, free slots, and optionally suggests meeting times of requested duration.
AI agents call get_free_busy to retrieve information from 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 aggregates and queries calendar availability data across multiple providers but performs no write operations, deletions, code execution, or financial transactions. It is a read-only data retrieval function that presents scheduling information to help users identify available time slots. No side effects or irreversible changes occur.
From the tool's definition Tool description explicitly states it 'returns busy times, free slots' and 'suggests meeting times' — purely informational retrieval operations with no modification, deletion, or execution of external commands.
Attacks that exploit this kind of access
Get aggregated availability across all calendars. Returns busy times, free slots, and optionally suggests meeting times of requested duration. It is categorised as a Read tool in the Calendar MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Calendar MCP Server MCP server in PolicyLayer and add a rule for get_free_busy: 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 Calendar MCP Server. Nothing to install.
get_free_busy 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 get_free_busy 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 get_free_busy. 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.
get_free_busy is provided by the Calendar MCP Server MCP server (rauf543/calendar-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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