Check if a time slot is free or busy
AI agents call check_availability to retrieve information from AI Calendar Assistant without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves calendar state (availability) with no side effects. It does not create, modify, delete, or execute code. The sibling tools (create_event, delete_event, update_event) are more severe; this one only queries. Severity is low because misuse (e.g., checking another user's calendar repeatedly) poses minimal blast radius compared to event manipulation or destruction.
From the tool's definition Tool description states 'Check if a time slot is free or busy' — a read-only query operation that retrieves calendar availability information without modifying, deleting, or executing external operations.
Attacks that exploit this kind of access
Check if a time slot is free or busy. It is categorised as a Read tool in the AI Calendar Assistant MCP Server, which means it retrieves data without modifying state.
Register the AI Calendar Assistant MCP server in PolicyLayer and add a rule for check_availability: 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 AI Calendar Assistant. Nothing to install.
check_availability 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 check_availability 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 check_availability. 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.
check_availability is provided by the AI Calendar Assistant MCP server (othmane-zizi-pro/ai-calendar-assistant). 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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