query_free_busy
Returns the busy intervals of up to 50 calendars in one time window — the way to find a common free slot before create_event. Input calendar ids (or attendee email addresses, which double as their primary-calendar ids — subject to their sharing settings). The response maps each calendar id to bus...
This record as markdown: /tools/a1-x-tech-mcp-google-calendar/query-free-busy.md
What query_free_busy does on Mcp Google Calendar
AI agents call query_free_busy to retrieve information from Mcp Google Calendar without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
time_max | string | Yes | Window end, RFC3339. |
time_min | string | Yes | Window start, RFC3339. |
time_zone | string | — | IANA zone the busy times are rendered in (default UTC). |
calendar_ids | array | Yes | Calendar ids to check (1..50) — "primary", calendar ids from list_calendars, or attendee emails. |
Parameters from the server's own tool schema.
Why query_free_busy is rated Low
Even though query_free_busy only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs query_free_busy safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Google Calendar, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For query_free_busy, this is the rule to start with:
query_free_busy is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Google Calendar, apply this rule, and every query_free_busy call is checked against it from then on.
Questions about query_free_busy
Returns the busy intervals of up to 50 calendars in one time window — the way to find a common free slot before create_event. Input calendar ids (or attendee email addresses, which double as their primary-calendar ids — subject to their sharing settings). The response maps each calendar id to busy:[{start,end}] ranges; gaps between them are free. Only busy blocks come back — never event titles or details — and events marked transparent (free) don't appear. A calendar the user cannot read shows up under errors, not busy. This is a pure read despite being an HTTP POST. It is categorised as a Read tool in the Mcp Google Calendar MCP Server, which means it retrieves data without modifying state.
query_free_busy accepts 4 parameters: time_max, time_min, time_zone, calendar_ids. Required: time_max, time_min, calendar_ids. The full parameter table on this page comes from the server's own tool schema.
Register the Mcp Google Calendar MCP server in PolicyLayer and add a rule for query_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 Mcp Google Calendar. Nothing to install.
query_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 query_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 query_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.
query_free_busy is provided by the Mcp Google Calendar MCP server (@a1-x-tech/mcp-google-calendar). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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