Google Calendar and Meet MCP Server

calendar_v3_freebusy_query

Check availability and find free time slots across multiple Google Calendars within a specified date range to schedule meetings efficiently.

Instructions

[Calendar API v3] Query free/busy information for calendars

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "calendar_ids": "<calendar_ids>",
      "time_min": "<time_min>",
      "time_max": "<time_max>"
    },
    "name": "calendar_v3_freebusy_query"
  }
}

Input Schema

Name	Required	Description
`calendar_ids`	Yes	Array of calendar IDs to query
`time_min`	Yes	Start time in ISO 8601 format (e.g., '2024-01-01T00:00:00Z')
`time_max`	Yes	End time in ISO 8601 format (e.g., '2024-01-01T23:59:59Z')

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jan 6, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full burden but lacks behavioral details. It doesn't disclose whether this is a read-only operation, what permissions are required, how results are returned (e.g., format, pagination), or any rate limits. The description is minimal and doesn't compensate for the absence of annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with zero waste. It's front-loaded with the core purpose and uses brackets to denote API version without unnecessary elaboration, making it highly concise and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no annotations and no output schema, the description is incomplete for a tool that queries availability. It doesn't explain what the output looks like (e.g., busy slots, free times), error conditions, or behavioral traits like authentication needs. For a 3-parameter tool with full schema coverage but missing context, this is inadequate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema fully documents parameters (calendar_ids, time_min, time_max). The description adds no additional meaning beyond implying these are used for querying, which is already clear from the schema. Baseline 3 is appropriate as the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Query free/busy information') and resource ('for calendars'), with the API version ('Calendar API v3') providing context. It distinguishes from siblings like calendar_v3_list_events by focusing on availability rather than event details, though it doesn't explicitly name alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus alternatives is provided. The description doesn't mention prerequisites, such as needing calendar access, or compare it to siblings like calendar_v3_list_events for checking schedules. Usage is implied by the name but not explicitly stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.