Google Calendar MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions what the tool returns ('Returns busy time slots') but doesn't cover important aspects like authentication requirements, rate limits, error conditions, or whether this is a read-only operation (though implied by 'Check'). The behavioral context is incomplete for a tool that queries calendar data.

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

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

The description is perfectly concise with three sentences that each add value: states the core function, specifies the return value, and provides usage context. No wasted words, and the information is front-loaded with the primary purpose first.

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

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

For a tool with 3 parameters, 100% schema coverage, but no annotations and no output schema, the description provides basic functional context but lacks details about return format, error handling, or operational constraints. It's minimally adequate but leaves gaps that could hinder effective tool selection and invocation.

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

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

Schema description coverage is 100%, so the schema already fully documents all three parameters. The description adds no additional parameter information beyond what's in the schema. The baseline score of 3 reflects adequate parameter documentation through the schema alone.

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

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

The description clearly states the tool's purpose with specific verbs ('Check free/busy status') and resources ('for one or more calendars'), and distinguishes it from siblings by focusing on availability rather than event management. However, it doesn't explicitly differentiate from all siblings like 'calendar_list_events' which also deals with calendar data.

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

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

The description provides implied usage context ('Useful for finding available meeting times') which suggests when to use it, but lacks explicit guidance on when to choose this tool over alternatives like 'calendar_list_events' or 'calendar_search'. No exclusions or prerequisites are mentioned.

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