Google Calendar MCP Server

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

No annotations are provided, so the description carries the full burden. It discloses the tool's behavior by describing the output format ('formatted summary... organized by all-day events and timed events') and its utility ('Useful for daily briefings'), which adds value beyond the schema. However, it lacks details on permissions, rate limits, or error handling, which are important for a read operation with no annotations.

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 front-loaded with the core purpose in the first sentence, followed by details on the return format and utility. Every sentence earns its place by adding value—no redundant or vague statements. It's efficiently structured in three concise sentences, making it easy to parse.

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?

Given the tool's moderate complexity (a read operation with 2 optional parameters), no annotations, and no output schema, the description is fairly complete. It covers the purpose, output format, and use case, but could improve by mentioning potential limitations (e.g., default behavior if parameters are omitted) or linking to sibling tools for broader context. It's adequate but has minor gaps in full contextual coverage.

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 both parameters (date and calendar_ids). The description does not add any parameter-specific information beyond what the schema provides, such as examples or constraints. With high schema coverage, the baseline score of 3 is appropriate, as the description doesn't compensate but also doesn't detract.

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 specific action ('Get the agenda') and resource ('for a specific day with all events'), distinguishing it from siblings like calendar_list_events (which lists events generally) or calendar_weekly_summary (which covers a week). It explicitly mentions the output format ('formatted summary... organized by all-day events and timed events'), making the purpose distinct and well-defined.

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 clear context for when to use this tool ('Useful for daily briefings'), but it does not explicitly state when not to use it or name alternatives. For example, it doesn't contrast with calendar_list_events for broader event queries or calendar_weekly_summary for weekly overviews, leaving some ambiguity in tool selection.

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