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 behavioral traits like returning 'a week overview with events organized by day, total event count, and busiest day indicator,' which adds value beyond the input schema. However, it doesn't cover aspects like authentication needs, rate limits, error handling, or whether it's read-only (implied by 'Get' but not stated). The description doesn't contradict any annotations, as there are none.

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 appropriately sized and front-loaded: the first sentence states the core purpose, followed by details on the return format and usage context. Every sentence earns its place by adding value—no redundancy or waste. It's concise yet informative, making it easy for an AI agent to parse quickly.

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 (2 parameters, no output schema, no annotations), the description is somewhat complete but has gaps. It explains what the tool does and the return format, which is helpful since there's no output schema. However, it lacks details on behavioral aspects like error cases or performance, and it doesn't fully address usage compared to siblings. This makes it adequate but not fully comprehensive for the context.

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 input schema fully documents the two parameters (start_date and calendar_ids). The description doesn't add any parameter-specific information beyond what's in the schema, such as examples or constraints. According to the rules, with high schema coverage (>80%), the baseline is 3 even with no param info in the description, which applies here.

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: 'Get a summary of events for the upcoming 7 days.' It specifies the verb ('Get a summary') and resource ('events'), and distinguishes it from siblings like calendar_daily_agenda (daily vs weekly) and calendar_list_events (list vs summary). However, it doesn't explicitly contrast with all siblings (e.g., calendar_search), keeping it from a perfect score.

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 implies usage context with 'Useful for weekly planning,' which suggests when to use this tool. It doesn't explicitly state when not to use it or name alternatives among siblings, such as using calendar_daily_agenda for daily details or calendar_list_events for raw event lists. This provides some guidance but lacks explicit exclusions or comparisons.

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