get_glucose_readings

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 clearly states the tool uses an 'unofficial Share API' and only provides 'real-time monitoring data', which is valuable context about limitations. However, it does not mention potential errors or rate limits, but the critical constraint is well covered.

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 concise and front-loaded with the purpose, followed by the key constraint and limitation. Every sentence adds value without waste.

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 simplicity (2 parameters, no output schema, no nested objects), the description is sufficient to guide correct usage and set expectations. It could mention return format but that is not critical for a simple data retrieval. The limitation is well articulated.

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?

The input schema already provides descriptions for both parameters with ISO format examples and the 24-hour constraint. The description reinforces this but adds minimal new meaning beyond that. With 100% schema coverage, a baseline of 3 is appropriate.

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 states the tool retrieves 'recent glucose values within the last 24 hours', which is a specific verb+resource+time scope. It clearly distinguishes from the sibling 'get_latest_reading' by emphasizing the time range and use of the Share API.

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 explicitly warns that both startDate and endDate must be within the last 24 hours, and that the tool cannot retrieve historical data beyond that window. This provides clear when-to-use guidance and implicitly differentiates from the sibling for the latest reading.

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