Fitbit Daily Heart Rate

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

Annotations already indicate read-only, non-destructive, idempotent behavior. Description adds value by disclosing the required OAuth scope and stating it's not medical advice, which goes beyond annotations. No contradictions.

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?

Three short, front-loaded sentences with no wasted words. Essential information is presented efficiently.

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?

With a rich output schema and comprehensive annotations, the description sufficiently covers usage. Minor gap: no mention of pagination or data range limits, but not critical for this simple daily tool.

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?

Input schema parameter descriptions are clear for date and privacy_mode, though response_format only has default and enum. Description adds no additional meaning beyond what the schema provides; baseline score 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?

Description clearly states it retrieves daily heart-rate zones and resting heart rate, distinguishing it from intraday and other heart-related tools like fitbit_get_heart_intraday. The title 'Fitbit Daily Heart Rate' reinforces the scope.

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?

Description mentions required 'heartrate scope' and disclaims medical advice, but does not explicitly guide when to use this tool versus alternatives like fitbit_get_heart_intraday or other daily health metrics. Usage context is implied but not explicit.

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