Fitbit Daily SpO2

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

Annotations already provide read-only, idempotent, and open-world hints. The description adds the authentication scope requirement and a disclaimer, which are beyond annotations. However, it does not disclose behavior like data unavailability handling or rate limits.

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?

Two concise sentences that immediately convey action and prerequisites. No filler or redundancy. Front-loading is effective.

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 output schema exists (covering return values), the description covers the auth scope and provides a disclaimer. However, it lacks details on missing data behavior and does not distinguish from siblings, leaving some completeness gaps.

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 67%, and the description adds no extra parameter meaning beyond what the schema already provides. The schema handles parameter details adequately; description adds minimal value.

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 it gets SpO2 summary for a date, with a verb and resource. However, it does not differentiate from similar sibling day tools (e.g., fitbit_get_heart_day). The phrase 'when available' adds context but is insufficient to distinguish.

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 mentions a prerequisite ('Requires heartrate scope') and a disclaimer ('Not medical advice'), but provides no guidance on when to use this tool versus the many sibling get_*_day tools. No explicit when-to-use or exclusions.

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