fitbit_get_spo2

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

With no annotations, the description fully carries the burden. It discloses caching behavior, sparse data condition (on-wrist sleep tracking), and premium requirement. No contradictions. Could mention rate limits, but overall thorough.

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?

Well-organized with clear sections. Front-loaded with main purpose. Not overly verbose, but could be slightly more concise without losing essential information.

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 complexity (3 params, no annotations, output schema present), the description covers: purpose, usage methods, prerequisites, limitations, parameter details, and return value shape. It is complete and informative.

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 0%, but the description explains all three parameters with formats, defaults, and behavior. start_date, end_date, and live are well-described, adding full meaning beyond the schema.

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 'Get nightly SpO2 data' with a specific resource and verb. It also mentions cache vs live data and a prerequisite, making the purpose distinct. However, it does not explicitly differentiate from sibling tools like fitbit_get_heart_rate, but the resource is unique enough.

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?

Provides explicit usage context: default cache vs live=True, prerequisite to run fitbit_sync, and requirement for Fitbit Premium. It lacks explicit when-not-to-use or alternative tools, but the context is clear.

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