Health vitals

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

Annotations already indicate readOnlyHint=true, so the description adds value by noting that sections the ring does not measure return empty, and that data defaults to the last 7 days. This provides behavioral context beyond the annotation.

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 sentences with no extraneous words. Every sentence provides essential information: what the tool returns, its use case, handling of missing data, and default range.

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 no output schema, the description lists the key return fields (SpO2, resilience, etc.) and mentions empty sections. It covers the tool's scope adequately, though a brief note on response format would be nice.

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 coverage is 100% (both parameters described with dates and defaults). The description adds that it defaults to 'last 7 days', which supplements the schema's default values and clarifies behavior.

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 retrieves 'slow-moving health metrics' like SpO2, resilience, cardiovascular age, VO2 max. It distinguishes from siblings by specifying these exact metrics, which are absent in other Oura tools.

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 says 'Use for what is my SpO2 / vascular age / VO2 max / resilience', which tells the agent when to invoke this tool. While it does not provide explicit when-not scenarios, it implies that other tools (e.g., oura_get_heartrate) are for different metrics.

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