health_get_hrv

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently reveals that data comes from a local cache by default, that live=True bypasses the cache, and that running health_sync is needed to populate it. This is exemplary transparency for a health data tool.

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 yet complete, using a clear structure: a one-sentence purpose, cache behavior, a sync prerequisite, a caveat about sparse data, parameter definitions, and return value explanation. Every sentence adds value without redundancy.

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 and no annotations, the description provides a complete picture: what data is returned (one entry per night with daily_rmssd and deep_rmssd in ms), the relationship to sleep tracking, and the cache behavior. It addresses the complexity of the domain by explaining RMSSD meaning, making it fully self-contained.

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?

All three parameters (start_date, end_date, live) are fully documented with formats and semantics. The description explains date formats ('YYYY-MM-DD', 'YYYY-MM', or '30d'), defaults, and the meaning of live, which the input schema itself does not provide (only types and defaults). This goes well 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 the tool's purpose: 'Get nightly HRV (heart rate variability) data.' It specifies the resource (HRV) and the verb (get), and distinguishes it from siblings like health_get_heart_rate. The mention of 'nightly' and cache behavior adds precision.

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 instructs to 'Run health_sync first to populate the cache,' which is a clear prerequisite. It also notes that HRV data is sparse ('only nights with on-wrist sleep tracking produce readings'), guiding the agent on when to expect missing data. The live=True option is explained for forcing API fetch, giving concrete context for when to use it.

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