WHOOP Recovery Trend

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

Annotations already convey readOnly, non-destructive, and idempotent behavior. The description goes further by stating it 'fetches recent WHOOP v2 records, computes statistics, stores nothing,' and it explains the slope calculation and direction value semantics, providing concrete computational behavior beyond the annotation hints.

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 purpose is front-loaded, and each of the four sentences adds meaningful detail about output fields, use case, or safety. The 'Not medical advice' clause is slightly extraneous but does not significantly hamper clarity.

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?

For a statistical aggregation tool, the description defines every returned field (avg, min, max, slope, direction, n_valid) and explains direction values. It does not explain how response_format changes the returned structure, but the presence of an output schema likely covers that; the overall description is nearly complete for tool selection and invocation.

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?

The schema already describes days and timezone, and the description only repeats the default of 30 for days. The response_format parameter lacks any description in both the schema and the tool description, leaving the agent uninformed about when to choose 'markdown' vs 'json.' With 67% schema coverage, the description does not compensate for this gap.

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 opens with 'Aggregate WHOOP recovery over the last N days into a per-metric trend for recovery score, HRV and resting heart rate,' specifying a clear verb, resource, and scope. It also distinguishes itself from raw-list siblings by saying 'without paging the raw collection yourself,' making its role explicit.

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?

It provides an explicit use case: 'Use this to answer "is my recovery trending up or down?"' and contrasts with paging raw collection, thereby implying an alternative. However, it does not name a specific sibling tool, so the differentiation is slightly less direct than it could be.

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