Get Daily Strain Cycles

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context: the physiological-day definition, the 0-21 strain scale interpretation, and the expected return fields. This goes beyond the annotations to help the agent understand data semantics, though it omits details like pagination 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?

The description is well-structured with a concise main statement, a clarifying definition, a strain scale breakdown, and bullet lists for parameters and return fields. It contains substantial useful detail without fluff, though it is longer than minimal; the organized sections earn their place for readability.

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?

With no output schema, the description fully compensates by explicitly listing return fields (strain, kilojoule, average/max_heart_rate). It also covers the conceptual cycle definition, parameter ranges, and the strain scale, making it self-contained for a read-only tool with strong annotations. This is a complete, well-rounded description.

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 100% for all three parameters (limit, start, end). The description essentially repeats the same parameter semantics (limit 1-25 default 7; ISO 8601 filters) without adding new meaning beyond the schema. It does list return fields, which indirectly clarifies parameter effects, but the baseline of 3 applies.

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 a specific verb ('Retrieves') and names the resource ('physiological cycle (day) data' including daily strain, calories, and heart rate). It clearly distinguishes from sibling tools by focusing on daily cycles and strain, and explicitly clarifies that a cycle is wake-to-wake, not a calendar day.

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 implies usage for daily strain and cycle data with detailed semantics (cycle definition, strain scale), but it does not explicitly mention when to use this tool versus siblings like whoop_get_recovery or whoop_get_sleep. There are no exclusions or alternative tool references, leaving usage guidance only implicit.

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