Stress

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

Annotations already cover safety (readOnly, idempotent, non-destructive), so the description's added value is in return behavior: one row per day, overallStressLevel on Garmin's 0-100 scale, and the four duration fields measured in seconds. The 92-day cap and period-vs-date-range behavior are also disclosed. It stops short of describing ordering, empty-day handling, or missing-data behavior.

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?

Front-loaded with the core purpose and return shape, then alternatives, then constraints — a sensible ordering. The field enumeration is a long run-on clause, but each element (units, scale, cap) carries actionable information rather than filler.

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 read-only, three-parameter tool with no output schema, the description supplies the return shape, units, value scale, range limits, and sibling routing. An agent has everything needed to invoke it correctly on the first attempt.

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%, and the schema already documents the period enum semantics, the YYYY-MM-DD format, the default of end_date to start_date, and the 92-day max span. The description mostly restates this with example values and the period/start_date-end_date exclusivity, adding little meaning beyond the structured fields.

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?

States a specific resource and granularity: 'day-by-day all-day stress over a range, one row per day.' It enumerates the returned fields and explicitly differentiates itself from summarize_wellness (trends/weekday) and get_sleep_summaries (stress during sleep), so an agent can pick it without opening a schema.

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?

Gives explicit routing rules: use summarize_wellness for weeks/months or weekday analysis, and avg_stress in get_sleep_summaries for sleep stress. It also states the operational constraint (up to 92 days per call) and the two mutually exclusive ways to specify a range with concrete period examples.

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