Wellness activity summaries

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's job is to add operational context — and it does: 'Often empty' sets return-volume expectations, 'returned as Garmin sends them' discloses raw passthrough with no normalization, and the 92-day cap constrains request size. It stops short of describing result shape or ordering.

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?

Three sentences, zero filler, and the highest-value facts come first: what it is, how it differs from workouts, then the emptiness caveat and alternatives, then the range constraint. Every clause earns its place.

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?

No output schema exists, so the description carries the return-value burden; 'returned as Garmin sends them' plus 'Often empty' is a reasonable disclosure for a passthrough read tool, and the sibling routing covers the main decision. A brief note on what a non-empty record contains would close the remaining gap.

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 enum values, the YYYY-MM-DD pattern, inclusive semantics, and the 92-day max span. The description's 'Up to 92 days per call: pass a period ... or start_date/end_date' restates the mutual exclusivity the schema already implies. Baseline 3 for a fully documented schema with no added format or precedence detail.

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 verb+resource (wellness activity summaries over a range) and immediately scopes it: 'all-day movement records kept apart from recorded workouts.' That contrast is exactly what an agent needs to distinguish this from the workout-oriented siblings, and it is reinforced by naming those siblings later.

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?

Explicit routing in both directions: 'for daily movement use get_daily_summaries or get_steps, and for workouts search_activities or summarize_activities.' It also warns 'Often empty,' which is real selection guidance (an agent should prefer alternatives when it needs reliable daily data).

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