get_fitness_activities

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

No annotations are provided, so the description carries the full burden of revealing behavior. It adds a time-window hint but does not disclose whether results are daily aggregates, what 'up to end' means when end is null, or whether workout activities are excluded from 'fitness activities'.

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 a single concise sentence with no filler; the parentheticals and trailing 'up to end' add useful signal without bloat. Slightly terse, but every word 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?

The output schema covers return shape, so that is not a gap. However, with no annotations and many overlapping sibling tools, the description lacks usage-selection cues and sufficient parameter semantics to make fully informed invocation decisions. It is minimally adequate but incomplete.

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 0%, so the description must compensate. It relates 'days' to 'N' and 'end' to the endpoint, but does not explain accepted date formats, null semantics, the default behavior, or the parameter relationship, leaving key semantics under-specified.

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 states the resource ('fitness activities'), the specific data covered ('steps/calories'), and the time window ('last N days'), making the core purpose clear. It does not explicitly differentiate it from sibling tools like get_activities or get_daily_steps, but the parenthetical disambiguates the metric type.

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?

There is no guidance on when to use this tool versus alternatives, no exclusions, and no mention of how it differs from get_daily_steps, get_weekly_steps, or get_activities. Given the large sibling list, the agent is left to infer usage context.

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