get_daily_summary

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description goes beyond them with real interpretive caveats: fields appear only 'if present', Garmin's restingValue may fall back to absolute minimum HR, and stress/Body Battery keep Garmin's native scale. It doesn't say what happens when the 31-day cap is exceeded, but the domain caveats are genuinely useful.

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 tight sentences: what data first, then the range constraint, then data-quality caveats. Telegraphic style but every sentence carries distinct, non-redundant information.

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 an output schema present, return shape needn't be described, and annotations cover safety, so the description's job is range rules and field interpretation, which it does. The residual gap is sibling routing and the failure mode past 31 days.

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 coverage is 0%, so the description has to carry the load, and it does: ISO date format, inclusive bounds, the 31-day maximum, and end_date defaulting to start_date. Only start_date's role as the anchor of the range is left implicit.

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 names the exact data returned (daily steps, Garmin resting HR in bpm, stress, Body Battery), which distinguishes it from siblings like get_sleep and get_hrv without ambiguity. It omits an explicit verb such as 'returns' and doesn't state the grain (per-day records) outright, but the resource is unmistakable.

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 gives the operative constraint for calling it: an inclusive ISO range capped at 31 days, with end_date defaulting to start_date. It offers no guidance on when to prefer this over get_hrv, get_sleep, or list_activities, so the agent must infer the boundary from the field list alone.

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