Get daily summaries

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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds genuinely new behavior: payload size per day and the fact that ranges over a year are split into yearly requests, which matters for latency and result assembly. It does not say whether results are returned in order or what happens for days with no data.

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?

Two tight blocks: scope and cost/routing first, parameter contract second. Every clause earns its place — the metric list defines coverage, the size estimate justifies the sibling redirect, and the yearly-batching note explains latency.

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 2-parameter read-only fetch with no output schema, the agent knows what it gets (per-day grouped wellness metrics), how big it is, how to bound it, and when to route elsewhere. Annotations cover the safety profile, so nothing material is left unresolved.

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% — both parameters are bare nullable strings with no format hint — so the description carries the full burden and does it reasonably: YYYY-MM-DD format, inclusive bounds, and a documented default of the 7 days ending today. It does not state whether start must precede end or what happens with an inverted or malformed range.

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 and resource — daily wellness summaries grouped per day across a date range — and enumerates the ten included metric groups (movement, calories, heart rate, stress, body battery, etc.), which is far beyond a restatement of the name. It does not disambiguate itself from the near-identically named sibling garmin_get_daily_summary (singular) or garmin_get_day, leaving a real selection ambiguity.

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 an explicit when-not-to-use rule with named alternatives: for long single-metric trends, prefer garmin_get_steps, garmin_get_stress, or garmin_get_sleep_summaries, justified by the ~1-2 KB/day cost. It stops short of saying when this tool beats garmin_get_daily_summary or garmin_get_day, which are the closest competing options.

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