Get wellness activities

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds value by describing the return record shape (per-metric summary values, time in zones) and the default date window, but says nothing about result volume, pagination, or behavior for devices with no wellness activities — which matters for an open-world read tool.

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 return-value description is front-loaded and the sibling exclusion follows immediately, which is the right ordering. Slightly wasteful: the trailing parameter note sits after a line break in a separate block rather than being integrated, and 'Regular workouts like runs and rides are in...' is a bit wordy.

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 no output schema, the description correctly compensates by summarizing the returned fields, and it covers both optional parameters and the sibling boundary. Complete enough to call correctly; only edge-case behavior (empty results, date range limits) is absent, which is minor for a read-only lookup.

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 carries the full burden and mostly delivers: 'start, end: YYYY-MM-DD inclusive (default: the 7 days ending today)' supplies format, inclusivity, and default semantics that the bare anyOf string schema lacks. Only the timezone basis for 'today' and invalid-format handling are unstated.

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 ('Wellness activities recorded by the device') and enumerates what each record contains: type, start/end time, per-metric summaries, time in zones. It also names the sibling that handles the confusable case (runs/rides -> garmin_search_activities), so an agent can disambiguate without opening the 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?

Explicitly routes regular workouts to garmin_search_activities, which is the main selection ambiguity. However, it gives no guidance on when to prefer this over the many daily-summary siblings (garmin_get_day, garmin_get_daily_summary, etc.), so a portion of the routing decision is left implicit.

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