get_activity_power_in_timezones

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

The annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so 'Garmin Connect, read-only' merely restates them. Beyond that, the description discloses nothing about how zones are derived (user-configured vs. defaults), what units the time is in, or whether the activity must have power data; the date-format note is a non-sequitur.

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 first sentence is well front-loaded and does the real work. The parenthetical second sentence spends words on a date-format rule that cannot apply to this tool's inputs, so it does not earn 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?

An output schema exists, so return-value detail is not required. Still missing is the context an agent needs to call this correctly: the origin of activity_id and any prerequisite that the activity contain power-meter data; the spurious date note partly crowds out that information.

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% and the single parameter, activity_id, is never explained. The description should say where an activity_id comes from (for example, get_activities) and that it accepts an integer or string, but it instead talks about date formats that no parameter uses.

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: return time spent in each power zone for an activity. This implicitly distinguishes it from the sibling get_activity_hr_in_timezones (heart-rate zones vs. power zones), though it never names that sibling explicitly.

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?

No guidance on when to use this instead of get_activity_hr_in_timezones, get_activity_details, or get_activity_splits, all of which could look plausible for a similar question. The only contextual note, 'Dates are YYYY-MM-DD,' is irrelevant because the schema has no date parameter, which adds confusion rather than guidance.

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