get_training_zones

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds value beyond that: it explains what each zone object contains (name, bounds, absolute range) and how values are derived (% of FTP, bpm, % of threshold speed), and notes the 'current settings only' constraint. No auth/rate-limit detail, but that is minor given the annotation coverage.

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?

Front-loaded with purpose, then return-content detail, then the 'current settings only' constraint, then the alternative tool pointer. Dense but nearly every clause earns its place; the 'read-only' note is the one duplicated element since the annotation already states it.

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 carries the burden of explaining returns and does so (zone name, bounds, absolute range, and the unit basis of each zone type). Combined with the alternative-tool pointer and the caching/refresh context in the schema, an agent has everything needed to call it correctly.

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 100%, so the schema already documents all five parameters including the zone_type and output_format enums. The description adds contextual framing ('each sport setting', 'current settings only') that maps loosely onto sport_type and refresh, but no syntax or format detail beyond the schema. Baseline 3 is appropriate.

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+resource ('training zones') and enumerates the three zone types (power, HR, pace) across sport settings. It names the sibling get_sport_settings for the adjacent-but-different content (thresholds), so an agent can distinguish it without opening a 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?

'Use for...' plus 'Current settings only' and 'Thresholds and other settings: get_sport_settings' gives clear usage context and explicitly routes one alternative. It stops short of exclusions against the curve siblings (get_athlete_power_curves, get_hr_curves), leaving a small inference gap, but the when-to-use is well stated.

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