garmin_hr_zones

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine context beyond that: the values are in bpm and reflect the user's own Garmin settings rather than defaults, which matters for interpreting returned numbers. It says nothing about caching, latency, or what happens if zones are unset in Garmin.

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 short sentences, no filler, with the identity of the data front-loaded before the call-ordering instruction. Every sentence carries information the agent needs.

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 values need not be explained, and the description covers purpose and call sequencing for a simple one-parameter lookup. The remaining gap is the undocumented sport parameter, which is the only thing an agent could get wrong here.

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 description never mentions the sport parameter, so it adds no meaning beyond the enum values run/ride and the run default. It is left unclear whether zones differ per sport, which is the main semantic question an agent would have about this parameter.

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 — the user's own heart-rate zones in bpm, sourced from Garmin settings — which is unambiguous and clearly distinct from siblings like garmin_readiness or garmin_body_metrics. An agent knows exactly what data this returns 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?

Gives an explicit trigger condition: call it before garmin_workout_create whenever a workout is described by zone, naming the specific downstream sibling. It does not state any when-not-to-use conditions, but for a narrow read-only lookup tool that omission is minor.

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