garmin_hr_zones

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

No annotations are provided, so the description carries the full behavioral burden, yet it says nothing about read-only semantics, whether zones are Garmin defaults or user-customized, or whether the result is per-activity-type. 'Configured in your Garmin profile' gestures at static configuration but does not confirm it.

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?

A single short sentence with no filler, appropriately front-loaded. It loses a point only because the sentence fragment lacks a verb, making it read as a label rather than an instruction.

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?

The tool is simple (0 params, output schema present so return shape need not be explained), but with no annotations the description should still confirm the read-only nature and whether the zones are defaults or user-set. It is minimally adequate rather than fully complete.

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?

The input schema has zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. No misleading parameter hints are present.

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?

The description names a specific resource (heart rate zone definitions) and scopes it to the user's Garmin profile, which implicitly distinguishes it from garmin_heart_rate (measured data) and garmin_lactate_threshold. However, it is a bare noun phrase with no verb, and it never names the sibling it is not, so an agent must infer the read-fetch nature.

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?

There is no guidance on when to call this tool versus garmin_heart_rate, garmin_vo2max or garmin_lactate_threshold, and no stated prerequisites or coverage notes. The agent must derive usage entirely from the tool name and the presence of siblings.

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