garmin_hr_zones

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

Annotations already declare readOnlyHint and idempotentHint. The description adds substantial behavioral details: max HR derivation priority, use of Karvonen or %FCmax, e-bike caveat, and explicit statement that it does not write to Garmin. These go beyond annotations, though the description could mention that it may need recent activity data.

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 description is well-structured: purpose first, then algorithm, caveats, usage note, and finally args/returns. Every sentence provides useful information; no redundancy. Front-loaded with the core action.

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?

Given the complexity (multiple methods, fallbacks, caveats), the description covers all necessary aspects: algorithm, parameter roles, return format, and important notes (no writing to Garmin). Combined with rich schema descriptions and annotations, it is complete for correct invocation.

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?

Each parameter has a description in the input schema (e.g., age: 'Edad, para estimar FCmax...'). The tool description repeats some but also explains the overall algorithm, giving context (e.g., why max_hr is optional and how it influences the calculation). This adds value beyond the individual parameter descriptions.

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 clearly states 'Estima tus zonas de frecuencia cardiaca (Z1-Z5)', specifying the action (estimates) and resource (HR zones). It distinguishes from siblings like garmin_pace_zones (pace zones) and explicitly notes it does not write to Garmin, setting it apart from write tools.

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?

The description explains the algorithm and caveats (e.g., e-bike limitation) and notes the tool is read-only. However, it does not explicitly mention when to use this tool over other Garmin tools, though the context makes it clear this is the only HR zone estimator.

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