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 burden of disclosing behavioral traits. It only states what the zones are and that they come from Garmin, without saying whether the call is read-only, what happens if no zones are configured, or whether any side effects exist. The agent must infer a harmless getter from the tool name.

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 exactly two sentences with no filler. The core resource definition is front-loaded, and the preference rule is a single concise sentence that earns 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?

For a zero-parameter lookup with an output schema, the description covers the source, the sport-specific scope, and the key usage rule. It is largely complete, though it could optionally note the possibility that the user has no Garmin-configured zones.

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 is empty and description coverage is trivially 100%, so there are no parameter semantics to clarify. This fits the 0-param baseline of 4.

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 identifies the resource as the user's Garmin-configured heart-rate zones and explicitly mentions sport-specific profiles, which distinguishes it from generic heart-rate or calculation-based tools. It lacks an explicit verb like 'retrieves', but the noun phrase plus the tool name makes the retrieval operation clear enough.

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 instruction 'Always prefer these over calculating zones from age or max HR' explicitly tells the agent to choose this tool whenever zone thresholds are needed rather than deriving them from formulas. It provides a clear exclusion but does not enumerate sibling-tool alternatives for other heart-rate data needs.

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