garmin_athlete

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe read operation. The description adds behavioral context by noting the data 'changes rarely' and suggesting a single call, which informs the agent about stability and call frequency. It does not contradict annotations, and the added context goes beyond what the structured fields provide.

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 two sentences with no redundant words. The first sentence lists the data categories in a compact, scannable format. The second sentence delivers usage guidance and the sibling reference. Every clause contributes meaning.

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 that the tool has an output schema (which handles return details), no parameters, and annotations covering safety, the description fully covers the essential context: what the tool provides, when to call it, and how to update the underlying data. The presence of sibling tools like 'garmin_reference' and 'garmin_set_profile' makes the explicit differentiation valuable and 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 tool has zero parameters, so the schema contains no information to clarify. The description's content list serves as the semantic context for what the tool returns, effectively compensating for the lack of parameters. With no params, the baseline is 4, and the description meets that baseline by conveying the scope of the reference card.

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 uses 'Reference card' followed by a concrete list of contents (zones, thresholds, PRs, goal and phase, baselines, injury notes, device data coverage), making the tool's purpose immediately clear. It also distinguishes itself from the sibling 'garmin_set_profile' by explicitly stating that changing the profile is a different tool's job.

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 gives explicit when-to-use guidance: 'Call once when athlete context is unknown; it changes rarely.' It also provides an alternative: 'To change it, garmin_set_profile.' This clearly tells the agent when to invoke this tool and when to use a sibling instead.

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