Training readiness

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

Annotations already convey readOnly, idempotent, and non-destructive behavior, so the bar is lower. The description adds useful context: it is scoped to 'one day', includes a 0-100 score, and enumerates the underlying factors returned. No contradiction with annotations.

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, front-loaded with the core purpose, and wastes no words. The second sentence adds practical usage guidance and sibling differentiation without redundancy.

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?

With no output schema, the description adequately conveys what the tool returns: a score and the contributing factors. It also captures the tool's scope (single day) and purpose. Combined with the detailed schema and annotations, this is complete for a read-only retrieval tool.

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 provides full 100% coverage for both parameters, including relative date syntax and the summary/full distinction. The description does not add parameter-level detail beyond what the schema already documents, so the baseline score of 3 is appropriate.

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 the tool 'Get Garmin's training readiness score for one day (0-100)' and enumerates the factors it returns. It also explicitly distinguishes this tool from raw metrics by calling it 'Garmin's own synthesis of the recovery signals', setting it apart from likely sibling tools like sleep or HRV.

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 usage context: 'This is the tool for "should I train hard today"' and says it is a synthesis rather than a raw metric. It implies when not to use it (for raw metric inspection) but does not name specific sibling alternatives, so it falls just short of a 5.

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