get_fitness

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

No annotations are provided, so the description should disclose behavioral traits like read-only nature, data source, or units. It merely lists output metrics without any behavioral context. There is no contradiction, but the description fails to carry the transparency burden.

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 a single concise phrase, listing three key metrics. It is front-loaded and contains no fluff. However, it's so brief that it verges on being a title rather than a descriptive sentence, so it doesn't earn a 5.

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), but the description could offer more context about what these metrics represent or how they're calculated. It's enough to know the tool returns fitness data, but it lacks clarity on scope or source. An output schema may fill the gap, but the description alone is minimal.

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, and the input schema is empty. Per the rubric, a baseline of 4 applies for 0 params. The description doesn't need to explain parameters, and it doesn't, which is acceptable.

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 identifies the tool's purpose: it provides VO2 max, cycling FTP, and race predictions. These specific metrics distinguish it from sibling tools like get_recovery or get_sleep. Though it's a noun phrase rather than a full sentence, the meaning is unambiguous.

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 use this tool versus alternatives. It doesn't state 'for fitness metrics' or recommend get_recovery for recovery data. The agent must infer usage solely from the listed metrics and sibling names.

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