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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds that the result is VMA in km/h plus zones, but that overlaps the output schema and says nothing about auth, rate limits or edge-case behavior.

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?

Short, front-loaded and free of filler, with the purpose stated first and inputs/returns after. The trailing 'See list_bundles' sentence is mildly tangential but still a useful pointer, so it does not seriously hurt the score.

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 an output schema, full schema descriptions and rich annotations, the description only needs to establish purpose and scope, which it does. A note on which test type to pick or how VMA relates to the sibling VO2max tool would make it fully self-sufficient.

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?

Schema description coverage is 100%, so the baseline is 3 and the schema already documents both parameters fully. The description's inline restatement is actually less complete and slightly off (it lists only two test types and says 'Luc Léger' where the enum is cooper/demi_cooper/vameval), adding no real meaning beyond the schema.

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?

States a specific verb and resource ('Compute VMA ... from a fitness test result') and expands the acronym, so an agent knows exactly what is produced. It does not explicitly differentiate itself from near siblings such as calculate_vo2max or calculate_training_zones_running, which is the only thing keeping it out of 5.

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?

'Use for runners building training plans' gives a target audience but no when-not guidance and no named alternative for the same job. The pointer to list_bundles is a cross-reference to related calculators, not a routing rule between competing tools, so usage is only implied.

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