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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds the return shape {power_watts, watts_per_kg} and the notion of 'total mass', but says nothing about the underlying model — whether wind, rolling resistance, or drivetrain losses are assumed, which materially affects trusting the output.

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?

Two short sentences, front-loaded with the purpose; nothing is padded. The return-value sentence is slightly redundant given an output schema exists, but it is brief and not harmful.

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 small pure-calculation tool with 100% schema coverage and an output schema, the description covers purpose, inputs, and return fields adequately. The main remaining gap is the physical assumptions behind the estimate, which an agent might reasonably want before presenting results as authoritative.

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 schema already documents all four parameters, making 3 the baseline. The phrase 'total mass' is a mild value-add because it hints that weight_kg and bike_weight_kg are combined, but no formula, unit convention, or gradient sign behavior is added 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?

The description gives a specific verb ('Estimate'), a specific resource ('cycling power output'), and the driving inputs (gradient, speed, total mass). This clearly separates it from confusingly named siblings like calculate_electrical_power or calculate_power_unit_convert. It does not, however, explicitly name a sibling it supersedes or differs from.

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 when-to-use, when-not-to-use, or alternative-selection guidance. The only navigation hint is 'See list_bundles for related sport calculators,' which is a discovery pointer rather than a condition for choosing this tool over e.g. calculate_velo_development or calculate_braquet.

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