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

Beyond the annotations (readOnly, non-destructive, closed-world), the description discloses meaningful modeling assumptions: per-lap consumption applies to race, formation, and allowance laps, and finish weight retains only the selected reserve. These are non-obvious behavioral traits not derivable from the schema.

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?

It is front-loaded with the outcome and then layered with assumptions and cautions; every sentence serves a purpose. The five-sentence block is dense but not padded.

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 present and full schema coverage, the description needn't explain return values, and it correctly focuses on assumptions and validation caveats for this 14-parameter calculator. Slightly more explicit guidance on raceMode/duration vs raceLaps usage would make it fully 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?

Schema coverage is already 100%, so the baseline is 3, but the description adds real semantics: how 'consumption' is propagated across lap types and what 'reserve' does to finish weight. That meaningfully supplements the parameter definitions.

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 opens with a specific verb ('Plan') and concrete resources: race fuel load, reserve, start weight, and minimum-weight margin. This clearly distinguishes it from siblings like calculate_ethanol_blend or calculate_fuel_injector_size, which compute different quantities.

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?

It implies the planning context and adds the caution to 'confirm your series weighing rules and validate consumption with real data,' which hints at when the result is trustworthy. However, it never states when to prefer this over the other fuel-related calculation siblings, leaving alternatives to inference.

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