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

Annotations already establish that this is read-only, idempotent, non-destructive, and closed-world. The description adds useful behavioral context by listing the computed outputs: effective ratio, before/after RPM, stock-feel restoration ratio, nearest sold gear set, and severity of the change. It does not contradict annotations, though it adds little about units, assumptions, or limits beyond the output 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?

The description is front-loaded with the intended use cases and then states what is returned. Every clause maps to a real query pattern, but the first sentence is long and lists several examples in a run-on way, making it slightly less crisp than 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?

With an output schema present, the description does not need to enumerate return values, but doing so reinforces what the tool computes. Annotations cover the safety profile, and the description covers the main use cases and the crawl-ratio dependency on first gear and transfer-case low ratio. It is complete enough to invoke correctly, though it could explicitly route overlapping tire-comparison questions elsewhere.

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 67%, and the description helps explain several parameters in context: old/new tires, axle ratio, highway speed for RPM, and crawl ratio using transfer-case low ratio plus first gear. It compensates for the two schema parameters with no descriptions by naming first_gear_ratio and transfer_case_low_ratio in the crawl-ratio use case. It still does not clarify tire notation or speed defaults, which the schema handles.

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 makes the tool's domain specific: gear ratio effects from tire changes, regearing, highway RPM, and crawl ratio. It gives concrete example queries and returned values, so an agent can tell it is not a bolt-pattern or wheel-fitment tool. It does not explicitly name or contrast with the closest sibling, tire_size_compare, so it falls short of a 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?

The description explicitly says to use this for "what does my 3.73 axle behave like on 35s", regear questions, highway RPM after tire changes, and crawl ratio calculations. That is clear positive guidance, but it does not state when not to use it or name an alternative tool for overlapping tire-comparison questions.

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