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

No annotations are provided, so the description carries the full burden. It implicitly communicates that this is a pure, deterministic conversion with no side effects, but says nothing about rounding/precision of results or error behavior on non-positive or non-finite input (the schema hints at this constraint but the description does not). Low-stakes behavior, so a 3 rather than lower.

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?

One sentence, zero filler, with the conversion scope front-loaded. Nothing is repeated or 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 a full output schema and 100% schema coverage, the return shape and parameters are covered elsewhere, so the description only needs to establish purpose and unit scope, which it does. The remaining gap is the absence of any precision/rounding note for the converted values.

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 every parameter, including that 'to' is optional and defaults to returning all units. The description's unit list duplicates the enum values and adds no syntax or format detail beyond the schema; baseline 3 applies.

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 ('Convert') and resource ('fuel economy value') and enumerates the four supported units, which cleanly separates it from the sibling converters (convert_distance, convert_power, convert_speed, etc.). An agent can route to it without opening the schema.

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?

Usage is implied by the unit list, but there is no explicit when-to-use guidance, no mention of how it differs from calculate_fuel_cost, and no stated prerequisites or exclusions. Adequate for a straightforward converter but not instructive.

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