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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description goes further by disclosing the 20 C fan offset rationale, the gas-mark table bounds, and that results are rounded to the nearest gas mark with an exactness flag. That rounding/exactness behaviour is real substance not present in the annotations.

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 sentences, front-loaded with the core conversion and followed by the return-value note; nothing is padded. The first sentence is dense with parentheticals, which costs a little readability but every clause carries information.

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 only three simple parameters, no output schema, and annotations covering safety, the description supplies everything an agent needs: input scales, gas-mark bounds, fan handling, and the shape of the returned gas mark plus exactness flag.

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 100% with enums for both fan and from_scale, so the schema carries the baseline. The description still adds meaning the schema lacks: the allowable gas-mark span (1/4 to 10) and the magnitude/source of the fan adjustment (20 C, manufacturer guidance), which tells an agent what the enum values actually do.

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?

A specific verb ('Converts') plus the exact resource ('an oven setting') and the three scales involved, including the gas-mark range 1/4 to 10. It also names the optional fan adjustment, so an agent can tell immediately this is a temperature-unit tool and not the ingredient converter among the siblings.

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 implies when it applies (converting an oven setting across F/C/gas, with or without fan adjustment) but never states explicit conditions, prerequisites, or when to prefer convert_ingredient instead. Usage is inferable from the title and description rather than spelled out.

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