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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint, so the description's job is light. It adds useful behavioral context beyond the annotations by noting that Kelvin is also returned and by clarifying the direction values. There is no contradiction with 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?

The description is compact and front-loaded: the main action is stated first, followed by the Kelvin behavior, the direction instruction, and a source link. Every sentence contributes useful information and there is no redundancy.

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 simple read-only conversion tool, the annotations cover the safety profile, the schema fully documents both required parameters, and an output schema exists. The description adds the only missing detail—Kelvin is returned—so an agent has everything needed to call the tool correctly.

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?

The schema has 100% parameter description coverage, including enum values with a full explanation. The description merely restates the direction values ('c-to-f' or 'f-to-c') without adding new meaning about the value's range, format, or units, so it stays at the high-coverage baseline.

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 states a specific action—'Convert a temperature between Celsius and Fahrenheit'—and adds the extra Kelvin return, which clearly distinguishes it from generic temperature converters like hopi_oven_temperature_converter. It is not a tautology and fully explains the tool's primary function.

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 offers the 'how' by telling the agent to set direction to 'c-to-f' or 'f-to-c', but it does not specify when to prefer this tool over sibling converters or when not to use it. Usage context is only implied by the explicit units, not stated as a decision rule.

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