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

There are no annotations, so the description carries the behavioral transparency burden. It discloses cost per use, positioning as 'cheap' and 'high-volume,' and the ISO-code output behavior, which goes beyond the bare schema. It could add a clearer read-only/no-side-effects statement, but the non-mutating verb and cost disclosure make intent reasonably transparent.

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 with the main purpose. The usage and pricing notes are useful, but the 'input=text' fragment is partly redundant with the schema, keeping this from being a perfect 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?

For a simple one-parameter, no-nested-object tool, the description is largely complete: it states the input, the purpose, the cost profile, and the output format. It does not specify the exact ISO format variant or how the result is wrapped, but this is a minor gap given the simplicity of the operation.

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 parameter is already documented and the description doesn't need to compensate heavily. The description adds the useful clue that 'input=text,' reinforcing that the single argument is plain text, but it doesn't add substantive detail such as encoding, length limits, or supported language coverage.

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 clearly identifies the tool as detecting the language of a text and specifies the output as an ISO code. This verb+resource pairing is specific and distinct from sibling translation tools, since it addresses detection rather than translation.

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 gives mild usage context by noting that the tool is 'cheap, high-volume for agents,' which implies it is suitable for bulk detection tasks. However, it does not explicitly state when to use it versus alternatives, nor does it name any excluded or preferred sibling tools.

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