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

With no annotations and no output schema, the description carries the burden, but for a zero-parameter read-only enumeration the safety profile is inherently trivial. It does not disclose the return format (language codes vs display names), which is the one piece of behavior an agent would need.

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?

A single front-loaded sentence with no filler. Appropriately sized for a zero-argument tool.

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 trivial enumeration tool with no parameters, no annotations, and no output schema, the description is nearly complete. The only minor gap is the shape of the returned list, which matters little for a tool this simple.

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?

There are zero input parameters, so the baseline of 4 applies. No parameter meaning needs explaining, and the description correctly makes no claim about inputs.

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 (Returns) and resource (list of supported natural languages), which an agent can distinguish from the sibling detect_language or translate_text. It doesn't explicitly name a sibling to contrast with, so it stops 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?

No when-to-use context, prerequisites, or named alternatives. An agent can infer this is an enumeration helper, but the description gives no explicit guidance on when to prefer it over detect_language or the translate tools.

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