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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds only the fixed size of the list (29 codes), which is minor context; it does not describe return shape or ordering, though a static enumeration needs little more.

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?

Front-loaded single English sentence that carries the key fact, followed by a short Korean gloss. The bilingual restatement is mildly redundant but compact and does not obscure the primary content.

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 zero-parameter, read-only enumeration with no output schema, the description supplies exactly what an agent needs: what is listed and who consumes it. Nothing further is required to call it 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 tool takes no parameters, so the baseline is 4 per the rubric. Nothing in the description needs to compensate for a schema, and it correctly implies a parameterless enumeration.

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 (List) and resource (29 language/variant codes) and explicitly ties them to the two sibling tools that consume them. An agent can immediately distinguish this from to_hangul and lookup_ipa.

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?

By naming to_hangul and lookup_ipa as the consumers, it makes the use case clear: call this to discover valid language codes before invoking those tools. No explicit when-not or negative guidance, but the routing context is strong.

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