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

The annotations already declare readOnly, idempotent, non-destructive, and open-world behavior, so the safety profile is covered. The description adds meaningful context beyond that: it states no authentication is required and enumerates the returned fields, which is exactly the extra information the annotations cannot supply.

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 core sentence is front-loaded and the bracketed [auth] and [output] tags are well-structured and scannable. The only waste is the verbatim Korean/English duplication of the same sentence, which adds length without adding 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?

For a simple, parameterless-in-practice metadata tool with no output schema, the description covers purpose, auth requirement, and the shape of the return value. The one genuine gap is the undocumented lang parameter, but otherwise an agent has enough to call this 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?

There is one optional parameter, lang, with 0% schema description coverage, and the description never mentions it at all — not what it controls, what values it accepts, or what happens when it is omitted. With a real parameter present, the zero-coverage baseline of 4 for parameterless tools does not apply.

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 verb and resource: it returns data freshness metadata — as-of date, coverage window, and sample size for the server's data. This is unmistakably different from the recommendation and surge siblings, though it never names or contrasts them explicitly.

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?

There is no explicit statement of when to call this tool versus alternatives, nor any precondition such as 'call before relying on recommendation results.' The usage is only implied by the metadata nature of the tool, so an agent must infer the trigger condition itself.

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