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

Annotations already establish the safe read-only, idempotent, closed-world profile, so the description's job is to add return-shape and limit context — which it does: issue positions, suggested correction, level semantics ("error" = certain vs "check" = review), a Korean-language reason, and the 10000-character per-call cap. Auth, rate limits, and handling of empty/oversized input remain unstated.

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?

Four compact sentences, front-loaded with purpose, then return shape, then caveats, then limits. Every sentence carries information an agent needs and none is redundant with the annotations.

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 3-parameter read-only checker with no output schema, the description adequately covers what comes back and the input cap. Slightly short of complete because error conditions (oversized text, non-Korean input) and rate/availability behavior are left unaddressed.

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 baseline is 3. The description reinforces the position-offset concept ("returns issues with positions") but does not explain the `apply` flag or the `offset_unit` choice, both of which are already fully documented in the schema.

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?

Names a specific verb and resource ("check Korean text for spelling and spacing errors"), names the underlying engine, and describes what the result contains. An agent knows exactly what the tool does and what domain it covers without opening the schema.

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?

Implies the usage context (Korean-language text, rule-based checker, 10000-character cap) and states exclusions in the form of "Proper nouns, quotes and style are not changed" — telling the agent what this tool will not fix. No alternatives exist to route against, so the absence of explicit when-to-use language is a minor gap.

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