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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description adds the non-obvious cost of 20 points per call and the fact that capture is full-page. It does not describe the return structure (image format, block schema), which matters somewhat since there is no output schema.

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 and short, but the English first sentence and the Korean second sentence convey identical information, so roughly half the text is duplication. The use-case and cost sentences do earn their place.

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 single-parameter tool with annotations covering safety, the description covers what is captured, what is returned at a high level, and the cost. Only the shape of the returned text blocks and image format are left unstated, which is a minor gap given no output schema exists.

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?

Only one parameter (url) and schema coverage is 100%, with the schema itself noting http/https. The description adds nothing to parameter meaning beyond what the schema already states, so the high-coverage baseline of 3 applies.

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 compound action: capture a full-page screenshot AND return on-screen text blocks with x/y/width/height coordinates. This is more specific than the sibling url_screenshot or url_html, but the description never names those siblings explicitly, so the differentiation must be inferred.

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 Korean sentence '이미지 위에 글자 위치를 표시하거나 화면 구성을 분석할 때 사용합니다' gives a clear use context: overlay text positions on an image or analyze screen composition. It stops short of naming alternatives (url_screenshot, url_to_markdown) or stating when not to use it.

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