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

Annotations already declare readOnlyHint and openWorldHint, so the description only needs to add extra behavioral context. It adds the JPEG output format and the per-call cost of 5 points, which are useful operational details beyond the 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?

The description is compact, with a clear English sentence, a Korean equivalent, and the cost note. The bilingual repetition is somewhat redundant but serves accessibility and remains concise overall.

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 one-parameter, read-only tool, the description adequately covers input, output format, and cost. Missing details like viewport size or page-load behavior would be nice but are not essential for basic invocation.

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 input schema covers the only parameter fully with a description and example URL, so the tool description does not need to add parameter semantics. The description adds no new meaning about the url parameter beyond what the schema already provides.

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 clearly states the action (capture a screenshot), the resource (a web page URL), and the return type (JPEG image). This distinguishes it from sibling tools like url_html and url_similarity, which serve different purposes.

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 description implies the tool is for capturing visual screenshots, but it does not explicitly state when to choose it over alternatives such as url_html or url_similarity. There is no exclusionary guidance or mention of 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.