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

Annotations provide readOnlyHint=true, and the description adds that it returns a new PDF ('PDF 를 반환합니다'), supports adjustable attributes (size, color, opacity, angle, density, area), restricts input to PDFs, and costs 10 points per call. These details are consistent with the annotations and provide additional behavioral context.

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 short and front-loaded with the primary action. However, the English and Korean sentences are redundant (both state watermarking across every page of a PDF). The additional cost note is useful, but the duplication slightly detracts from conciseness.

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 9-parameter tool with no output schema, the description covers the core behavior, return type (PDF), input restriction, adjustability, and cost. It does not elaborate on error cases or authentication, but the schema and annotations fill most gaps, making it complete enough for a PDF watermarking tool.

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 descriptions cover all 9 parameters with ranges and defaults, so the baseline is 3. The description mentions adjustable attributes (글자 크기·색상·투명도·각도·밀집도·적용 영역) but does not add any syntax or format details 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 tool draws a visible text watermark across every page of a PDF file and returns the modified PDF. The action (draw) and resource (PDF) are specific, and the mention that only PDF format is allowed distinguishes it from image watermarking tools.

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 gives clear context: it is for PDF files, and explicitly states that only PDF format is allowed ('PDF 형식의 파일만 허용됩니다'). However, it does not mention alternative tools (e.g., draw_watermark_image) for non-PDF inputs, so explicit when-not/alternative guidance is absent.

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