waterMarkFont

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While it indicates the tool generates watermarked images (implying a write/mutation operation), it doesn't specify whether this modifies the original image, creates a new file, requires authentication, has rate limits, or what the output format/behavior is. For a tool with no annotations, this leaves significant gaps in understanding its effects.

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 extremely concise (one sentence: '生成带文字水印的图片') and front-loaded with the core purpose. There's no wasted language or unnecessary elaboration, making it efficient for quick understanding.

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?

Given the tool's complexity (image processing with mutation), lack of annotations, and no output schema, the description is insufficiently complete. It doesn't explain what happens to the original image, where the output is stored, error conditions, or any behavioral constraints. For a tool that likely modifies or creates files, more context is needed for safe and effective use.

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 schema description coverage is 100%, with both parameters ('objectKey' and 'text') clearly documented in the schema. The description adds no additional parameter semantics beyond what's in the schema (e.g., it doesn't explain how the watermark is applied, font/size options, or positioning). With high schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate but also doesn't detract.

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 '生成带文字水印的图片' (Generate images with text watermarks) clearly states the tool's purpose with a specific verb ('生成' - generate) and resource ('图片' - images). However, it doesn't distinguish this tool from potential sibling tools that might also manipulate images, though none of the listed siblings appear to be direct alternatives for watermarking.

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 provides no guidance on when to use this tool versus alternatives. There's no mention of prerequisites, limitations, or comparison with other tools in the server (like 'putObject' for uploading or 'imageInfo' for analysis). The agent must infer usage context solely from the tool name and description.

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