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

With no annotations, the description carries the full burden of behavioral disclosure. It mentions being a 'Browser-based tool' and lists supported effects (shadows, outlines, gradients), but does not disclose input/output specifics, whether the original image is modified, or any limitations. This falls short of meaningful transparency for an agent.

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 a single concise sentence that front-loads the core functionality and immediately lists key features. Every part earns its place, with no unnecessary wording or repetition.

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?

While the description covers the main purpose and a few features, it lacks details about how the tool receives images, what output it produces, and any limitations. Given the absence of an output schema and annotations, this leaves noticeable gaps for an agent needing to know practical expectations.

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 tool has zero parameters, and the schema is empty with 100% coverage. Per the rubric, a baseline of 4 is appropriate since the description need not explain parameters. The description adds no parameter info, but none is needed given the input schema is empty.

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 overlays text on images and supports shadows, outlines, and gradients. It uses specific verbs ('重ねて配置') and resources ('画像'), making the primary function clear. However, it does not explicitly differentiate itself from sibling tools like watermark or telop-image-generator, which perform similar text-overlay tasks.

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?

No guidance is provided regarding when to use this tool versus alternatives such as watermark, telop-image-generator, or infographic-text-editor. The description lacks explicit context, exclusions, or alternative recommendations, leaving the agent to infer usage solely from the tool name and general description.

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