ui_diff_check

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals the core behavior (comparing images, identifying differences, producing a report) but does not mention side effects, permissions, supported formats, or limitations. Since the tool is inherently read-only, the lack of side-effect disclosure is a minor gap but not misleading.

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 concise and well-structured: the purpose is front-loaded in the first sentence, followed by a clear bulleted list of use cases and a final note about required inputs. Every sentence earns its place, with no redundancy or filler.

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?

There is no output schema or annotations, so the description should clarify the return value. It mentions a 'detailed diff report' with severity prioritization but does not specify the report format or any limitations (e.g., image formats, size limits). Given the tool's relative simplicity, this is adequate but not fully comprehensive.

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 coverage is 100%, so the baseline is 3. The description only restates that two images are required (expected vs. actual), which duplicates the schema parameter descriptions. It adds no extra meaning for the 'prompt' parameter beyond what's already provided.

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 compares two UI screenshots to identify visual differences and implementation deviations, and positions it specifically for UI QA and design-to-implementation verification. This distinguishes it from sibling tools like analyze_image or extract_text_from_screenshot, which have 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 explicitly lists when to use the tool ('仅在用户需要以下操作时使用') with four concrete use cases, providing clear context. However, it does not name alternative tools or explicitly state when not to use it, so it stops short of full when-not/alternatives guidance.

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