compare_images

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

No annotations are provided, so the description carries full burden. It mentions return values ('differences with severity and confidence') but does not disclose safety, authorization requirements, or side effects. It is acceptable but lacks depth.

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?

Two tightly written sentences: first states purpose, second lists use cases and return values. No fluff, front-loaded with key action, and every part adds value.

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 7 parameters, no required fields, no annotations, and an output schema, the description is adequate for basic understanding but lacks detail on parameter semantics and behavioral context (e.g., security, restrictions). More guidance would improve completeness.

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 description coverage is 0%, so the description must compensate. However, it only vaguely references parameters through use case examples (layout, text, color) and does not explain the focus enum, paths, or severity_threshold. Most parameters remain undocumented.

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 verb 'compare' and resource 'two images', and lists specific use cases (before/after screenshots, visual regression, etc.), distinguishing it from sibling tools like analyze_image or extract_region.

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 says 'Use this for...' followed by a comprehensive list of scenarios (UI changes, layout shifts, etc.), providing clear context for when to use. It does not include exclusions or alternatives but is sufficient.

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