compare_images

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

With no annotations, the description carries full burden, but it only adds that it 'supports local file paths and URLs.' It does not disclose limitations (e.g., file size, format support) or what happens if images fail to load, leaving behavioral gaps.

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 (single sentence) and front-loaded with the main action. It could include a brief usage example but is efficient overall.

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 no output schema and two simple params, the description lacks guidance on return format, error handling, or comparison depth. More completeness would aid agent invocation, especially with three sibling tools.

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%, and the description adds value by clarifying that images can be file paths or URLs (beyond schema's 'file paths or URLs'). The prompt parameter's description matches the schema, providing adequate context.

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's purpose: 'Compare 2-4 images and describe differences/similarities.' It specifies the verb (compare), resource (images), and acceptable input types (file paths or URLs), distinguishing it from siblings like analyze_image and ocr_image.

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 implies usage for comparing multiple images but does not explicitly state when to use it versus alternatives like analyze_image. No guidance on when not to use or prerequisites is provided, which is a moderate gap.

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