compare_images

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

With no annotations, the description carries the full burden. It states that the tool produces a description of differences, similarities, or relationships, which conveys the core output behavior. However, it does not disclose potential limitations, failure modes, or the exact format of the output, leaving behavioral details ambiguous.

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, focused sentence that immediately states the action and resource. It avoids unnecessary detail and is well-structured, earning a high score.

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?

The tool is relatively simple, but with no output schema, the description should clarify the return structure. It states the tool will 'describe' differences, but not whether the output is a single combined summary or per-pair comparisons. This ambiguity makes the description only minimally complete.

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?

Both parameters are fully described in the schema (100% coverage), so the baseline is 3. The description doesn't add further semantic meaning beyond the schema, though it does reinforce the 'two or more images' constraint. No additional parameter context is 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's function—comparing multiple images and describing their differences, similarities, or relationships—and distinguishes it from siblings like analyze_image and describe_scene, which focus on single images. The verb 'compare' and the explicit 'two or more images' scope make the purpose unambiguous.

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 mention when to prefer this tool over siblings such as analyze_image or describe_scene. There are no explicit alternatives or exclusions, so guidance is only implicit through the requirement of at least two images.

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