compare_reference_image

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

With no annotations, the description carries the burden of behavioral disclosure. It explains the capture-and-composite behavior and the aspect-ratio constraint, which adds useful context. But it does not disclose the output format, whether the operation mutates scene state, or what happens when the reference_name is missing.

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 compact and front-loaded with the core behavior, followed by a tight parameter list. Every sentence and bullet earns its place with no redundant content.

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 description covers the core invocation and the relationship to a stored reference, which is helpful. However, there is no output schema and the description does not state what the tool returns, what valid angle values are, or how failures are reported, leaving notable gaps for an agent relying solely on this description.

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 schema has 0% descriptive coverage, but the description explains all three parameters meaningfully: reference_name ties to store_reference_image, angle specifies the capture viewpoint, and max_size controls tile size. This fully compensates for the empty schema and gives an agent everything needed to fill the arguments correctly.

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 states a specific verb and resource: it captures the current viewport from a named angle and composites it with a previously stored reference image. This clearly differentiates it from generic capture tools and diff tools by describing the side-by-side composite output.

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 by referencing a name from store_reference_image and mentioning a previously stored reference, so an agent can infer the prerequisite. However, it does not explicitly state when to prefer this over sibling tools like diff_images or capture_viewport_angle, nor does it give exclusions.

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