get_viewport_screenshot_comparison

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

With no annotations provided, the description carries the behavioral disclosure burden. It clearly states that screenshots are captured from the user's current viewport and the active camera's perspective, and it documents the Base64 PNG return format. The read-only nature is strongly implied by the term 'screenshot,' though not explicitly stated.

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 well-structured: a one-line action, a one-line use case, and a short return-value list. Every sentence contributes useful information 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?

For a simple capture tool with two optional parameters and no output schema, the description covers the action, the two view sources, the use case, and the return encoding. It is slightly incomplete only in that it does not tie width/height to the screenshot resolution, but this is a minor gap.

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 should compensate by explaining the width and height parameters. It adds no param-level detail beyond what the schema already provides with names and defaults. The names are reasonably self-explanatory, but units and their effect on the screenshot are left unstated.

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 names a specific action ('Take two viewport screenshots') and identifies both resources: the user view and the active camera view. This clearly distinguishes it from the single-viewport sibling tool and leaves no ambiguity about what the tool does.

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 gives an explicit use case: 'Useful for verifying scene composition and camera framing.' This provides clear guidance on when to use it, though it does not explicitly mention alternatives like get_viewport_screenshot or render_preview or when not to use it.

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