screenshot

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

With no annotations provided, the description carries the behavioral burden itself. It discloses that the tool returns a base64 PNG in envelope.image, lists named view directions, and notes that Fusion automatically performs fit-view for those directions. This is useful behavioral context, though it does not mention edge cases like whether the active view mutates or how transparent/anti-aliasing affect the output.

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 and front-loaded. The first sentence states the core behavior, the second clarifies the return value, and the third provides direction and fit-view behavior. Every sentence contributes value without fluff.

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 straightforward screenshot tool with no output schema, the description covers the essential return format and key camera behavior. It misses an explicit comparison with screenshot_compare_with_marker and the units/semantics of width/height, but the intent is still fully usable.

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. It only enriches the 'direction' parameter with a set of allowed values; width, height, transparent, and anti_aliasing are left with their schema defaults and titles only. This leaves the tool operating semantics relatable but insufficient.

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 starts with a specific verb and resource: 'Capture a PNG screenshot of the active viewport.' It clearly states the output format and image location. However, it does not explicitly distinguish itself from the sibling tool screenshot_compare_with_marker, so it misses the highest bar for sibling differentiation.

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 direction options and notes that Fusion handles fit-view internally, but it does not explain when to use this tool versus screenshot_compare_with_marker, set_view, or export. There is no explicit context for selecting this tool over alternatives.

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