capture_viewport

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

The readOnlyHint annotation establishes the tool is safe, and the description adds useful context: it writes a file and returns the file path. It does not mention overwrite behavior or error cases, but the added detail about return value goes beyond what annotations provide.

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, front-loaded sentence that states the action, target, and return value. Every word earns its place with no fluff or redundancy.

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 tool with one optional parameter and a clear return value, the description is largely complete. It could mention file format or overwrite behavior, but given the simplicity and presence of annotations, it is sufficient for most uses.

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 0%, and the description does not explain the 'filepath' parameter beyond implying it is the save destination. The parameter name and default value help, but the description adds no extra semantic detail, failing to compensate for low schema coverage.

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 uses a specific verb ('Capture') and resource ('3D viewport') and clearly states the output ('to a file. Returns the file path.'). This clearly distinguishes it from sibling tools like render_viewport or get_viewport_info.

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 when to use the tool (when you need a viewport screenshot saved to a file) but does not explicitly state alternatives or when not to use it. For a simple, self-explanatory tool this is acceptable but lacks explicit guidance.

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