ap_capture_viewport

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

With no annotations provided, the description carries the transparency burden, and it does well: it discloses the dependency on the viewport patch, the unsupported-code failure mode, and the fallback behavior. It stops short of specifying other side effects such as overwrite semantics or exact response shape on success, which keeps it from a 5.

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 front-loaded with the primary purpose and then adds a single, dense caveat paragraph covering compatibility and fallbacks. Every sentence contributes information an agent needs; there's no fluff or repetition.

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?

Given there is no output schema, the description usefully explains that success returns an image and that include_image=false returns just the path, and it covers the unsupported-build case. It does not describe the broader response envelope, but for a capture-and-return-image tool this is reasonably 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?

Schema description coverage is 100%, so the schema already documents all four parameters including defaults and the include_image behavior. The description adds no additional parameter-level meaning beyond confirming the output is a PNG image, which matches the baseline for full 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 names a specific operation ('Capture the shaded 3D viewport to a PNG file') and clarifies the return value ('return the image so you can look at your own work'). It also differentiates the tool from nearby siblings by naming the fallbacks and their limitations.

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 explicitly states the prerequisite (optional viewport patch) and what happens on a stock build ('unsupported'), then names the two fallback alternatives with the precise conditions for each (in-project only vs real flat files). This gives an agent clear routing guidance.

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