viewport_screenshot

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

With no annotations, the description carries the load and does disclose the critical side effect: the camera (and optionally visual style) is set and left there, so the user's view changes persistently. It also states the size bounds and the exact return payload. It omits whether/how the prior view can be restored, 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?

Front-loaded with the core purpose, then behavior, then bounds, then return shape, then an example — a sensible order. A mid-sentence line break and some redundancy ('and leaves it there') cost a point but nothing is wasted overall.

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?

No output schema exists, but the description names both return parts (image and JSON with width/height/orientation), and it flags the persistent camera mutation. An agent has enough to call it and interpret the result; only the restore/undo question is unaddressed.

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 60%; the description compensates for the undocumented width/height by stating the 64..2048 px range, and it explains that visual_style is optional ('and optionally the visual style'). The example shows orientation plus visual_style usage, adding meaning beyond the raw enum.

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?

States a specific verb and resource ('PNG picture of the active Fusion viewport') plus the intent ('to check the model visually'). No sibling tool offers viewport capture, so it is unambiguously distinct from export_cad/export_mesh.

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?

Gives clear context ('check the model visually') and an example invocation, which implies when to reach for it. It does not explicitly route away from alternatives such as export_cad or export_mesh, but the visual-inspection framing is strong enough for an agent to choose correctly.

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