get_viewport_screenshot

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

With no annotations provided, the description carries the full burden. It discloses the return type (Image) and explains the max_size and user_prompt parameters, but it does not explicitly state that the operation is non-destructive, require a running Blender instance, or describe any failure modes. This is moderate transparency.

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, starting with the main purpose, followed by a clear parameter list and return type. Every sentence adds value, and no unnecessary details are included.

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 screenshot tool, the description covers the essential aspects: what it does, parameters, and return type. It lacks explicit notes on prerequisites (e.g., Blender must be open) or potential errors, but given the simplicity, it is fairly 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?

The description provides meaningful explanations for both parameters: max_size is described as 'Maximum size in pixels' and user_prompt as 'original user prompt... for telemetry'. This goes beyond the schema's bare types and defaults. However, the stated default for max_size (800) conflicts with the schema's default (1000), which detracts slightly.

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 clearly states the tool's function with a specific verb ('Capture') and resource ('screenshot of the current Blender 3D viewport'). This distinguishes it from sibling tools like get_scene_info or execute_blender_code, which have different purposes.

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 purpose implies when to use it (when a viewport screenshot is needed), but there is no explicit guidance on when to use it vs alternatives like get_scene_info or execute_blender_code. No exclusions or alternative tool names are mentioned.

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