blender_render_before_after

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

Annotations already indicate destructiveHint=true, so the agent knows it's a mutation tool. The description adds meaningful behavior beyond annotations by stating that the tool executes bpy code between captures and returns a side-by-side comparison. This clarifies the mechanics and side effects of running arbitrary code, which is valuable context. It doesn't contradict annotations.

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 extremely concise: two sentences that front-load the purpose, explain usage, and state the return value. Every sentence earns its place with no redundancy or 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?

Given the tool's complexity (executing user code and capturing before/after screenshots) and the lack of an output schema, the description is reasonably complete: it states what it does, what to provide, and what it returns. It could mention the current scene context or potential side effects of code failure, but the essential information is present.

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 schema has only one parameter 'code' with no description (coverage 0%). The description compensates by explaining the purpose: 'Provide the bpy code to execute between captures.' This gives meaning to the parameter, though it could be more specific about the expected format or scope (e.g., that it's Python/Blender code). Still, it adds sufficient clarity for a single simple parameter.

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: 'Capture before/after screenshots around a modeling operation.' This uses a specific verb ('capture') and resource ('before/after screenshots'), and distinguishes it from sibling tools like blender_get_screenshot or blender_render_tiled by emphasizing the before/after comparison aspect.

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 clear context for use: 'around a modeling operation' and instructs to 'Provide the bpy code to execute between captures.' This implies when to use it, though it doesn't explicitly name alternatives or exclusions. It's clear that this tool is for capturing a side-by-side comparison before and after a user's custom code execution.

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