blender_paint_vertex_colors

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

Annotations already mark the tool as non-read-only and non-destructive, and the description adds the core behavior of writing a per-vertex gradient. It does not disclose side effects such as whether an existing vertex colour layer is overwritten or created if missing, but the annotation coverage lowers the burden.

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?

Two short sentences with no filler. The action is front-loaded, and the use cases follow efficiently.

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 6-parameter mutation tool with no output schema, the description covers purpose and use cases but omits behavior around existing layers and response details. Schema descriptions fill most parameter gaps, making it adequate but not fully 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 83%, so the baseline is 3. The description adds no parameter-specific detail beyond what the schema already provides for axis, layer, color_a, color_b, and response_format.

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 ('Write per-vertex colours as a gradient along an axis') and resource (vertex colours), which clearly distinguishes it from texture painting or other painting tools. However, it does not explicitly name or differentiate from a sibling alternative, so it stops short of a 5.

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 phrase 'Useful as a mask, for toon shading, or for baking masks into a vertex colour layer' gives concrete use cases and implies when to use the tool. It does not explicitly contrast with alternatives like blender_paint_texture or state when not to use it.

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