Creates a fill layer in Substance Painter, optionally setting its sRGB base color and placing it above, below, or inside a reference layer.
Create a Fill Layer, optionally with sRGB base color [r,g,b].
position is top, or above, below or inside reference_uid.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | ||
| position | No | top | |
| base_color | No | ||
| texture_set | No | ||
| reference_uid | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It conveys that this is a creation/mutation and that placement can be relative to reference_uid, but it does not disclose whether a project must be open, what happens with an invalid reference_uid, whether the new layer becomes selected, or whether the operation is undoable.
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 the core action front-loaded and no filler. The position sentence is slightly awkwardly worded ('position is top, or above, below or inside reference_uid'), but it is compact and functional.
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?
An output schema exists, so return values need not be described, but for a five-parameter mutation tool with 0% schema coverage and no annotations, the description leaves texture_set and name unexplained and omits preconditions and side effects. It is under-specified for the tool's complexity.
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 0%, so the description must compensate for five parameters. It adds real meaning for base_color (sRGB [r,g,b]) and position (top/above/below/inside relative to reference_uid, which is not expressed in the schema), but name and texture_set receive no explanation at all.
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 ('Create a Fill Layer'), which distinguishes it from create_paint_layer, create_group, and insert_smart_material by resource type. It stops short of explicitly naming a sibling or contrasting use cases, so it is clear but not fully differentiated.
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 explains how to use two parameters but never says when to choose this tool over create_paint_layer or insert_smart_material, nor does it state prerequisites such as an open project or an existing reference layer. No when/when-not guidance is present.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.