assign_material

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

Annotations already establish this is a mutating, non-read-only operation. The description adds substantial context beyond that: duplicate=true creates a shared copy that can be edited without affecting the original, duplicate=false with a library material produces a solid red appearance in background rendering, and the operation is undoable via undo_material_changes.

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 front-loaded with the core action and then explains the duplicate behavior in a compact, structured way. It includes a useful version-specific caveat without excessive length.

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 output schema exists, the description does not need to explain return values. It covers the key behavioral risks of duplication and rendering, and the undo path, which is sufficient for an agent to call this mutation tool correctly.

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. It explains the duplicate parameter thoroughly and says material may come from the scene or library, but it does not clarify the format or identifier expected for material or the meaning of object_ids beyond 'pièces'.

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 states a specific verb and resource: 'Applique un matériau ... aux pièces object_ids', and clarifies the material can come from the scene or the library. It does not explicitly distinguish itself from sibling tools like set_material_parameter or add_material_node, so it falls just 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?

It gives clear guidance on when to use the duplicate option ('défaut, recommandé') and warns against applying library materials without a copy because they render red in background renders. It also points to undo_material_changes for reversal, but does not compare the tool against other material-editing siblings.

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