create_material_instance

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

The description discloses key behaviors: creation from a parent, error on existing asset, and destructive behavior of 'force'. With no annotations provided, the description carries the full burden and adequately informs about side effects. It does not mention permissions or additional requirements, but the core behavioral traits are covered.

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: two introductory sentences and a parameter list. Every sentence adds value without redundancy. The structure is front-loaded with the core purpose and error behavior, followed by clear parameter documentation.

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?

The description explains most parameters but omits the 'path' parameter (present in schema with default). While the output schema exists, the description could mention the return type. The missing path parameter is a notable gap for a 7-parameter tool.

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?

Despite 0% schema description coverage, the description fully compensates by listing each parameter with JSON examples and explanations. It clarifies what types to use for scalar_params, vector_params, and texture_params, and explains the effect of 'force'. This adds significant value beyond the raw schema.

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 explicitly states 'Create a Material Instance from a parent material,' which is a specific verb and resource. It clearly distinguishes itself from sibling tools like 'create_material' or 'build_material_graph' by focusing on instance creation.

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 provides clear guidance on error handling ('Returns error if asset already exists') and when to use the 'force' parameter to delete and recreate. However, it does not explicitly compare to alternative tools or specify prerequisites like required permissions.

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