set_material_instance_scalar

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

With no annotations, the description carries the full burden of behavioral disclosure. It only restates the action and provides no information about side effects, persistence, or prerequisites (e.g., whether the material instance must be loaded or whether the parameter must already exist). It adds no transparency beyond the schema description.

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 a single, front-loaded sentence with no wasted words. It directly states the operation and is immediately scannable.

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 tool is a simple setter, but with no annotations or output schema, the description should provide more context (e.g., whether it modifies the asset, persists, or requires a loaded material instance). The schema covers parameters, but the description alone is thin for guiding an agent safely, so it is minimally 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 100%, with each parameter having a clear description ('Material instance asset path', 'Scalar parameter name', 'Parameter value'). The tool description adds no extra meaning beyond the schema, so the baseline score of 3 is appropriate.

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 action: 'Set a scalar parameter on a material instance.' It uses a specific verb ('set') and a specific resource ('material instance') with a specific parameter type ('scalar'), which distinguishes it from sibling tools like set_material_instance_vector and set_material_instance_texture.

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 implies usage (when you need to set a scalar parameter), but it does not explicitly state when to use this tool versus alternatives or mention any exclusions. Sibling tool names provide implicit context, but explicit guidance is absent.

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