create_physical_material

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

Goes beyond the annotations by spelling out the idempotent semantics concretely: existing assets are loaded, provided values re-applied, and a stable payload returned. This is meaningful context on what happens on the exists-path that the idempotentHint flag alone does not convey, though it doesn't state what happens to fields left unset.

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 front-loaded sentences: the create action first, then the idempotency contract. The inline Returns block is compact and every clause carries information an agent needs.

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?

With no output schema, the description carries the burden of documenting the return shape, and it lists all eight returned fields including the useful already_existed and created flags. Combined with the idempotency explanation, an agent has enough to call and interpret results, though it omits default package path behavior and error cases.

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%, so the schema already documents name, density, friction, restitution, and package_path with types and defaults. The description's phrase 'surface/object properties' adds only a loose grouping and no syntax or unit detail beyond what the schema provides, so the baseline 3 applies.

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+resource ('Create and save a UPhysicalMaterial asset') and describes the optional property-setting scope. An agent can distinguish it from siblings like set_physical_material_properties or get_material_physical_material without opening either schema.

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?

Usage is implied by the verb and the idempotent behavior note ('if the asset already exists it is loaded'), which tells the agent it is safe to call without a pre-check. However, it names no alternative (e.g., the sibling set_physical_material_properties for modifying an existing asset) and gives no explicit when-not-to-use guidance.

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