create_material_layer_blend

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

Annotations already declare idempotentHint=true, readOnlyHint=false, and destructiveHint=false; the description goes further to define what idempotency means here ('any material function already at that path is returned as is, whatever its class') and discloses the save-failure contract ('Success even when the save fails; read saved and save_error'). This is useful context beyond the annotations, though permissions/auth requirements are not 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?

Front-loads the core action in the first sentence, then adds the idempotency and save-failure semantics. Dense but each clause carries information; the Returns block is compact and useful given there is no output schema.

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?

For a two-parameter creation tool with no output schema, the description supplies the return shape, idempotency behavior, and save-failure handling, which is nearly complete. It could be strengthened by stating permission/prerequisite requirements and distinguishing usage from sibling material creators.

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 both parameters are already documented including the trailing-slash note. The description adds the package_path/name composition relationship but little else beyond the schema, so the baseline 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?

States a specific verb (Creates), a precise resource (UMaterialFunctionMaterialLayerBlend asset with usage MaterialLayerBlend), the target location (package_path/name), and the save side effect. This clearly distinguishes it from siblings like create_material_layer, create_material_function, and create_material.

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 notes it behaves 'like the editor factory' and documents idempotent re-run behavior, which implies when it is appropriate, but it never names an alternative tool or states exclusions for when NOT to use it versus the other material-creation siblings.

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