create_substrate_slab_node

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

Goes well beyond the annotations: it explains that the operation saves the package, spells out what idempotency means concretely ('reuses an existing slab node on re-run'), and discloses the significant Substrate-disabled/compile caveat. This is exactly the mutation and failure-mode context the annotations cannot convey.

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 primary action, then adds the idempotency and Substrate caveats and a Returns summary. Slightly long, but every sentence carries information, and the Returns block compensates for the absent 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?

With no output schema, the description supplies the full return shape; with annotations covering safety, it still enriches behavior with the save/idempotency/Substrate caveats. An agent has everything needed to call it correctly and anticipate the compile limitation.

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 material_path and the optional node_pos_x/node_pos_y defaults. The description adds no additional parameter meaning, so 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 and resource ('Add a Substrate Slab BSDF node to a UMaterial asset') and clarifies it performs a real CreateMaterialExpression on the graph. This distinguishes it from siblings like connect_substrate_slab_to_material and set_substrate_slab_scalar.

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?

Provides useful context (works even when Substrate is disabled, but won't compile until enabled + editor restart) which functions as a precondition/caveat. However, it never names alternatives or states when to prefer this node-creation tool over other material-graph tools, leaving routing to inference.

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