set_material_layer_stack

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

Annotations already declare destructiveHint=true and idempotentHint=true. The description adds critical context the annotations cannot: order is significant, layers are addressed by index downstream, and re-stacking renumbers existing per-layer values. It also documents the return shape, which helps for a mutation tool.

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-loaded with the core action and example, followed by the ordering caveat and readback guidance. Dense but every sentence carries weight; no filler.

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 destructive, indexed mutation tool, it covers what it does, why ordering matters, the downstream index dependency, the readback sibling, and the return shape. Nothing essential to calling it correctly is missing.

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 baseline is 3, but the description adds real meaning beyond the schema: it explains that layers and blends are function-path lists composed in order and that ordering/indexing matters for downstream per-layer parameters.

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 (define/set) plus resource (the layer and blend functions a layered material instance stacks) and clarifies the intent with a concrete example (base + dirt + snow). It is clearly distinguishable from sibling tools like set_material_layer_parameter and get_material_layer_stack.

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?

Explains when to use it (composing a surface out of reusable layer functions rather than editing the base material graph) and routes the agent to get_material_layer_stack for readback and set_material_layer_parameter for downstream edits. Does not state exclusions, but the context is unambiguous.

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