get_material_layer_stack

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavior context beyond that: the ordering guarantee of the returned layers, the interpretation of has_layers, and the warning that indices are meaningless on non-layered materials.

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?

Purpose is front-loaded, the usage caveat follows immediately, and the inline Returns block is justified because no output schema exists. Minor redundancy between 'has_layers telling you whether the material is layered' and the has_layers field in the Returns block, but nothing egregious.

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 return shape itself (fields, types, nesting), plus the semantic meaning of has_layers and the ordering of layers - everything an agent needs to call it and interpret the result for a one-parameter read tool.

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 coverage is 100% with a single documented parameter, so the schema already carries the semantics. The description implies the path points at a material instance rather than a base material, but adds no format or syntax detail beyond the schema. Baseline 3 is correct here.

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 - reading a material's layer stack - and enumerates exactly what is returned (layer functions and blend functions, in order). An agent can distinguish this from the many sibling get_material_* tools without opening the 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?

Gives explicit timing and rationale: 'Check this before any set_material_layer_parameter call -- on a non-layered material the layer indices mean nothing.' That is a clear when-to-use rule with a consequence. It does not, however, address the closest read sibling (get_material_layer_info / get_material_layer_parameter), so the alternative-selection guidance is incomplete.

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