rhino_layer_set_material

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

The readOnlyHint=false annotation already signals mutation; the description adds genuinely useful behavior beyond it: the in-document material table is read-only, materials must pre-exist, and layer-source objects inherit the bound material. This explains the operational constraint and prerequisite ordering well, though it does not cover failure cases or overwrite behavior.

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?

The description is compact and front-loaded: the core purpose is stated in sentence one, followed by a tightly scoped constraint note. Every sentence earns its place, and the bridge-only caveat is necessary because it forces the correct call sequence.

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 mutation tool with one args object and an output schema, the description covers the essential workflow: what the tool does, the prerequisite material creation, and the inheritance effect. It falls slightly short on explaining the material selection parameters, but the output schema and nested property descriptions partially fill that gap.

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 reported at 0%, and the description does not compensate for this gap. It never mentions material_name/material_index mutual exclusivity, the doc_id default, or how to select which material to bind. The nested schema properties carry some descriptions, but the tool description itself adds no parameter-level meaning, and the agent is left without guidance on the two alternative selection modes.

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?

The description opens with a specific verb+resource statement: 'Bind a render material to a layer so layer-source objects inherit it.' This clearly states both the action and the effect, and the layer-level scope distinguishes it from object-level material siblings like rhino_material_assign, rhino_set_object_material, and rhino_assign_material_to_object.

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 gives explicit sequencing guidance: 'Use rhino_material_create first to define the material,' and explains why in the bridge-only context. It does not explicitly state when not to use this tool or name the object-level alternatives, but the layer-scope is clear enough that the agent can infer the boundary.

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