add_material_node

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

Annotations already declare the mutation profile (readOnly=false, destructive=false, openWorld=false). The description adds that it returns the node id and parameters, and flags the OpenPBR limitation, but says nothing about the need for commit_material_changes/undo_material_changes or whether adding a node mutates the live material.

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?

Short, but the phrasing is fragmented and the line wrapping plus the ambiguous 'd'une copie' force the reader to re-parse. The most important constraint (no OpenPBR) is buried at the end rather than front-loaded.

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?

An output schema exists, so return values need not be described. However, for a graph-mutating tool with zero schema descriptions, the definition leaves the meaning of 'material' and 'name' and the commit/undo workflow unexplained.

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 0%, so the description must compensate. It does this well for 'type' (lux constants such as SHADER_TYPE_SPOTS vs. type names like 'lux_spots'), but leaves 'material' and 'name' entirely unexplained, so a third of the parameters remain undocumented.

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: adds a node to a material graph, and names the accepted type values. It does not explicitly distinguish itself from siblings like connect_material_nodes or remove_material_node, though the verb makes the difference inferable.

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 an explicit when-not rule: no OpenPBR constant should be used here, instead copy an OpenPBR_* material from the library. That is real routing guidance, though it does not cover when to add a node versus editing parameters directly.

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