unreal_create_material_instance

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does say 'then save,' which signals persistence, but it omits important behavioral facts such as dryRun defaulting to true, overwrite/update semantics, editor-open requirements, or side effects of updating an existing material instance.

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 a single efficient sentence that front-loads the primary action and then lists the key parameter categories. There is no filler, repetition, or unnecessary detail.

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?

This is a 9-parameter mutation tool with nested objects, no annotations, and no output schema, yet the description is only one sentence. It fails to explain required path semantics, dry-run behavior, safety, or return expectations, leaving substantial ambiguity for correct invocation.

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 only 22%, so the description must compensate. It does add meaning by clarifying that scalars/vectors/textures are parameter dictionaries and that parent is the source material. However, it gives no semantic guidance for name, destination, dryRun, timeoutSeconds, or allowWithEditorOpen, including the required destination.

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 'Create (or update) a MaterialInstanceConstant from a parent material' — a specific verb, asset type, and source. It also names the parameter groups (scalar/vector/texture) and the save step, making it distinguishable from siblings like unreal_apply_material_to_actor.

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 use case is reasonably clear: use this tool when you need to create or update a material instance asset. However, there is no explicit when-to-use vs. when-not-to-use guidance, and no alternative tool is named, so the agent is left to infer the boundary against sibling tools.

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