Add 3D effects like reflection probes, decals, or fog volumes to a scene by specifying parent path and effect type.
Create ReflectionProbe, Decal, or FogVolume
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Node name | |
| size | No | Effect size {x,y,z} | |
| intensity | No | Effect intensity | |
| effectType | Yes | Type: reflection_probe, decal, fog_volume | |
| parentPath | Yes | Parent node path |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
There are no annotations, so the description carries the full burden of disclosing behavior. It only says 'Create', which implies mutation but does not explain side effects, required parent hierarchy, effect-specific constraints, or what happens to the scene after the call.
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 one short, direct sentence with no wasted words. It is efficient and front-loaded, though it could include a bit more context without becoming bloated.
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 creation tool with no annotations and no output schema, the description is too sparse. It does not explain the effect semantics, how the created node attaches to the parent path, or how parameters like size and intensity map to each effect type.
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 schema already documents all five parameters. The description adds little beyond naming the effect types; it does not clarify how size or intensity behave differently per effect type.
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 states a specific verb, 'Create', and names the exact resources it handles: ReflectionProbe, Decal, or FogVolume. This clearly distinguishes it from the many sibling tools that target other node types or operations.
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 implies usage: use this tool when you want to create one of the three listed 3D effect types. However, it gives no explicit guidance about alternatives or when not to use this tool, leaving comparison to siblings like game_spawn_node or add_node unaddressed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.