vfx_apply

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

No annotations exist, so the description carries the full burden. It does disclose that this mutates Studio state, can create new instances, and requires a studio_id when multiple Studios are open — meaningful behavioral context. It says nothing about whether existing textures are overwritten, what happens with partially invalid targets, or what the call returns.

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 in the first clause and the rest is dense, useful parameter guidance with no filler. The run-on construction and stacked parentheticals make it slightly harder to scan than it needs to be.

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 6-parameter mutation tool with no annotations and no output schema, the description covers targeting, instantiation, per-class property mapping, and extra property setting. The notable remaining gap is the absence of any statement about return values or failure behavior, which matters given there is no output schema.

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?

At 50% schema coverage with 6 params (one nested), the description compensates well: it distinguishes bake (flipbook settings come from the recipe) from texture (no flipbook settings), explains targets vs create semantics, gives the default className, and states that properties uses the same format as set_properties. Only studio_id and parent path syntax are left to the schema.

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?

Opens with a specific verb and resource ("Puts an uploaded bake ... on instances in Studio") and enumerates the class-specific property each target type receives (ParticleEmitter flipbook fields, Texture on Beam/Trail/Decal, TextureID on MeshPart). That level of specificity clearly separates it from vfx_bake and vfx_upload, though it never names those siblings.

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?

It explains the internal mode split well — "targets: existing instances; create: { parent, name?, className? } makes a new one (default ParticleEmitter)" — and clarifies bake vs raw texture. It does not state prerequisites such as needing a prior vfx_bake/vfx_upload, nor when to prefer vfx_preview or vfx_viewer, so usage is implied rather than routed.

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