create_prim

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

Annotations already declare non-readonly, non-destructive, closed-world, so the bar is lower, and the description still adds real value: the existing-prim conflict semantics (type preserved, mismatched type refused) are non-obvious and prevent a failed call. It omits whether the parent path must exist, whether the creation is persisted or requires save_scene, and how partial failures behave.

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?

Three short sentences, front-loaded with the core action, and no filler. The type enumeration earns its place as a discoverable hint. Minor structural noise from stray indentation and blank lines keeps it from 5.

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?

With an output schema present, the description needn't explain return values, and annotations cover safety. What remains necessary for correct invocation – available types, the usd_path alternative, and the existing-prim collision rule – is all stated, making this complete for a creation tool.

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 100%, so the schema already documents scale, position, rotation, usd_path, prim_path, prim_type, and enable_physics thoroughly. The description adds only one semantic not in the schema – that usd_path is an alternate mode that substitutes for prim_type. Baseline 3 is correct when the schema does the heavy lifting.

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 first line gives a specific verb and resource ("Create a new prim in the scene") that an agent can match against clone_prim or create_robot without opening the schema. It then enumerates the concrete prim types, grounding the abstraction. It stops short of 5 because it never explicitly contrasts itself with the nearest sibling (clone_prim) or create_robot.

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?

Usage conditions are genuinely stated: choose a prim_type, or alternatively supply usd_path to reference a USD file. The conflict rule ("A prim already at prim_path keeps its type: one of another type is refused") tells the agent the preconditions under which the call will fail. No explicit when-not or named sibling alternative, so not a 5.

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