add_usd_internal_reference

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

Annotations already declare readOnly=false, destructive=false, idempotent=false, so the mutation profile is known. The description adds the same-stage constraint and the return shape, but stays silent on error conditions, ordering/replace behavior, and whether the stage must be open – so it adds limited behavioral value beyond annotations.

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?

Two tight sentences plus a compact return shape; the scoping constraint is front-loaded and every element earns its place with no repetition of schema content.

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 no output schema, the description usefully supplies the return fields (added, position, errors), which the agent would otherwise lack. It could go further on failure behavior, but for a single-shot add tool it is largely complete.

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 all four parameters are already documented (including the 'same stage' meaning of target_prim_path). The description largely restates that constraint and adds no extra syntax or default details beyond the schema, so baseline 3 applies.

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+resource ('add an internal reference composition arc') and immediately scopes it as 'references another prim inside the SAME stage', which distinguishes it from the sibling add_usd_reference by ruling out the asset_path case. An agent can differentiate it without opening the schema.

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 'internal ... SAME stage; no asset_path needed' phrasing makes the selecting condition clear, implicitly contrasting with add_usd_reference for cross-asset references. It gives clear context but names no alternative explicitly and states no exclusion.

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