add_usd_reference

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

Annotations already declare the full safety profile (not read-only, non-destructive, not idempotent, closed world), so the bar is lower. The description usefully discloses the return payload shape, but adds little behavioral context beyond the schema - e.g., no notes on permissions, edit-target requirements, or side effects on existing references.

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 sentences with the purpose front-loaded and the return shape clearly separated. No wasted filler, though the parenthetical mapping notation is slightly dense.

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 100% schema coverage and an inline description of the return value (no output schema exists), the definition gives an agent enough to call the tool correctly. Minor gaps remain around when to prefer it over the other add_usd_* composition tools.

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 thoroughly, including position enum values and prim_path_for_target behavior. The description reinforces the asset_path/target mapping but adds no syntax or format detail beyond the schema, so the baseline 3 holds.

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 ('Add') and resource ('external reference composition arc to a prim') and clarifies the mapping direction (asset_path -> target prim). The word 'external' implicitly distinguishes it from the sibling add_usd_internal_reference, though it never names that sibling explicitly.

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 is implied by the composition semantics (referencing an external layer onto a prim), but there is no explicit when-to-use vs add_usd_internal_reference or add_usd_payload, and no stated prerequisites or ordering constraints.

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