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

The description adds meaningful behavioral context beyond annotations: it is paid and priced by size, the first animation is free, animations do not create a new version, and the caller should poll the job. This goes well beyond the readOnly/idempotent/destructive flags and helps the agent set expectations.

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 compact sentences, each carrying distinct value: the core operation, pricing/free-first behavior, and polling instruction. Content is front-loaded and there is no filler.

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 paid, asynchronous animation mutation, the description covers the key operational facts: pricing model, version behavior, and how to track the job. Required parameters are documented in the schema and an output schema exists, so return shape does not need to be in the description.

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 seven parameters. The description adds no substantial parameter-level detail beyond the schema; the mention of passing an animation name to change it mirrors what the animation parameter description already says.

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 and resource: 'Add an animation to a Low-Poly model version, or change an existing one.' It further distinguishes the operation by noting animations attach to the version and do not create a new version, which separates it from sibling operations like generation or revision.

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 clearly frames when to use this tool: to add or change an animation, and says to poll get_lowpoly_job afterward. It does not explicitly enumerate alternatives or exclusion criteria, but the context of what counts as an animation operation is clear.

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