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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds context those hints cannot convey: it is a synchronous GET with no request body, it is a free discovery endpoint that charges no credits, and it describes the shape of the returned arrays. That is exactly the kind of cost and transport information an agent needs before calling.

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?

The most important facts — what is listed and what it returns — are front-loaded, and each sentence carries content. The final sentence is somewhat dense with sibling references and the parenthetical field enumeration is long, but nothing is truly redundant.

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 takes on the burden of explaining return values and does so field by field, including the deduplicated perspectives array and directions list. Combined with the cost and transport notes, an agent has everything needed to call this correctly.

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?

There are zero parameters, so the baseline is 4 and there is no parameter semantics to add. The description does usefully describe the response fields (id, name, category, description, duration, preview_url), which partially substitutes for the missing parameter detail.

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 opens with a specific verb and resource ("List the available animation presets") and immediately enumerates the returned dimensions (perspectives, eight compass directions). It also names the sibling tools it complements, so an agent can distinguish it from transferMotion or animateSprite without opening any 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?

It states an explicit use case: obtain preset_id, perspective, and direction values that transferMotion requires, plus preset names for animating. It then routes the agent to the concrete downstream alternatives (transferMotion, animateSprite, animate3DModelPreset), leaving nothing to inference.

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