set_animation

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

The description adds significant behavioral context beyond the annotations: it specifies runtime-only preview lost on page reload, aligning with destructiveHint=true and idempotentHint=true. It also mandates user permission, which is a critical behavioral constraint not captured in annotations. No contradiction exists.

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 description is short and front-loaded with the purpose, followed by important caveats. It is efficient and easy to parse. A slight improvement could be combining repetitive 'runtime' mentions, but overall it is concise and structured well.

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?

Given the tool has 9 parameters and no output schema, the description adequately covers the runtime scope, persistence behavior, and user permission requirement. It does not explain error cases or interaction between parameters, but for a testing tool, it provides sufficient context for correct invocation.

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 baseline is 3. The description only lists parameter categories (mixer timeScale, action play/stop/pause/weight) but does not add new semantics beyond the schema's individual parameter descriptions. The tool's parameters are well-documented in the schema, so the description offers marginal additional value.

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 clearly states the tool controls animation parameters like mixer timeScale and action play/stop/pause/weight. It identifies the resource (animation) and verb (control). However, it does not explicitly differentiate from the sibling tool 'animation_details', which is for viewing animation info. The purpose is clear but lacks explicit sibling distinction.

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 description explicitly states the tool is 'Runtime only — for testing' and requires the agent to ask the user whether to apply changes only at runtime or also update source code. This provides clear guidance on when to use the tool and the needed user permission, effectively distinguishing use from persistent alternatives.

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