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

Adds substantial behavior beyond annotations: the composition is compiled and test-rendered before saving, failures return the error verbatim, the call returns a mediaRef for use with add_clips, and preview mode does not load media (slots render empty and the count is reported). These are exactly the non-obvious traits an agent needs before invoking.

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?

Dense but front-loaded, starting with the core definition and then the authoring constraints. There is mild redundancy — the 'motion' skill is pointed to twice (once for API surface, once for creative guidance) — but nearly every sentence carries actionable information.

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 13-parameter tool with nested objects and no output schema, the description covers the return value (mediaRef), the compile/test-render lifecycle, preview semantics, and the partsBoard pattern. An agent has enough to call it correctly without further exploration.

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 the baseline is 3, but the description adds real meaning: files maps names to TSX source with working relative imports, entry must `export default`, and schema keys (type string|number|color|boolean|select|mediaRef + default) become tweakable Inspector controls. It pushes the agent toward parameterizing colors, copy and media slots rather than hardcoding.

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 (creates) and resource (motion composition), then defines it concretely as an animated graphic authored as a React TSX component with examples (infographic, title, end-card, chart). This clearly distinguishes it from get_motion_composition and update_motion_composition in the sibling list.

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?

Gives explicit workflow guidance: read the 'motion' skill before writing, use preview:true with previewProps:{partsBoard:true} when the composition has UI-like parts, and retry after fixing compile errors. It lacks an explicit statement on when to use update_motion_composition versus creating a new one, which is the main missing routing cue.

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