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

Goes beyond the annotations by disclosing that existing variants are preserved (reinforcing non-destructiveness), that the call returns the new variant plus an editor link, and that motion duration is read server-side from video length. This is meaningful behavioral context, though permission requirements are unstated.

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?

Four front-loaded sentences that each carry information: creation semantics, no-upload-needed, supported devices, preservation guarantee, and return value. No filler or redundancy.

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 a rich schema and an output schema, the description only needs to orient the agent, which it does by naming inputs, device scope, and return value. Minor gap: no explicit guidance on prerequisites or relationship to preview/update 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 every parameter thoroughly (device choices, preset meanings, outputRatio default, screenshotPath examples). The description largely restates device support and adds little syntax or semantics beyond what the schema provides, so baseline 3 applies.

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 and resource: creates a new mockup-animation variant from a scene preset plus screenshot/recording. The required-input framing implicitly distinguishes it from siblings like create_variant and update_mockup_animation, though no sibling is named 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?

Adds a helpful note that 'a dedicated mockup upload is not required' and that existing variants are preserved, which clarifies safe usage. But there is no explicit when-to-use guidance, no mention of preview_mockup_animation as a precursor, and no routing versus create_variant or generate_mockup_motion.

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