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

With no annotations provided, the description carries the full burden and does well by disclosing asynchronous behavior, immediate job_id return, native audio, automatic engine fallback for reliability, and cost dependence on quality/duration. It lacks specifics on failure modes or the fallback chain's exact behavior, but covers the core operational traits.

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 four concise sentences, each adding essential information: purpose, workflow/async polling, reliability features, and cost structure. Every sentence earns its place with 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?

The description combined with a fully self-describing schema (5 params, enums, defaults) provides comprehensive guidance for invoking the tool: input requirements, async flow, follow-up polling, and pricing. It could mention the prerequisite of a previous generate_fashion_image result, but that is already in the schema's source_image_url description, so the lack is minor.

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 baseline is 3. The description's mention of costs for 720p/1080p partially duplicates the schema's own parameter descriptions, adding only a summarized pricing overview rather than new semantic meaning beyond the schema.

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 'Submit an async video generation job from an existing image', providing a specific verb and resource that distinguishes it from sibling tools like generate_fashion_image and check_video_status. It precisely captures the tool's primary function.

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 provides clear usage context by explaining the async pattern: it returns a job_id immediately and instructs to call check_video_status for completion. However, it does not explicitly contrast with alternatives like generate_multi_angle or state when not to use, though the input requirement 'from an existing image' implies its applicability.

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