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

Adds substantial context beyond the annotations: per-type credit costs charged from the account, automatic refund on failed render, 10-15 minute render latency, and the async queue-then-poll workflow. These are exactly the facts an agent needs that readOnlyHint/destructiveHint cannot convey.

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?

Front-loaded with the core action and scoped well, but the clip_type inventory is a dense run-on of nested parentheses that takes effort to parse. Every sentence carries information, so nothing is wasted, but formatting as a list would improve scanability.

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?

Covers the full lifecycle: cost, latency, refund behavior, format constraints, and next step (polling list_clips), which compensates for the absence of an output schema. Only missing piece is any guidance on the count parameter and whether repeated calls are deduplicated (idempotentHint=false is not addressed).

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 67%, and the description adds real meaning where it matters most: the format family must match clip_type (story for ai_story/ad, ugc for avatar, none for montage), which is a constraint the schema text only partly implies. It also explains clip_type values with costs. The count parameter is never mentioned, leaving its 1-5 range purely to 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?

Opens with a specific verb and resource plus the output format: queue vertical 9:16 clips (TikTok, Reels, Shorts) of one catalog product. The four clip_type variants are each described concretely, so an agent knows exactly what artifact it gets and can separate this from siblings like create_video or create_image.

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 selection criteria per clip_type with credit costs (montage 1, ai_story 6, avatar 12, ad 6), states that ad is legacy and equivalent to ai_story, and names the follow-up step (poll list_clips for download links). Small gap: it doesn't say when to prefer this over create_video/make_talking_photo, but the internal routing guidance is unusually strong.

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