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

With annotations only covering safety flags (readOnly=false, destructive=false, openWorld=true), the description carries real behavioral weight: it costs one text generation of the publisher's credits, may take ~2 minutes and then returns a generation id that must be re-passed to avoid double charging, and library-external refs are silently replaced (listed in `repaired`). It also states there is no server render — the player edits and exports the MP4 on-device.

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?

Purpose is front-loaded in the opening clause and every subsequent sentence carries operational information (cost, timeout, repair, return shape, no server render). It is one dense block with heavy backticked jargon, which costs some readability, but there is little filler to cut.

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?

No output schema exists, yet the description explains the return value is a video PACKAGE ({ spec, assets }), what the `next` field instructs, what `repaired` contains, and the optional `link`. For a paid, possibly long-running, open-world generation tool, that is the full picture an agent needs to call and follow up correctly.

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; the description still adds meaning by explaining that the cast is fitted to the format, that `mode`'s unique path emits generate_asset instructions while library refs get repaired, and that title_id yields a `link` into the app's editor when the game has the video studio. These are behavioral consequences of parameters rather than restatements.

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 artifact: turns an idea into a VideoSpec (format, scene, characters, lines, captions) plus the plan, built from the studio library. It distinguishes itself from the single-asset generators (generate_video, generate_asset) by describing the multi-element spec/plan output and by pointing to list_video_formats and search_assets for inputs.

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?

Clearly frames the workflow (idea → spec + plan, then hand the returned `package` and slot to generate_asset) and points at list_video_formats/search_assets for prerequisites. It also explains what happens when refs fall outside the library (repaired) and how to resume with generation_id. It stops short of explicitly naming when to prefer generate_video or remix_video instead, so no true exclusion guidance.

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