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

Goes well beyond the destructiveHint=true annotation by quantifying cost (~1 credit per rendered second), listing what is free (key frames, voice, stitching), and promising a full refund on failure. It also discloses preconditions that cause refusal, which annotations alone 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?

The action/cost guarantee is front-loaded and the bulleted mode list is easy to scan without waste. It runs long and the closing voice-recording parenthetical is a slight detour, but every section still carries operational 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 destructive, credit-spending mutation with no output schema, the description covers cost, refund behavior, preconditions, mode semantics and fallbacks. Nothing an agent needs to invoke it safely is missing.

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 already 100%, yet the description is the only place that explains what each enum value of mode actually does downstream (rewrite prompts vs. new key frames vs. re-roll clips) and what prior edit each requires. That is genuine meaning beyond the enum literals.

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 first sentence names the exact verb and resource (re-render scenes, then re-stitch) and constrains scope to a FINISHED video, which implicitly separates it from regenerate_video and edit_scene. An agent knows immediately what state the video must be in.

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?

It gives an explicit selection rule per mode ('narration' after narration/visual edits or set_scene_audio, 'images' after keyframe='variant', 'clips' after prompt/keyframe/duration edits), states the refusal condition for unapplied edits, and names a concrete alternative path (get_audio_upload_page then set_scene_audio) instead of further re-rolls.

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