Dub video

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

Annotations are neutral (readOnlyHint: false, destructiveHint: false), so the description carries the burden of disclosing behavior. It clearly states that it does NOT re-render, preserves visuals/timing/edit, transcribes/translates/re-voices/lip-syncs, and returns the served URL. It also discloses that it is paid. This adds significant behavioral context beyond annotations, though it omits potential limitations like processing time or input format constraints.

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 moderately long but every sentence earns its place: it explains the mechanism, the simple invocation, the script override nuance, and the cost/return. Key facts (no re-render, pass video+language, paid, returns URL) are front-loaded, making it skimmable. A slight trim could tighten it, but it remains focused.

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 no output schema, the description correctly specifies that it returns 'the served URL of the localized video.' It covers all four parameters, the cost, and the behavioral specifics. Missing details like asynchronous processing or video size limits are non-essential for basic usage, so the description is virtually complete for an agent to invoke it 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 description coverage is 100%, so each parameter already has a description. The tool description enhances this by explaining the script parameter's override purpose ('pass script only to override what it heard') and adding nuance about the voice parameter's default selection. This goes beyond mere schema repetition, adding practical guidance without being redundant.

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 states a specific verb ('localize') and resource ('finished video') with a clear outcome (transcribed, translated, re-voiced, lip-synced back onto the same footage). It distinctly differentiates from siblings like clip_video or edit_video by focusing on language localization without re-rendering, leaving no ambiguity about what the tool does.

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 explicitly tells the agent to 'Just pass the video and the language', making the core usage obvious. It also provides a conditional for the script parameter (use only when auto-transcript fails) and mentions the tool is paid, which is a cost guideline. However, it does not explicitly contrast with alternative tools, though no direct sibling exists that performs dubbing, so the context is sufficiently clear.

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