Mux a WAV file onto a previously registered video.
Args:
video_id: Id from `register_video` or `transcribe_audio`.
audio_path: Public HTTPS audio URL (hosted) or local file path (stdio).
output_path: Output filename hint (hosted) or MP4 path (stdio).
| Name | Required | Description | Default |
|---|---|---|---|
| video_id | Yes | ||
| audio_path | Yes | ||
| output_path | No | dubbed.mp4 |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses that the target video must already be registered and that output_path behaves differently in hosted vs stdio transports, but it says nothing about whether the source video is mutated or a new artifact is produced, whether existing output is overwritten, or what errors occur if the audio is not WAV.
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 core purpose is front-loaded in one sentence, followed by a compact Args block that adds real semantics rather than restating types. The Args block repeats parameter names already in the schema, but each line earns its place by adding transport-dependent meaning.
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?
An output schema exists, so return values need no explanation, and the three parameters are all documented. What is missing for a media-mutating tool with zero annotations is side-effect disclosure: whether the registered video is modified in place, whether output_path overwrites an existing file, and what happens on transport mismatch.
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 0%, so the description must supply all parameter meaning, and it does: video_id's provenance, audio_path's dual URL/path semantics by transport, and output_path's differing role as a filename hint vs an MP4 path. The only gap is that output_path's default value and the WAV-only constraint are not restated.
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?
"Mux a WAV file onto a previously registered video" names a specific operation (muxing audio onto an existing video) and its input resource, which clearly separates it from siblings like register_video or synthesize_audio. It stops short of explicitly naming an alternative, but the verb+resource pair is unambiguous.
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 implies the prerequisite that video_id must come from register_video or transcribe_audio, which is genuinely useful ordering guidance. However, it never states when to choose this tool over alternatives, what to do if the video was not registered, or any exclusion conditions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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