This API must be called after adding audio(s); The add audio call gives you URLs to upload, and you complete a PUT request to those URLs.
Once that is done, calling this initiates the process to actually add the subtitle to the video.
| Name | Required | Description | Default |
|---|---|---|---|
| asset_ID | Yes | An asset id for the previously created asset. | |
| upload_responses | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare that this is a non-read-only, non-idempotent, non-destructive operation. The description adds useful prerequisite workflow context and says the call initiates a process, but it does not disclose permissions, side effects, or what happens to existing state.
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 short and front-loads the prerequisite workflow. Its structure is efficient, though the subtitle reference in the final sentence introduces unnecessary confusion.
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 not be explained, and annotations cover the safety profile. Still, the description leaves the audio/subtitle scope ambiguous and does not compensate for the partial parameter documentation, leaving gaps for correct invocation.
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?
The description does not mention either parameter. With only 50% schema description coverage, it should explain or reinforce what asset_ID and upload_responses represent, especially since the upload_responses array itself is undocumented at the top level.
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 identifies a completion step that follows audio upload and a PUT to returned URLs, so the general purpose is inferable. However, it says the call 'actually add[s] the subtitle to the video,' which is confusing for an audio-upload completion tool and does not clearly distinguish it from siblings like complete_subtitle_upload or upload_subtitles.
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 clearly states the prerequisite sequence: add audio first, receive URLs, complete PUTs to those URLs, then call this tool. It does not name alternative tools or explicit when-not conditions, which keeps it from a 5.
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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