Creates a caption track in a Premiere Pro sequence from an existing .srt, .scc, .mcc, .xml, or .stl caption file.
Create a caption track from an existing caption file (.srt, .scc, .mcc, .xml, .stl)
| Name | Required | Description | Default |
|---|---|---|---|
| start | No | Sequence time where the file's 00:00:00 lands (default 0) | |
| format | No | ||
| filePath | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full disclosure burden and delivers almost nothing beyond 'this creates something.' It does not say which sequence/track receives the track, whether an active sequence is required, what happens on an unsupported or malformed file, or whether existing caption tracks are replaced.
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?
A single front-loaded sentence with the action first and the supported formats in parentheses; no filler. It is efficient, though its brevity is partly under-specification rather than discipline.
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 mutation tool with zero annotation coverage, no output schema, and two of three parameters undocumented in the schema, the description is too thin. An agent cannot tell what the call requires of project state (active sequence, target track) or what happens when the format argument conflicts with the file extension.
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 only 33% — only 'start' is described — so the description must compensate. It adds real value by enumerating the accepted file extensions for filePath, but leaves the 'format' enum (subtitle, cea608, cea708, teletext, ebu, op42, op47) and the relationship between file extension and that enum completely unexplained.
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 resource — 'Create a caption track' — plus the source of truth ('an existing caption file'), which implicitly distinguishes it from add_captions and add_text_captions that generate caption content rather than import it. The distinction is inferable but never stated by name, so it stops short of a 5.
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 phrase 'from an existing caption file' implies the use case (you already have a .srt/.scc/etc.) versus generating captions through siblings, but no alternative is named and no when-not-to-use condition is given. Usage must be inferred from the prepositional phrase alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.