Create Caption Track
create_caption_trackImports reviewed SRT/VTT caption artifacts into the active Premiere sequence as a new caption track, or builds a local lecture-caption timing and review plan without contacting Premiere.
Instructions
Import an already reviewed caption artifact into the active sequence, or create a local lecture-caption timing and review workflow plan. Import rejects unsupported formats before host dispatch and reports structural success only when valid count readback shows exactly one new caption track. Unreadable or unexpected results preserve committed_unverified diagnostics; inspect before retrying. The planning action never contacts Premiere or changes an artifact.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| action | No | Use import (the default) to create a Premiere caption track, or plan_lecture_workflow for a read-only SRT/VTT timing and review plan. | import |
| item_id | No | For action import, the node ID or name of the imported caption project item (for example, an SRT file). Omit for plan_lecture_workflow. | |
| start_seconds | No | For action import, offset in seconds from the start of the sequence (default: 0). | |
| caption_format | No | For action import, Premiere caption format: subtitle (default), 608, 708, teletext, ebu, op42, or op47. | |
| artifact_format | No | For plan_lecture_workflow, the syntax of caption_content. VTT content must include its WEBVTT header. | |
| caption_content | No | For plan_lecture_workflow, the caller-owned SRT or VTT content to parse locally. The returned plan contains no caption text and does not write this artifact. | |
| idempotency_key | No | Optional client-chosen key (1-128 chars of A-Z a-z 0-9 . _ : -) for this intended edit. Pass a fresh key per edit and reuse it only when retrying that same edit, for example after a client-side timeout. A repeat with the same tool, key and arguments is not run again: while the first call is running it fails with IDEMPOTENCY_IN_PROGRESS (poll get_last_operations); after it finished it returns the original outcome marked replayed. A definite failure with nothing applied (receipt outcome not_applied) may be retried with the same key. Reusing a key with different arguments fails with IDEMPOTENCY_KEY_REUSED. Scoped to this MCP session (the stdio server process or one HTTP session) and held in memory only (200 keys, 1 hour); it does not survive a restart or reconnect. Read-only invocations are never deduplicated. | |
| expected_cep_target | No | Optional reviewed CEP sequence/clip identity and exact tick ranges. Checked before every generated command; UXP refuses this CEP-only guard. | |
| expected_project_path | No | Optional absolute saved-project path. Every generated CEP command refuses before its body when the active project differs or is unsaved. UXP commands refuse this CEP-only guard; local-only tools do not inspect Premiere. Omit to keep existing behavior. | |
| observed_offset_seconds | No | For plan_lecture_workflow, an editor-observed constant offset in seconds. Positive means captions currently appear later than intended; the preview proposes the inverse shift when safe. | |
| target_duration_seconds | No | For plan_lecture_workflow, optional intended sequence duration. A mismatch requires review unless proportional scaling is explicitly authorized. | |
| timing_tolerance_seconds | No | For plan_lecture_workflow, tolerance used to classify an offset or duration mismatch (default: 0.25 seconds). | |
| allow_proportional_scaling | No | For plan_lecture_workflow, explicitly permit a bounded timing-scale preview when the artifact end does not match target_duration_seconds. This still never rewrites a caption artifact. |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
| ok | Yes | Whether the tool completed successfully. | |
| data | No | Tool-specific result data when ok is true; on failure, diagnostic detail when the tool provides it. | |
| tool | Yes | The registered MCP tool name. | |
| error | No | Failure detail when ok is false. | |
| receipt | No | Versioned common mutation receipt; success never implies rendered verification. | |
| idempotency | No | Present when idempotency_key deduplicated this call: replayed is true when the original outcome was returned instead of running again. |