Kaltura MCP Server

Instructions

Implementation Reference

• src/kaltura_mcp/tools/assets.py:32-94 (handler)

  The main handler function that executes the list_caption_assets tool logic, querying the Kaltura API for caption assets associated with a media entry ID.

  async def list_caption_assets(
      manager: KalturaClientManager,
      entry_id: str,
  ) -> str:
      """List all caption assets for a media entry."""
      if not validate_entry_id(entry_id):
          return json.dumps({"error": "Invalid entry ID format"}, indent=2)
  
      if not CAPTION_AVAILABLE:
          return json.dumps(
              {
                  "error": "Caption functionality is not available. The Caption plugin is not installed.",
                  "entryId": entry_id,
              },
              indent=2,
          )
  
      client = manager.get_client()
  
      try:
          # Create filter for caption assets
          filter = KalturaCaptionAssetFilter()
          filter.entryIdEqual = entry_id
  
          # List caption assets
          result = client.caption.captionAsset.list(filter)
  
          captions = []
          for caption in result.objects:
              caption_data = {
                  "id": getattr(caption, "id", None),
                  "entryId": getattr(caption, "entryId", None),
                  "language": safe_serialize_kaltura_field(getattr(caption, "language", None)),
                  "languageCode": safe_serialize_kaltura_field(
                      getattr(caption, "languageCode", None)
                  ),
                  "label": getattr(caption, "label", None),
                  "format": safe_serialize_kaltura_field(getattr(caption, "format", None)),
                  "status": safe_serialize_kaltura_field(getattr(caption, "status", None)),
                  "fileExt": getattr(caption, "fileExt", None),
                  "size": getattr(caption, "size", None),
                  "createdAt": datetime.fromtimestamp(caption.createdAt).isoformat()
                  if caption.createdAt
                  else None,
                  "updatedAt": datetime.fromtimestamp(caption.updatedAt).isoformat()
                  if caption.updatedAt
                  else None,
                  "accuracy": getattr(caption, "accuracy", None),
                  "isDefault": safe_serialize_kaltura_field(getattr(caption, "isDefault", None)),
              }
              captions.append(caption_data)
  
          return json.dumps(
              {
                  "entryId": entry_id,
                  "totalCount": result.totalCount,
                  "captionAssets": captions,
              },
              indent=2,
          )
  
      except Exception as e:
          return handle_kaltura_error(e, "list caption assets", {"entryId": entry_id})

• src/kaltura_mcp/server.py:434-447 (schema)

  MCP tool schema definition including input schema (entry_id required) and usage description.

  types.Tool(
      name="list_caption_assets",
      description="Find all CAPTIONS/SUBTITLES for a video. USE WHEN: Checking if video has captions, finding available languages, preparing for accessibility, getting transcript. RETURNS: List of caption files with languages, formats (SRT/VTT), IDs. EXAMPLE: 'Does video 1_abc123 have captions?', 'List subtitle languages available'. First step before getting caption content.",
      inputSchema={
          "type": "object",
          "properties": {
              "entry_id": {
                  "type": "string",
                  "description": "Video to check for captions (format: '1_abc123')",
              },
          },
          "required": ["entry_id"],
      },
  ),

• src/kaltura_mcp/server.py:521-522 (registration)

  Tool handler registration and dispatch in the MCP server's call_tool method.

  elif name == "list_caption_assets":
      result = await list_caption_assets(kaltura_manager, **arguments)

• src/kaltura_mcp/tools/__init__.py:13-18 (registration)

  Import and export of the list_caption_assets function in the tools module for use across the package.

  from .assets import (
      get_attachment_content,
      get_caption_content,
      list_attachment_assets,
      list_caption_assets,
  )