YouTube MCP Server

Instructions

Implementation Reference

• src/services/transcript.ts:24-42 (handler)

  The primary handler function that fetches the YouTube video transcript using the YoutubeTranscript library and returns it structured with videoId, language, and transcript data.

  async getTranscript({ 
    videoId, 
    language = process.env.YOUTUBE_TRANSCRIPT_LANG || 'en' 
  }: TranscriptParams): Promise<any> {
    try {
      this.initialize();
      
      // YoutubeTranscript.fetchTranscript only accepts videoId
      const transcript = await YoutubeTranscript.fetchTranscript(videoId);
      
      return {
        videoId,
        language,
        transcript
      };
    } catch (error) {
      throw new Error(`Failed to get transcript: ${error instanceof Error ? error.message : String(error)}`);
    }
  }

• src/types.ts:37-40 (schema)

  TypeScript interface defining the input parameters for the transcripts_getTranscript tool: videoId (required) and language (optional).

  export interface TranscriptParams {
    videoId: string;
    language?: string;
  }

• src/server.ts:81-98 (registration)

  Tool registration in the MCP server's ListToolsRequestHandler, defining the tool name, description, and input schema matching TranscriptParams.

  {
      name: 'transcripts_getTranscript',
      description: 'Get the transcript of a YouTube video',
      inputSchema: {
          type: 'object',
          properties: {
              videoId: {
                  type: 'string',
                  description: 'The YouTube video ID',
              },
              language: {
                  type: 'string',
                  description: 'Language code for the transcript',
              },
          },
          required: ['videoId'],
      },
  },

• src/server.ts:192-200 (handler)

  Dispatch handler in the MCP CallToolRequestHandler that casts arguments to TranscriptParams and calls the TranscriptService.getTranscript method, formatting the result as MCP content.

  case 'transcripts_getTranscript': {
      const result = await transcriptService.getTranscript(args as unknown as TranscriptParams);
      return {
          content: [{
              type: 'text',
              text: JSON.stringify(result, null, 2)
          }]
      };
  }