YouTube MCP Server

Instructions

Implementation Reference

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

  Core implementation of the getTranscript method in TranscriptService class, which fetches the transcript using YoutubeTranscript.fetchTranscript(videoId). Note that language param is captured but not passed to the library.

  async getTranscript({ 
    videoId, 
    language = process.env.YOUTUBE_TRANSCRIPT_LANG || 'en' 
  }: TranscriptParams): Promise<unknown> {
    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 parameters for the transcript service methods: videoId (required) and language (optional).

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

• src/server-utils.ts:177-197 (registration)

  Registration of the 'transcripts_getTranscript' MCP tool, including title, description, Zod input schema matching TranscriptParams, and thin async handler that wraps TranscriptService.getTranscript and formats response as MCP content.

  server.registerTool(
      'transcripts_getTranscript',
      {
          title: 'Get Video Transcript',
          description: 'Get the transcript of a YouTube video',
          annotations: { readOnlyHint: true, idempotentHint: true },
          inputSchema: {
              videoId: z.string().describe('The YouTube video ID'),
              language: z.string().optional().describe('Language code for the transcript'),
          },
      },
      async ({ videoId, language }) => {
          const result = await transcriptService.getTranscript({ videoId, language });
          return {
              content: [{
                  type: 'text',
                  text: JSON.stringify(result, null, 2)
              }]
          };
      }
  );