Langfuse MCP Server

Instructions

Implementation Reference

• src/tools/get-comment.ts:12-27 (handler)

  The main handler function that executes the 'get_comment' tool logic: calls the Langfuse client to retrieve the comment by ID, formats the response as MCP content, and handles errors.

  export async function getComment(
    client: LangfuseAnalyticsClient,
    args: GetCommentArgs
  ) {
    try {
      const data = await client.getComment(args.commentId);
      return {
        content: [{ type: 'text' as const, text: JSON.stringify(data, null, 2) }],
      };
    } catch (error: any) {
      return {
        content: [{ type: 'text' as const, text: `Error getting comment: ${error.message}` }],
        isError: true,
      };
    }
  }

• src/tools/get-comment.ts:4-8 (schema)

  Zod schema for validating the input arguments to the 'get_comment' tool, requiring a commentId string.

  export const getCommentSchema = z.object({
    commentId: z.string({
      description: 'The unique identifier of the comment to retrieve'
    }),
  });

• src/index.ts:836-849 (registration)

  Tool registration in the listTools handler: defines the 'get_comment' tool's metadata, description, and input schema for MCP discovery.

  {
    name: 'get_comment',
    description: 'Get detailed information about a specific comment.',
    inputSchema: {
      type: 'object',
      properties: {
        commentId: {
          type: 'string',
          description: 'The unique identifier of the comment to retrieve',
        },
      },
      required: ['commentId'],
    },
  },

• src/index.ts:1141-1144 (registration)

  Dispatch/registration in the callTool switch statement: parses arguments using the schema and invokes the getComment handler.

  case 'get_comment': {
    const args = getCommentSchema.parse(request.params.arguments);
    return await getComment(this.client, args);
  }

• src/tools/get-comment.ts:10-10 (schema)

  TypeScript type definition inferred from the getCommentSchema for type safety.

  export type GetCommentArgs = z.infer<typeof getCommentSchema>;