Flipt MCP Server

Implementation Reference

• src/index.ts:234-278 (registration)

  Registers the 'create_flag' MCP tool with input schema and execution handler using McpServer.tool()

  server.tool(
    'create_flag',
    {
      namespaceKey: z.string().min(1),
      key: z.string().min(1),
      name: z.string().min(1),
      description: z.string().optional(),
      enabled: z.boolean().optional(),
      type: z.enum(['VARIANT_FLAG_TYPE', 'BOOLEAN_FLAG_TYPE']),
    },
    async args => {
      try {
        const flag = await fliptClient.createFlag(
          args.namespaceKey,
          args.key,
          args.name,
          args.description,
          args.enabled,
          args.type
        );
        return {
          content: [
            {
              type: 'text',
              text: JSON.stringify(flag, null, 2),
            },
          ],
          _meta: {
            uri: `flipt://namespaces/${args.namespaceKey}/flags/${args.key}`,
          },
        };
      } catch (error: any) {
        console.error('Error creating flag:', error);
        return {
          content: [
            {
              type: 'text',
              text: `Failed to create flag: ${error.message}`,
            },
          ],
          isError: true,
        };
      }
    }
  );

• src/index.ts:244-277 (handler)

  Handler function that executes the create_flag tool: validates args (via schema), calls fliptClient.createFlag, formats response or error for MCP

  async args => {
    try {
      const flag = await fliptClient.createFlag(
        args.namespaceKey,
        args.key,
        args.name,
        args.description,
        args.enabled,
        args.type
      );
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify(flag, null, 2),
          },
        ],
        _meta: {
          uri: `flipt://namespaces/${args.namespaceKey}/flags/${args.key}`,
        },
      };
    } catch (error: any) {
      console.error('Error creating flag:', error);
      return {
        content: [
          {
            type: 'text',
            text: `Failed to create flag: ${error.message}`,
          },
        ],
        isError: true,
      };
    }
  }

• src/index.ts:236-242 (schema)

  Zod schema defining input parameters for the create_flag tool

  {
    namespaceKey: z.string().min(1),
    key: z.string().min(1),
    name: z.string().min(1),
    description: z.string().optional(),
    enabled: z.boolean().optional(),
    type: z.enum(['VARIANT_FLAG_TYPE', 'BOOLEAN_FLAG_TYPE']),

• src/services/fliptClient.ts:134-160 (helper)

  FliptClient.createFlag helper method: maps tool type to API enum and calls generated FlagsServiceApi.createFlag to create the flag in Flipt

  async createFlag(
    namespaceKey: string,
    key: string,
    name: string,
    description?: string,
    enabled?: boolean,
    type?: string
  ) {
    try {
      const flagType =
        type === 'VARIANT_FLAG_TYPE'
          ? CreateFlagRequestTypeEnum.VariantFlagType
          : CreateFlagRequestTypeEnum.BooleanFlagType;
  
      const response = await this.flagsApi.createFlag(namespaceKey, {
        key,
        name,
        description,
        enabled: enabled ?? true,
        type: flagType,
      });
      return response;
    } catch (error) {
      console.error('Error creating flag:', error);
      throw error;
    }
  }