Unleash Feature Flag MCP Server

Instructions

Implementation Reference

• src/tools/index.ts:57-77 (handler)

  Core handler function that executes the tool logic: parses input, makes POST request to Unleash API to create feature flag, returns response data.

  async function createFeatureFlag(
    params: z.infer<typeof CreateFeatureFlagSchema>
  ) {
    const { projectId, featureData } = CreateFeatureFlagSchema.parse(params);
    try {
      const response = await axios.post(
        `${UNLEASH_API_URL}/api/admin/projects/${projectId}/features`,
        featureData,
        {
          headers: {
            Authorization: `Bearer ${UNLEASH_AUTH_TOKEN}`,
            'Content-Type': 'application/json',
          },
        }
      );
      return response.data;
    } catch (error) {
      console.error('Error creating feature flag:', error);
      throw error;
    }
  }

• src/tools/schema.ts:8-22 (schema)

  Raw Zod input shape used for tool registration and validation of parameters: projectId and featureData structure.

  const RawCreateFeatureFlagShape = {
    projectId: z.string(),
    featureData: z.object({
      name: z.string(),
      description: z.string().nullable(),
      impressionData: z.boolean().nullable(),
      type: z.enum([
        'experiment',
        'kill-switch',
        'release',
        'operational',
        'permission',
      ]),
    }),
  };

• src/tools/schema.ts:49-49 (schema)

  Full Zod schema wrapping the raw shape, used in the handler for parsing.

  const CreateFeatureFlagSchema = z.object(RawCreateFeatureFlagShape);

• src/index.ts:41-49 (registration)

  MCP server tool registration: provides name, description, input schema, and thin wrapper that calls the handler and formats JSON response.

  server.tool(
    'createFeatureFlag',
    'Create a new feature flag',
    RawCreateFeatureFlagShape,
    async (args) => {
      const data = await createFeatureFlag(args);
      return { content: [{ type: 'text', text: JSON.stringify(data) }] };
    }
  );