diff --git a/src/frontend/src/types.ts b/src/frontend/src/types.ts
new file mode 100644
index 0000000..853de1a
--- /dev/null
+++ b/src/frontend/src/types.ts
@@ -0,0 +1,81 @@
+// API 类型定义
+
+export interface Task {
+  id: string;
+  title: string;
+  description: string | null;
+  status: string;
+  assignee: string | null;
+  assigned_by: string;
+  depends_on: string | null;
+  priority: number;
+  task_type: string | null;
+  risk_level: string | null;
+  must_haves: string | null;
+  output_path: string | null;
+  result_summary: string | null;
+  retry_count: number;
+  max_retries: number;
+  created_at: string | null;
+  updated_at: string | null;
+  completed_at: string | null;
+}
+
+export interface Project {
+  id: string;
+  name: string;
+  description: string | null;
+  status: string;
+  config: string | null;
+  created_at: string | null;
+  updated_at: string | null;
+}
+
+export interface Observation {
+  id: number;
+  task_id: string | null;
+  observer: string;
+  severity: string;
+  body: string;
+  resolved_by: string | null;
+  created_at: string | null;
+}
+
+export interface Event {
+  id: number | null;
+  task_id: string | null;
+  agent: string | null;
+  event_type: string;
+  detail: string | null;
+  created_at: string | null;
+}
+
+export interface DaemonStatus {
+  status: string;
+  tick_count: number;
+  uptime_seconds: number;
+  active_projects: number;
+  last_tick: string | null;
+}
+
+export interface ReviewResult {
+  verdict: string;
+  score: number;
+  gate: string;
+  needs_human: boolean;
+  results: ReviewStepResult[];
+}
+
+export interface ReviewStepResult {
+  step: string;
+  verdict: string;
+  score: number;
+  details: string;
+  suggestions: string[];
+}
+
+export type SSEEventData = {
+  event_type: string;
+  task_id?: string;
+  [key: string]: unknown;
+};