diff --git a/src/contracts/envelope.ts b/src/contracts/envelope.ts
new file mode 100644
index 0000000..ef21bdf
--- /dev/null
+++ b/src/contracts/envelope.ts
@@ -0,0 +1,23 @@
+/** 真源：BPOS-Document-Share/BPOS服务消息协议.md §1.3（v1.2）。本文件是手工同步副本。 */
+export type JsonValue = string | number | boolean | null | JsonValue[] | { [k: string]: JsonValue };
+export type JsonObject = { [k: string]: JsonValue };
+
+export interface Correlation {
+  taskId?: string;
+  workflowId?: string;
+  invocationId?: string;
+}
+
+export interface EventEnvelope<TType extends string = string, TPayload = JsonObject> {
+  id: string;              // 全局唯一消息 id，发布方生成
+  type: TType;             // 消息类型全名（即主题名）
+  correlation: Correlation;
+  payload: TPayload;
+  occurredAt: string;      // ISO-8601
+  trace?: string;          // W3C traceparent
+}
+
+export interface CommandEnvelope<TType extends string = string, TPayload = JsonObject>
+  extends EventEnvelope<TType, TPayload> {
+  idempotencyKey: string;  // BUS-01
+}