diff --git a/README.md b/README.md
index c3df496..9eabd88 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,12 @@
 
 Gaza 是一个协议优先、跨平台的多 Teamserver 桌面工作台。当前仓库包含可运行的首个项目骨架，重点验证 Teamserver 工作区和标签页隔离模型。
 
+## 标准协议模型
+
+`src/protocol` 定义 GUI 与兼容 Teamserver 之间的首版强类型模型，包括 Teamserver、Project、Session、Capability、Task、Event、Artifact 和 Audit。该模块不包含网络请求、认证或私有 C2 适配。
+
+`ServerId`、`ProjectId`、`SessionId` 等采用品牌类型，避免在编译期误用不同层级 ID；枚举允许未来服务端新增值，解析器保留未知枚举和扩展字段。迁移现有界面数据时可从 `src/protocol/fixtures` 引入最小演示 fixture。
+
 ## 技术栈
 
 - Tauri 2（桌面容器）
diff --git a/src/protocol/fixtures/index.ts b/src/protocol/fixtures/index.ts
new file mode 100644
index 0000000..d29ac73
--- /dev/null
+++ b/src/protocol/fixtures/index.ts
@@ -0,0 +1,18 @@
+import type { Session } from "../model";
+
+/** UI 迁移期可直接使用的最小 Session fixture。 */
+export const demoSession = {
+  server_id: "demo-server",
+  project_id: "demo-project",
+  session_id: "demo-session",
+  name: "演示会话",
+  state: "ONLINE",
+  hostname: "demo-host",
+  username: "operator",
+  os: "linux",
+  architecture: "amd64",
+  first_seen_at: "2026-08-03T00:00:00Z",
+  last_active_at: "2026-08-03T00:00:05Z",
+  tags: ["fixture"],
+  capabilities: ["session.overview"],
+} as unknown as Session;
diff --git a/src/protocol/model.ts b/src/protocol/model.ts
new file mode 100644
index 0000000..82e2cae
--- /dev/null
+++ b/src/protocol/model.ts
@@ -0,0 +1,166 @@
+/** 协议对象允许保留服务端新增字段，GUI 不应因未知字段而拒绝整个对象。 */
+export interface Extensible {
+  readonly [extension: string]: unknown;
+}
+
+declare const brand: unique symbol;
+export type Brand<Value, Name extends string> = Value & { readonly [brand]: Name };
+export type ServerId = Brand<string, "ServerId">;
+export type ProjectId = Brand<string, "ProjectId">;
+export type SessionId = Brand<string, "SessionId">;
+export type TaskId = Brand<string, "TaskId">;
+export type EventId = Brand<string, "EventId">;
+export type ArtifactId = Brand<string, "ArtifactId">;
+export type AuditId = Brand<string, "AuditId">;
+export type CapabilityId = Brand<string, "CapabilityId">;
+
+export type Timestamp = Brand<string, "Timestamp">;
+export type Cursor = Brand<string, "Cursor">;
+
+/** 已知值保留自动补全，同时允许服务端返回未来新增值。 */
+export type ForwardCompatible<Known extends string> = Known | (string & {});
+
+export interface ProtocolVersion extends Extensible {
+  readonly major: number;
+  readonly minor: number;
+  readonly patch: number;
+}
+
+export interface ProtocolEnvelope extends Extensible {
+  readonly protocol_version: ProtocolVersion;
+  readonly request_id?: string;
+}
+
+export interface ServerContext extends Extensible {
+  readonly server_id: ServerId;
+}
+
+export interface ProjectContext extends ServerContext {
+  readonly project_id: ProjectId;
+}
+
+export interface SessionContext extends ProjectContext {
+  readonly session_id: SessionId;
+}
+
+export interface PageRequest extends Extensible {
+  readonly cursor?: Cursor;
+  readonly page_size?: number;
+}
+
+export interface PageInfo extends Extensible {
+  readonly next_cursor?: Cursor;
+  readonly has_more: boolean;
+}
+
+export interface Page<T> extends Extensible {
+  readonly items: readonly T[];
+  readonly page_info: PageInfo;
+}
+
+export type ConnectionState = ForwardCompatible<
+  | "DISCONNECTED" | "CONNECTING" | "TLS_HANDSHAKE" | "AUTHENTICATING"
+  | "NEGOTIATING" | "SYNCHRONIZING" | "CONNECTED" | "DEGRADED"
+  | "RECONNECTING" | "AUTH_EXPIRED" | "FAILED"
+>;
+
+export interface Teamserver extends ServerContext, Extensible {
+  readonly name: string;
+  readonly protocol_version: ProtocolVersion;
+  readonly connection_state: ConnectionState;
+  readonly capabilities: readonly CapabilityId[];
+}
+
+export interface Project extends ProjectContext, Extensible {
+  readonly name: string;
+  readonly description?: string;
+  readonly capabilities: readonly CapabilityId[];
+}
+
+export type SessionState = ForwardCompatible<"ONLINE" | "OFFLINE" | "DORMANT" | "LOST">;
+
+export interface Session extends SessionContext, Extensible {
+  readonly name: string;
+  readonly state: SessionState;
+  readonly hostname?: string;
+  readonly username?: string;
+  readonly os?: string;
+  readonly architecture?: string;
+  readonly first_seen_at: Timestamp;
+  readonly last_active_at: Timestamp;
+  readonly tags: readonly string[];
+  readonly capabilities: readonly CapabilityId[];
+}
+
+export type JsonSchema = Readonly<Record<string, unknown>>;
+
+export interface Capability extends ProjectContext, Extensible {
+  readonly capability_id: CapabilityId;
+  readonly name: string;
+  readonly description?: string;
+  readonly input_schema: JsonSchema;
+  readonly output_schema?: JsonSchema;
+  readonly supports_batch: boolean;
+}
+
+export type TaskState = ForwardCompatible<
+  "PENDING" | "RUNNING" | "SUCCEEDED" | "FAILED" | "CANCELLED"
+>;
+
+export interface Task extends SessionContext, Extensible {
+  readonly task_id: TaskId;
+  readonly capability_id: CapabilityId;
+  readonly state: TaskState;
+  readonly cancellable: boolean;
+  readonly created_at: Timestamp;
+  readonly updated_at: Timestamp;
+  readonly result?: unknown;
+  readonly error?: ProtocolError;
+}
+
+export interface EventContext extends ServerContext, Extensible {
+  readonly project_id?: ProjectId;
+  readonly session_id?: SessionId;
+  readonly task_id?: TaskId;
+}
+
+export interface Event extends Extensible {
+  readonly event_id: EventId;
+  readonly type: ForwardCompatible<"SESSION_UPDATED" | "TASK_UPDATED" | "TASK_OUTPUT" | "ARTIFACT_CREATED">;
+  readonly timestamp: Timestamp;
+  readonly cursor: Cursor;
+  readonly sequence?: number;
+  readonly context: EventContext;
+  readonly payload: unknown;
+}
+
+export interface Artifact extends SessionContext, Extensible {
+  readonly artifact_id: ArtifactId;
+  readonly task_id?: TaskId;
+  readonly name: string;
+  readonly media_type: string;
+  readonly size_bytes: number;
+  readonly sha256?: string;
+  readonly created_at: Timestamp;
+}
+
+export interface AuditRecord extends ProjectContext, Extensible {
+  readonly audit_id: AuditId;
+  readonly actor: string;
+  readonly action: string;
+  readonly target: Readonly<Record<string, string>>;
+  readonly parameter_summary?: Readonly<Record<string, unknown>>;
+  readonly outcome: ForwardCompatible<"SUCCEEDED" | "FAILED" | "DENIED">;
+  readonly request_id: string;
+  readonly timestamp: Timestamp;
+}
+
+export interface ProtocolError extends Extensible {
+  readonly code: ForwardCompatible<
+    "NETWORK" | "TLS" | "AUTHENTICATION" | "INCOMPATIBLE_VERSION" |
+    "PERMISSION_DENIED" | "RATE_LIMITED" | "TIMEOUT" | "INVALID_MESSAGE" | "INTERNAL"
+  >;
+  readonly message: string;
+  readonly retryable: boolean;
+  readonly details?: Readonly<Record<string, unknown>>;
+}
diff --git a/src/protocol/parser.test.ts b/src/protocol/parser.test.ts
new file mode 100644
index 0000000..e7a1701
--- /dev/null
+++ b/src/protocol/parser.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from "vitest";
+import { demoSession } from "./fixtures";
+import { isProtocolVersion, isSession, parseSession, ProtocolParseError } from "./parser";
+
+describe("协议解析", () => {
+  it("接受完整 Session 并保留未知枚举和扩展字段", () => {
+    const futureSession = { ...demoSession, state: "SUSPENDED_BY_POLICY", vendor_status: 42 };
+    const parsed = parseSession(futureSession);
+    expect(parsed.state).toBe("SUSPENDED_BY_POLICY");
+    expect(parsed.vendor_status).toBe(42);
+  });
+
+  it("拒绝缺少 project_id 的跨上下文 Session", () => {
+    const { project_id: _projectId, ...invalid } = demoSession;
+    expect(isSession(invalid)).toBe(false);
+    expect(() => parseSession(invalid)).toThrow(ProtocolParseError);
+  });
+
+  it("协议版本必须由非负整数构成", () => {
+    expect(isProtocolVersion({ major: 1, minor: 0, patch: 0, future: true })).toBe(true);
+    expect(isProtocolVersion({ major: 1, minor: -1, patch: 0 })).toBe(false);
+  });
+});
diff --git a/src/protocol/parser.ts b/src/protocol/parser.ts
new file mode 100644
index 0000000..71f4740
--- /dev/null
+++ b/src/protocol/parser.ts
@@ -0,0 +1,49 @@
+import type { ProjectContext, ProtocolVersion, Session, SessionContext } from "./model";
+
+export class ProtocolParseError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = "ProtocolParseError";
+  }
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null && !Array.isArray(value);
+}
+
+function hasString(value: Record<string, unknown>, key: string): boolean {
+  return typeof value[key] === "string" && value[key] !== "";
+}
+
+export function isProtocolVersion(value: unknown): value is ProtocolVersion {
+  return isRecord(value) && ["major", "minor", "patch"].every(
+    (key) => Number.isInteger(value[key]) && (value[key] as number) >= 0,
+  );
+}
+
+export function isProjectContext(value: unknown): value is ProjectContext {
+  return isRecord(value) && hasString(value, "server_id") && hasString(value, "project_id");
+}
+
+export function isSessionContext(value: unknown): value is SessionContext {
+  return isProjectContext(value) && hasString(value, "session_id");
+}
+
+export function isSession(value: unknown): value is Session {
+  if (!isRecord(value) || !isSessionContext(value)) return false;
+  return hasString(value, "name")
+    && hasString(value, "state")
+    && hasString(value, "first_seen_at")
+    && hasString(value, "last_active_at")
+    && Array.isArray(value.tags)
+    && value.tags.every((tag) => typeof tag === "string")
+    && Array.isArray(value.capabilities)
+    && value.capabilities.every((capability) => typeof capability === "string");
+}
+
+export function parseSession(value: unknown): Session {
+  if (!isSession(value)) {
+    throw new ProtocolParseError("无效的 Session：缺少上下文字段或标准字段类型错误");
+  }
+  return value;
+}