diff --git a/.ai-work/02-extract-shared-dto-event-types.md b/.ai-work/02-extract-shared-dto-event-types.md
index 09cd934..7861936 100644
--- a/.ai-work/02-extract-shared-dto-event-types.md
+++ b/.ai-work/02-extract-shared-dto-event-types.md
@@ -1,5 +1,5 @@
 # 02. Extract shared DTO/event types
 
-Status: pending
+Status: completed
 
 Move duplicated API/session DTO definitions into shared modules used by both client and server.
diff --git a/src/client/src/api.ts b/src/client/src/api.ts
index 77e5e44..bbe01c4 100644
--- a/src/client/src/api.ts
+++ b/src/client/src/api.ts
@@ -1,134 +1,6 @@
-export interface Project {
-  id: string;
-  name: string;
-  path: string;
-  createdAt: string;
-}
+import type { CommandOption, CommandResult, FileContentResponse, FileSuggestion, FileTreeEntry, FileTreeResponse, GitDiffResponse, GitFileState, GitStatusFile, GitStatusResponse, MessagePage, Project, SessionInfo, SessionStatus, SlashCommand, Workspace } from "../../shared/apiTypes";
 
-export interface Workspace {
-  id: string;
-  projectId: string;
-  path: string;
-  label: string;
-  branch?: string;
-  isMain: boolean;
-  isGitWorktree: boolean;
-}
-
-export interface SessionInfo {
-  id: string;
-  path: string;
-  cwd: string;
-  name?: string;
-  created: string;
-  modified: string;
-  messageCount: number;
-  firstMessage: string;
-  archived?: boolean;
-  archivedAt?: string;
-}
-
-export interface SessionActivity {
-  sessionId: string;
-  phase: "active" | "idle" | "error";
-  label: string;
-  detail?: string;
-  at: string;
-}
-
-export interface SessionStatus {
-  sessionId: string;
-  model?: { provider?: string; id?: string; name?: string; contextWindow?: number; reasoning?: unknown };
-  thinkingLevel?: string;
-  isStreaming: boolean;
-  isCompacting: boolean;
-  isBashRunning: boolean;
-  pendingMessageCount: number;
-  tokens: { input: number; output: number; cacheRead: number; cacheWrite: number; total: number };
-  cost: number;
-  contextUsage?: { tokens: number | null; contextWindow: number; percent: number | null };
-}
-
-export interface SlashCommand {
-  name: string;
-  description?: string;
-  source: "extension" | "prompt" | "skill" | "builtin";
-}
-
-export interface FileSuggestion {
-  path: string;
-  kind: "tracked" | "untracked" | "other";
-}
-
-export interface FileTreeEntry {
-  name: string;
-  path: string;
-  type: "file" | "directory" | "symlink";
-  size?: number;
-  modifiedAt?: string;
-}
-
-export interface FileTreeResponse {
-  path: string;
-  entries: FileTreeEntry[];
-  scannedAt: string;
-  truncated: boolean;
-}
-
-export interface FileContentResponse {
-  path: string;
-  language?: string;
-  encoding: "utf8";
-  size: number;
-  modifiedAt: string;
-  content: string;
-  truncated: boolean;
-  binary: boolean;
-}
-
-export type GitFileState = "unmodified" | "modified" | "added" | "deleted" | "renamed" | "copied" | "untracked" | "ignored" | "conflicted";
-
-export interface GitStatusFile {
-  path: string;
-  oldPath?: string;
-  index: GitFileState;
-  workingTree: GitFileState;
-}
-
-export interface GitStatusResponse {
-  isGitRepo: boolean;
-  hash: string;
-  branch?: string;
-  upstream?: string;
-  ahead?: number;
-  behind?: number;
-  files: GitStatusFile[];
-}
-
-export interface GitDiffResponse {
-  path?: string;
-  staged: boolean;
-  hash: string;
-  diff: string;
-  truncated: boolean;
-}
-
-export interface CommandOption {
-  value: string;
-  label: string;
-  description?: string;
-}
-
-export interface MessagePage {
-  messages: unknown[];
-  start: number;
-  total: number;
-}
-
-export type CommandResult =
-  | { type: "done"; message?: string; session?: SessionInfo }
-  | { type: "select"; requestId: string; title: string; options: CommandOption[] }
-  | { type: "unsupported"; message: string };
+export type { CommandOption, CommandResult, FileContentResponse, FileSuggestion, FileTreeEntry, FileTreeResponse, GitDiffResponse, GitFileState, GitStatusFile, GitStatusResponse, MessagePage, Project, SessionActivity, SessionInfo, SessionStatus, SlashCommand, SessionUiEvent, Workspace } from "../../shared/apiTypes";
 
 async function request<T>(url: string, parse: (value: unknown) => T, init?: RequestInit): Promise<T> {
   const headers = new Headers(init?.headers);
diff --git a/src/client/src/sessionSocket.ts b/src/client/src/sessionSocket.ts
index 016667f..d378dc4 100644
--- a/src/client/src/sessionSocket.ts
+++ b/src/client/src/sessionSocket.ts
@@ -1,16 +1,7 @@
-import { globalSessionEvents, sessionEvents, type SessionActivity, type SessionStatus } from "./api";
+import { globalSessionEvents, sessionEvents } from "./api";
+import type { SessionUiEvent } from "../../shared/apiTypes";
 
-export type SessionUiEvent =
-  | { type: "assistant.delta"; text: string }
-  | { type: "tool.start"; toolName: string; summary: string; args?: unknown }
-  | { type: "tool.end"; toolName: string; text: string; isError: boolean; content?: unknown }
-  | { type: "shell.start"; command: string; excludeFromContext?: boolean }
-  | { type: "shell.chunk"; chunk: string }
-  | { type: "shell.end"; output?: string; exitCode?: number | null; cancelled?: boolean; truncated?: boolean; fullOutputPath?: string; isError?: boolean }
-  | { type: "status.update"; status: SessionStatus }
-  | { type: "activity.update"; activity: SessionActivity }
-  | { type: "command.output"; level: "info" | "success" | "error"; message: string }
-  | { type: "session.error"; message: string };
+export type { SessionUiEvent } from "../../shared/apiTypes";
 
 export class SessionSocket {
   private socket: WebSocket | undefined;
diff --git a/src/server/git/gitService.ts b/src/server/git/gitService.ts
index 734c119..ba864a8 100644
--- a/src/server/git/gitService.ts
+++ b/src/server/git/gitService.ts
@@ -1,34 +1,8 @@
 import { createHash } from "node:crypto";
 import { spawn } from "node:child_process";
+import type { GitDiffResponse, GitFileState, GitStatusFile, GitStatusResponse } from "../../shared/apiTypes.js";
 import { normalizeRelativePath } from "../workspaces/pathSafety.js";
 
-export type GitFileState = "unmodified" | "modified" | "added" | "deleted" | "renamed" | "copied" | "untracked" | "ignored" | "conflicted";
-
-export interface GitStatusFile {
-  path: string;
-  oldPath?: string;
-  index: GitFileState;
-  workingTree: GitFileState;
-}
-
-export interface GitStatusResponse {
-  isGitRepo: boolean;
-  hash: string;
-  branch?: string;
-  upstream?: string;
-  ahead?: number;
-  behind?: number;
-  files: GitStatusFile[];
-}
-
-export interface GitDiffResponse {
-  path?: string;
-  staged: boolean;
-  hash: string;
-  diff: string;
-  truncated: boolean;
-}
-
 const MAX_OUTPUT = 2 * 1024 * 1024;
 
 export async function gitStatus(cwd: string): Promise<GitStatusResponse> {
diff --git a/src/server/types.ts b/src/server/types.ts
index e0ab9e4..1bb2024 100644
--- a/src/server/types.ts
+++ b/src/server/types.ts
@@ -1,70 +1,13 @@
-export interface Project {
-  id: string;
-  name: string;
-  path: string;
-  createdAt: string;
-}
-
-export interface Workspace {
-  id: string;
-  projectId: string;
-  path: string;
-  label: string;
-  branch?: string;
-  isMain: boolean;
-  isGitWorktree: boolean;
-}
-
-export interface ClientSession {
-  id: string;
-  path: string;
-  cwd: string;
-  name?: string;
-  created: string;
-  modified: string;
-  messageCount: number;
-  firstMessage: string;
-  archived?: boolean;
-  archivedAt?: string;
-}
-
-export interface ClientMessagePage {
-  messages: unknown[];
-  start: number;
-  total: number;
-}
-
-export interface ClientSessionStatus {
-  sessionId: string;
-  model?: { provider?: string; id?: string; name?: string; contextWindow?: number; reasoning?: unknown };
-  thinkingLevel?: string;
-  isStreaming: boolean;
-  isCompacting: boolean;
-  isBashRunning: boolean;
-  pendingMessageCount: number;
-  tokens: { input: number; output: number; cacheRead: number; cacheWrite: number; total: number };
-  cost: number;
-  contextUsage?: { tokens: number | null; contextWindow: number; percent: number | null };
-}
-
-export interface ClientCommand {
-  name: string;
-  description?: string;
-  source: "extension" | "prompt" | "skill" | "builtin";
-}
-
-export interface ClientFileSuggestion {
-  path: string;
-  kind: "tracked" | "untracked" | "other";
-}
-
-export interface ClientCommandOption {
-  value: string;
-  label: string;
-  description?: string;
-}
-
-export type ClientCommandResult =
-  | { type: "done"; message?: string; session?: ClientSession }
-  | { type: "select"; requestId: string; title: string; options: ClientCommandOption[] }
-  | { type: "unsupported"; message: string };
+export type {
+  Project,
+  Workspace,
+  SessionInfo as ClientSession,
+  MessagePage as ClientMessagePage,
+  SessionStatus as ClientSessionStatus,
+  SlashCommand as ClientCommand,
+  FileSuggestion as ClientFileSuggestion,
+  CommandOption as ClientCommandOption,
+  CommandResult as ClientCommandResult,
+  SessionActivity as ClientSessionActivity,
+  SessionUiEvent,
+} from "../shared/apiTypes.js";
diff --git a/src/server/workspaces/fileContentService.ts b/src/server/workspaces/fileContentService.ts
index 983c696..96ff86f 100644
--- a/src/server/workspaces/fileContentService.ts
+++ b/src/server/workspaces/fileContentService.ts
@@ -1,17 +1,7 @@
 import { readFile, stat } from "node:fs/promises";
+import type { FileContentResponse } from "../../shared/apiTypes.js";
 import { resolveInsideWorkspace } from "./pathSafety.js";
 
-export interface FileContentResponse {
-  path: string;
-  language?: string;
-  encoding: "utf8";
-  size: number;
-  modifiedAt: string;
-  content: string;
-  truncated: boolean;
-  binary: boolean;
-}
-
 const MAX_BYTES = 512 * 1024;
 
 export async function readWorkspaceFile(rootPath: string, path: string | undefined): Promise<FileContentResponse> {
diff --git a/src/server/workspaces/fileTreeService.ts b/src/server/workspaces/fileTreeService.ts
index b12cbe5..6e62bde 100644
--- a/src/server/workspaces/fileTreeService.ts
+++ b/src/server/workspaces/fileTreeService.ts
@@ -1,22 +1,8 @@
 import { lstat, readdir } from "node:fs/promises";
 import { join } from "node:path";
+import type { FileTreeEntry, FileTreeResponse } from "../../shared/apiTypes.js";
 import { resolveInsideWorkspace } from "./pathSafety.js";
 
-export interface FileTreeEntry {
-  name: string;
-  path: string;
-  type: "file" | "directory" | "symlink";
-  size?: number;
-  modifiedAt?: string;
-}
-
-export interface FileTreeResponse {
-  path: string;
-  entries: FileTreeEntry[];
-  scannedAt: string;
-  truncated: boolean;
-}
-
 const MAX_ENTRIES = 1000;
 
 export async function listWorkspaceTree(rootPath: string, path: string | undefined): Promise<FileTreeResponse> {
diff --git a/src/shared/apiTypes.ts b/src/shared/apiTypes.ts
new file mode 100644
index 0000000..fb2b77c
--- /dev/null
+++ b/src/shared/apiTypes.ts
@@ -0,0 +1,143 @@
+export interface Project {
+  id: string;
+  name: string;
+  path: string;
+  createdAt: string;
+}
+
+export interface Workspace {
+  id: string;
+  projectId: string;
+  path: string;
+  label: string;
+  branch?: string;
+  isMain: boolean;
+  isGitWorktree: boolean;
+}
+
+export interface SessionInfo {
+  id: string;
+  path: string;
+  cwd: string;
+  name?: string;
+  created: string;
+  modified: string;
+  messageCount: number;
+  firstMessage: string;
+  archived?: boolean;
+  archivedAt?: string;
+}
+
+export interface SessionActivity {
+  sessionId: string;
+  phase: "active" | "idle" | "error";
+  label: string;
+  detail?: string;
+  at: string;
+}
+
+export interface SessionStatus {
+  sessionId: string;
+  model?: { provider?: string; id?: string; name?: string; contextWindow?: number; reasoning?: unknown };
+  thinkingLevel?: string;
+  isStreaming: boolean;
+  isCompacting: boolean;
+  isBashRunning: boolean;
+  pendingMessageCount: number;
+  tokens: { input: number; output: number; cacheRead: number; cacheWrite: number; total: number };
+  cost: number;
+  contextUsage?: { tokens: number | null; contextWindow: number; percent: number | null };
+}
+
+export interface SlashCommand {
+  name: string;
+  description?: string;
+  source: "extension" | "prompt" | "skill" | "builtin";
+}
+
+export interface FileSuggestion {
+  path: string;
+  kind: "tracked" | "untracked" | "other";
+}
+
+export interface FileTreeEntry {
+  name: string;
+  path: string;
+  type: "file" | "directory" | "symlink";
+  size?: number;
+  modifiedAt?: string;
+}
+
+export interface FileTreeResponse {
+  path: string;
+  entries: FileTreeEntry[];
+  scannedAt: string;
+  truncated: boolean;
+}
+
+export interface FileContentResponse {
+  path: string;
+  language?: string;
+  encoding: "utf8";
+  size: number;
+  modifiedAt: string;
+  content: string;
+  truncated: boolean;
+  binary: boolean;
+}
+
+export type GitFileState = "unmodified" | "modified" | "added" | "deleted" | "renamed" | "copied" | "untracked" | "ignored" | "conflicted";
+
+export interface GitStatusFile {
+  path: string;
+  oldPath?: string;
+  index: GitFileState;
+  workingTree: GitFileState;
+}
+
+export interface GitStatusResponse {
+  isGitRepo: boolean;
+  hash: string;
+  branch?: string;
+  upstream?: string;
+  ahead?: number;
+  behind?: number;
+  files: GitStatusFile[];
+}
+
+export interface GitDiffResponse {
+  path?: string;
+  staged: boolean;
+  hash: string;
+  diff: string;
+  truncated: boolean;
+}
+
+export interface CommandOption {
+  value: string;
+  label: string;
+  description?: string;
+}
+
+export interface MessagePage {
+  messages: unknown[];
+  start: number;
+  total: number;
+}
+
+export type CommandResult =
+  | { type: "done"; message?: string; session?: SessionInfo }
+  | { type: "select"; requestId: string; title: string; options: CommandOption[] }
+  | { type: "unsupported"; message: string };
+
+export type SessionUiEvent =
+  | { type: "assistant.delta"; text: string }
+  | { type: "tool.start"; toolName: string; summary: string; args?: unknown }
+  | { type: "tool.end"; toolName: string; text: string; isError: boolean; content?: unknown }
+  | { type: "shell.start"; command: string; excludeFromContext?: boolean }
+  | { type: "shell.chunk"; chunk: string }
+  | { type: "shell.end"; output?: string; exitCode?: number | null; cancelled?: boolean; truncated?: boolean; fullOutputPath?: string; isError?: boolean }
+  | { type: "status.update"; status: SessionStatus }
+  | { type: "activity.update"; activity: SessionActivity }
+  | { type: "command.output"; level: "info" | "success" | "error"; message: string }
+  | { type: "session.error"; message: string };