diff --git a/.ai-work/03-split-client-api.md b/.ai-work/03-split-client-api.md
index a1fe8fc..18cab13 100644
--- a/.ai-work/03-split-client-api.md
+++ b/.ai-work/03-split-client-api.md
@@ -1,5 +1,5 @@
 # 03. Split client API into feature clients
 
-Status: pending
+Status: completed
 
 Decompose `src/client/src/api.ts` into composable feature clients, shared HTTP helper, parsers, URL builders, and socket helpers.
diff --git a/src/client/src/api.ts b/src/client/src/api.ts
index bbe01c4..031927f 100644
--- a/src/client/src/api.ts
+++ b/src/client/src/api.ts
@@ -1,332 +1,3 @@
-import type { CommandOption, CommandResult, FileContentResponse, FileSuggestion, FileTreeEntry, FileTreeResponse, GitDiffResponse, GitFileState, GitStatusFile, GitStatusResponse, MessagePage, Project, SessionInfo, SessionStatus, SlashCommand, Workspace } from "../../shared/apiTypes";
-
+export { api, filesApi, gitApi, projectsApi, sessionsApi, workspacesApi } from "./api/clients";
+export { globalSessionEvents, sessionEvents } from "./api/sockets";
 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);
-  if (init?.body !== undefined) headers.set("content-type", "application/json");
-  const response = await fetch(url, { ...init, headers });
-  if (!response.ok) {
-    const body: unknown = await response.json().catch((): unknown => ({}));
-    throw new Error(errorMessage(body) ?? response.statusText);
-  }
-  const body: unknown = await response.json();
-  return parse(body);
-}
-
-function errorMessage(value: unknown): string | undefined {
-  if (!isRecord(value)) return undefined;
-  return typeof value["error"] === "string" ? value["error"] : undefined;
-}
-
-export const api = {
-  projects: () => request("/api/projects", arrayOf(parseProject)),
-  addProject: (path: string, name?: string) => request("/api/projects", parseProject, { method: "POST", body: JSON.stringify({ path, name }) }),
-  workspaces: (projectId: string) => request(`/api/projects/${projectId}/workspaces`, arrayOf(parseWorkspace)),
-  sessions: (cwd: string) => request(`/api/sessions?cwd=${encodeURIComponent(cwd)}`, arrayOf(parseSessionInfo)),
-  startSession: (cwd: string) => request("/api/sessions", parseSessionInfo, { method: "POST", body: JSON.stringify({ cwd }) }),
-  messages: (sessionId: string, options?: { limit?: number; before?: number }) => request(messageUrl(sessionId, options), parseMessagePage),
-  status: (sessionId: string) => request(`/api/sessions/${sessionId}/status`, parseSessionStatus),
-  commands: (sessionId: string) => request(`/api/sessions/${sessionId}/commands`, arrayOf(parseSlashCommand)),
-  files: (cwd: string, query: string, kind?: FileSuggestion["kind"], mode?: "file" | "path") => request(`/api/files?cwd=${encodeURIComponent(cwd)}&q=${encodeURIComponent(query)}${kind !== undefined ? `&kind=${encodeURIComponent(kind)}` : ""}${mode !== undefined ? `&mode=${encodeURIComponent(mode)}` : ""}`, arrayOf(parseFileSuggestion)),
-  workspaceTree: (projectId: string, workspaceId: string, path = "") => request(`/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/tree?path=${encodeURIComponent(path)}`, parseFileTreeResponse),
-  workspaceFile: (projectId: string, workspaceId: string, path: string) => request(`/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/file?path=${encodeURIComponent(path)}`, parseFileContentResponse),
-  gitStatus: (projectId: string, workspaceId: string) => request(`/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/git/status`, parseGitStatusResponse),
-  gitDiff: (projectId: string, workspaceId: string, options?: { path?: string; staged?: boolean }) => request(gitDiffUrl(projectId, workspaceId, options), parseGitDiffResponse),
-  prompt: (sessionId: string, text: string, streamingBehavior?: "steer" | "followUp") => request(`/api/sessions/${sessionId}/prompt`, parseAccepted, { method: "POST", body: JSON.stringify(streamingBehavior === undefined ? { text } : { text, streamingBehavior }) }),
-  shell: (sessionId: string, text: string) => request(`/api/sessions/${sessionId}/shell`, parseAccepted, { method: "POST", body: JSON.stringify({ text }) }),
-  runCommand: (sessionId: string, text: string) => request(`/api/sessions/${sessionId}/commands/run`, parseCommandResult, { method: "POST", body: JSON.stringify({ text }) }),
-  respondToCommand: (sessionId: string, requestId: string, value: string) => request(`/api/sessions/${sessionId}/commands/respond`, parseCommandResult, { method: "POST", body: JSON.stringify({ requestId, value }) }),
-  abort: (sessionId: string) => request(`/api/sessions/${sessionId}/abort`, parseAborted, { method: "POST" }),
-  stop: (sessionId: string) => request(`/api/sessions/${sessionId}/stop`, parseStopped, { method: "POST" }),
-  archive: (sessionId: string) => request(`/api/sessions/${sessionId}/archive`, parseArchived, { method: "POST" }),
-  restore: (sessionId: string) => request(`/api/sessions/${sessionId}/restore`, parseRestored, { method: "POST" }),
-};
-
-export function sessionEvents(sessionId: string): WebSocket {
-  return new WebSocket(`${webSocketBaseUrl()}/api/sessions/${sessionId}/events`);
-}
-
-export function globalSessionEvents(): WebSocket {
-  return new WebSocket(`${webSocketBaseUrl()}/api/sessions/events`);
-}
-
-function gitDiffUrl(projectId: string, workspaceId: string, options?: { path?: string; staged?: boolean }): string {
-  const params = new URLSearchParams();
-  if (options?.path !== undefined) params.set("path", options.path);
-  if (options?.staged === true) params.set("staged", "true");
-  const query = params.toString();
-  return `/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/git/diff${query ? `?${query}` : ""}`;
-}
-
-function messageUrl(sessionId: string, options?: { limit?: number; before?: number }): string {
-  const params = new URLSearchParams();
-  if (options?.limit !== undefined) params.set("limit", String(options.limit));
-  if (options?.before !== undefined) params.set("before", String(options.before));
-  const query = params.toString();
-  return `/api/sessions/${sessionId}/messages${query ? `?${query}` : ""}`;
-}
-
-function webSocketBaseUrl(): string {
-  const protocol = location.protocol === "https:" ? "wss:" : "ws:";
-  return `${protocol}//${location.host}`;
-}
-
-function isRecord(value: unknown): value is Record<string, unknown> {
-  return typeof value === "object" && value !== null;
-}
-
-function requireRecord(value: unknown): Record<string, unknown> {
-  if (!isRecord(value)) throw new Error("Expected object response");
-  return value;
-}
-
-function requireString(record: Record<string, unknown>, key: string): string {
-  const value = record[key];
-  if (typeof value !== "string") throw new Error(`Expected string field: ${key}`);
-  return value;
-}
-
-function optionalString(record: Record<string, unknown>, key: string): string | undefined {
-  const value = record[key];
-  if (value === undefined) return undefined;
-  if (typeof value !== "string") throw new Error(`Expected optional string field: ${key}`);
-  return value;
-}
-
-function requireNumber(record: Record<string, unknown>, key: string): number {
-  const value = record[key];
-  if (typeof value !== "number") throw new Error(`Expected number field: ${key}`);
-  return value;
-}
-
-function requireBoolean(record: Record<string, unknown>, key: string): boolean {
-  const value = record[key];
-  if (typeof value !== "boolean") throw new Error(`Expected boolean field: ${key}`);
-  return value;
-}
-
-function arrayOf<T>(parse: (value: unknown) => T): (value: unknown) => T[] {
-  return (value) => {
-    if (!Array.isArray(value)) throw new Error("Expected array response");
-    return value.map(parse);
-  };
-}
-
-function parseUnknownArray(value: unknown): unknown[] {
-  if (!Array.isArray(value)) throw new Error("Expected array response");
-  return value;
-}
-
-function parseMessagePage(value: unknown): MessagePage {
-  if (Array.isArray(value)) return { messages: value, start: 0, total: value.length };
-  const record = requireRecord(value);
-  return { messages: parseUnknownArray(record["messages"]), start: requireNumber(record, "start"), total: requireNumber(record, "total") };
-}
-
-function parseProject(value: unknown): Project {
-  const record = requireRecord(value);
-  return { id: requireString(record, "id"), name: requireString(record, "name"), path: requireString(record, "path"), createdAt: requireString(record, "createdAt") };
-}
-
-function parseWorkspace(value: unknown): Workspace {
-  const record = requireRecord(value);
-  const branch = optionalString(record, "branch");
-  return {
-    id: requireString(record, "id"),
-    projectId: requireString(record, "projectId"),
-    path: requireString(record, "path"),
-    label: requireString(record, "label"),
-    ...(branch === undefined ? {} : { branch }),
-    isMain: requireBoolean(record, "isMain"),
-    isGitWorktree: requireBoolean(record, "isGitWorktree"),
-  };
-}
-
-function parseSessionInfo(value: unknown): SessionInfo {
-  const record = requireRecord(value);
-  const name = optionalString(record, "name");
-  const archivedAt = optionalString(record, "archivedAt");
-  return {
-    id: requireString(record, "id"),
-    path: requireString(record, "path"),
-    cwd: requireString(record, "cwd"),
-    ...(name === undefined ? {} : { name }),
-    created: requireString(record, "created"),
-    modified: requireString(record, "modified"),
-    messageCount: requireNumber(record, "messageCount"),
-    firstMessage: requireString(record, "firstMessage"),
-    ...(record["archived"] === true ? { archived: true } : {}),
-    ...(archivedAt === undefined ? {} : { archivedAt }),
-  };
-}
-
-function parseSessionStatus(value: unknown): SessionStatus {
-  const record = requireRecord(value);
-  return {
-    sessionId: requireString(record, "sessionId"),
-    isStreaming: requireBoolean(record, "isStreaming"),
-    isCompacting: requireBoolean(record, "isCompacting"),
-    isBashRunning: requireBoolean(record, "isBashRunning"),
-    pendingMessageCount: requireNumber(record, "pendingMessageCount"),
-    tokens: parseTokens(record["tokens"]),
-    cost: requireNumber(record, "cost"),
-    ...optionalModel(record["model"]),
-    ...optionalContextUsage(record["contextUsage"]),
-    ...optionalField("thinkingLevel", optionalString(record, "thinkingLevel")),
-  };
-}
-
-function parseTokens(value: unknown): SessionStatus["tokens"] {
-  const record = requireRecord(value);
-  return {
-    input: requireNumber(record, "input"),
-    output: requireNumber(record, "output"),
-    cacheRead: requireNumber(record, "cacheRead"),
-    cacheWrite: requireNumber(record, "cacheWrite"),
-    total: requireNumber(record, "total"),
-  };
-}
-
-function optionalModel(value: unknown): Pick<SessionStatus, "model"> | object {
-  if (value === undefined) return {};
-  const record = requireRecord(value);
-  return { model: { ...optionalField("provider", optionalString(record, "provider")), ...optionalField("id", optionalString(record, "id")), ...optionalField("name", optionalString(record, "name")), ...optionalField("contextWindow", optionalNumber(record, "contextWindow")), ...optionalField("reasoning", record["reasoning"]) } };
-}
-
-function optionalContextUsage(value: unknown): Pick<SessionStatus, "contextUsage"> | object {
-  if (value === undefined) return {};
-  const record = requireRecord(value);
-  return { contextUsage: { tokens: numberOrNull(record, "tokens"), contextWindow: requireNumber(record, "contextWindow"), percent: numberOrNull(record, "percent") } };
-}
-
-function parseSlashCommand(value: unknown): SlashCommand {
-  const record = requireRecord(value);
-  const source = requireString(record, "source");
-  if (source !== "extension" && source !== "prompt" && source !== "skill" && source !== "builtin") throw new Error("Invalid command source");
-  return { name: requireString(record, "name"), source, ...optionalField("description", optionalString(record, "description")) };
-}
-
-function parseFileSuggestion(value: unknown): FileSuggestion {
-  const record = requireRecord(value);
-  const kind = requireString(record, "kind");
-  if (kind !== "tracked" && kind !== "untracked" && kind !== "other") throw new Error("Invalid file kind");
-  return { path: requireString(record, "path"), kind };
-}
-
-function parseFileTreeResponse(value: unknown): FileTreeResponse {
-  const record = requireRecord(value);
-  return { path: requireString(record, "path"), entries: arrayOf(parseFileTreeEntry)(record["entries"]), scannedAt: requireString(record, "scannedAt"), truncated: requireBoolean(record, "truncated") };
-}
-
-function parseFileTreeEntry(value: unknown): FileTreeEntry {
-  const record = requireRecord(value);
-  const type = requireString(record, "type");
-  if (type !== "file" && type !== "directory" && type !== "symlink") throw new Error("Invalid file tree entry type");
-  return { name: requireString(record, "name"), path: requireString(record, "path"), type, ...optionalField("size", optionalNumber(record, "size")), ...optionalField("modifiedAt", optionalString(record, "modifiedAt")) };
-}
-
-function parseFileContentResponse(value: unknown): FileContentResponse {
-  const record = requireRecord(value);
-  const encoding = requireString(record, "encoding");
-  if (encoding !== "utf8") throw new Error("Invalid file encoding");
-  return { path: requireString(record, "path"), ...optionalField("language", optionalString(record, "language")), encoding, size: requireNumber(record, "size"), modifiedAt: requireString(record, "modifiedAt"), content: requireString(record, "content"), truncated: requireBoolean(record, "truncated"), binary: requireBoolean(record, "binary") };
-}
-
-function parseGitStatusResponse(value: unknown): GitStatusResponse {
-  const record = requireRecord(value);
-  return { isGitRepo: requireBoolean(record, "isGitRepo"), hash: requireString(record, "hash"), ...optionalField("branch", optionalString(record, "branch")), ...optionalField("upstream", optionalString(record, "upstream")), ...optionalField("ahead", optionalNumber(record, "ahead")), ...optionalField("behind", optionalNumber(record, "behind")), files: arrayOf(parseGitStatusFile)(record["files"]) };
-}
-
-function parseGitStatusFile(value: unknown): GitStatusFile {
-  const record = requireRecord(value);
-  return { path: requireString(record, "path"), ...optionalField("oldPath", optionalString(record, "oldPath")), index: parseGitFileState(record["index"]), workingTree: parseGitFileState(record["workingTree"]) };
-}
-
-function parseGitFileState(value: unknown): GitFileState {
-  switch (value) {
-    case "unmodified":
-    case "modified":
-    case "added":
-    case "deleted":
-    case "renamed":
-    case "copied":
-    case "untracked":
-    case "ignored":
-    case "conflicted":
-      return value;
-    default:
-      throw new Error("Invalid git file state");
-  }
-}
-
-function parseGitDiffResponse(value: unknown): GitDiffResponse {
-  const record = requireRecord(value);
-  return { ...optionalField("path", optionalString(record, "path")), staged: requireBoolean(record, "staged"), hash: requireString(record, "hash"), diff: requireString(record, "diff"), truncated: requireBoolean(record, "truncated") };
-}
-
-function parseCommandResult(value: unknown): CommandResult {
-  const record = requireRecord(value);
-  const type = requireString(record, "type");
-  if (type === "unsupported") return { type, message: requireString(record, "message") };
-  if (type === "select") return { type, requestId: requireString(record, "requestId"), title: requireString(record, "title"), options: arrayOf(parseCommandOption)(record["options"]) };
-  if (type === "done") return { type, ...optionalField("message", optionalString(record, "message")), ...optionalSession(record["session"]) };
-  throw new Error("Invalid command result type");
-}
-
-function parseCommandOption(value: unknown): CommandOption {
-  const record = requireRecord(value);
-  return { value: requireString(record, "value"), label: requireString(record, "label"), ...optionalField("description", optionalString(record, "description")) };
-}
-
-function optionalSession(value: unknown): Pick<Extract<CommandResult, { type: "done" }>, "session"> | object {
-  return value === undefined ? {} : { session: parseSessionInfo(value) };
-}
-
-function parseAccepted(value: unknown): { accepted: true } {
-  const record = requireRecord(value);
-  if (record["accepted"] !== true) throw new Error("Expected accepted response");
-  return { accepted: true };
-}
-
-function parseAborted(value: unknown): { aborted: true } {
-  const record = requireRecord(value);
-  if (record["aborted"] !== true) throw new Error("Expected aborted response");
-  return { aborted: true };
-}
-
-function parseStopped(value: unknown): { stopped: true } {
-  const record = requireRecord(value);
-  if (record["stopped"] !== true) throw new Error("Expected stopped response");
-  return { stopped: true };
-}
-
-function parseArchived(value: unknown): { archived: true } {
-  const record = requireRecord(value);
-  if (record["archived"] !== true) throw new Error("Expected archived response");
-  return { archived: true };
-}
-
-function parseRestored(value: unknown): { restored: true } {
-  const record = requireRecord(value);
-  if (record["restored"] !== true) throw new Error("Expected restored response");
-  return { restored: true };
-}
-
-function optionalNumber(record: Record<string, unknown>, key: string): number | undefined {
-  const value = record[key];
-  if (value === undefined) return undefined;
-  if (typeof value !== "number") throw new Error(`Expected optional number field: ${key}`);
-  return value;
-}
-
-function numberOrNull(record: Record<string, unknown>, key: string): number | null {
-  const value = record[key];
-  if (value === null) return null;
-  if (typeof value !== "number") throw new Error(`Expected number|null field: ${key}`);
-  return value;
-}
-
-function optionalField(key: string, value: unknown): object {
-  return value === undefined ? {} : { [key]: value };
-}
diff --git a/src/client/src/api/clients.ts b/src/client/src/api/clients.ts
new file mode 100644
index 0000000..3a6b3a6
--- /dev/null
+++ b/src/client/src/api/clients.ts
@@ -0,0 +1,67 @@
+import type { FileSuggestion } from "../../../shared/apiTypes";
+import { request } from "./http";
+import {
+  arrayOf,
+  parseAborted,
+  parseAccepted,
+  parseArchived,
+  parseCommandResult,
+  parseFileContentResponse,
+  parseFileSuggestion,
+  parseFileTreeResponse,
+  parseGitDiffResponse,
+  parseGitStatusResponse,
+  parseMessagePage,
+  parseProject,
+  parseRestored,
+  parseSessionInfo,
+  parseSessionStatus,
+  parseSlashCommand,
+  parseStopped,
+  parseWorkspace,
+} from "./parsers";
+import { gitDiffUrl, messageUrl } from "./urls";
+
+export const projectsApi = {
+  projects: () => request("/api/projects", arrayOf(parseProject)),
+  addProject: (path: string, name?: string) => request("/api/projects", parseProject, { method: "POST", body: JSON.stringify({ path, name }) }),
+};
+
+export const workspacesApi = {
+  workspaces: (projectId: string) => request(`/api/projects/${projectId}/workspaces`, arrayOf(parseWorkspace)),
+  workspaceTree: (projectId: string, workspaceId: string, path = "") => request(`/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/tree?path=${encodeURIComponent(path)}`, parseFileTreeResponse),
+  workspaceFile: (projectId: string, workspaceId: string, path: string) => request(`/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/file?path=${encodeURIComponent(path)}`, parseFileContentResponse),
+};
+
+export const sessionsApi = {
+  sessions: (cwd: string) => request(`/api/sessions?cwd=${encodeURIComponent(cwd)}`, arrayOf(parseSessionInfo)),
+  startSession: (cwd: string) => request("/api/sessions", parseSessionInfo, { method: "POST", body: JSON.stringify({ cwd }) }),
+  messages: (sessionId: string, options?: { limit?: number; before?: number }) => request(messageUrl(sessionId, options), parseMessagePage),
+  status: (sessionId: string) => request(`/api/sessions/${sessionId}/status`, parseSessionStatus),
+  commands: (sessionId: string) => request(`/api/sessions/${sessionId}/commands`, arrayOf(parseSlashCommand)),
+  prompt: (sessionId: string, text: string, streamingBehavior?: "steer" | "followUp") => request(`/api/sessions/${sessionId}/prompt`, parseAccepted, { method: "POST", body: JSON.stringify(streamingBehavior === undefined ? { text } : { text, streamingBehavior }) }),
+  shell: (sessionId: string, text: string) => request(`/api/sessions/${sessionId}/shell`, parseAccepted, { method: "POST", body: JSON.stringify({ text }) }),
+  runCommand: (sessionId: string, text: string) => request(`/api/sessions/${sessionId}/commands/run`, parseCommandResult, { method: "POST", body: JSON.stringify({ text }) }),
+  respondToCommand: (sessionId: string, requestId: string, value: string) => request(`/api/sessions/${sessionId}/commands/respond`, parseCommandResult, { method: "POST", body: JSON.stringify({ requestId, value }) }),
+  abort: (sessionId: string) => request(`/api/sessions/${sessionId}/abort`, parseAborted, { method: "POST" }),
+  stop: (sessionId: string) => request(`/api/sessions/${sessionId}/stop`, parseStopped, { method: "POST" }),
+  archive: (sessionId: string) => request(`/api/sessions/${sessionId}/archive`, parseArchived, { method: "POST" }),
+  restore: (sessionId: string) => request(`/api/sessions/${sessionId}/restore`, parseRestored, { method: "POST" }),
+};
+
+export const filesApi = {
+  files: (cwd: string, query: string, kind?: FileSuggestion["kind"], mode?: "file" | "path") => request(`/api/files?cwd=${encodeURIComponent(cwd)}&q=${encodeURIComponent(query)}${kind !== undefined ? `&kind=${encodeURIComponent(kind)}` : ""}${mode !== undefined ? `&mode=${encodeURIComponent(mode)}` : ""}`, arrayOf(parseFileSuggestion)),
+};
+
+export const gitApi = {
+  gitStatus: (projectId: string, workspaceId: string) => request(`/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/git/status`, parseGitStatusResponse),
+  gitDiff: (projectId: string, workspaceId: string, options?: { path?: string; staged?: boolean }) => request(gitDiffUrl(projectId, workspaceId, options), parseGitDiffResponse),
+};
+
+export const api = {
+  ...projectsApi,
+  ...workspacesApi,
+  ...sessionsApi,
+  ...filesApi,
+  ...gitApi,
+};
diff --git a/src/client/src/api/http.ts b/src/client/src/api/http.ts
new file mode 100644
index 0000000..f1c0da9
--- /dev/null
+++ b/src/client/src/api/http.ts
@@ -0,0 +1,20 @@
+export async function request<T>(url: string, parse: (value: unknown) => T, init?: RequestInit): Promise<T> {
+  const headers = new Headers(init?.headers);
+  if (init?.body !== undefined) headers.set("content-type", "application/json");
+  const response = await fetch(url, { ...init, headers });
+  if (!response.ok) {
+    const body: unknown = await response.json().catch((): unknown => ({}));
+    throw new Error(errorMessage(body) ?? response.statusText);
+  }
+  const body: unknown = await response.json();
+  return parse(body);
+}
+
+function errorMessage(value: unknown): string | undefined {
+  if (!isRecord(value)) return undefined;
+  return typeof value["error"] === "string" ? value["error"] : undefined;
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null;
+}
diff --git a/src/client/src/api/parsers.ts b/src/client/src/api/parsers.ts
new file mode 100644
index 0000000..9bc3220
--- /dev/null
+++ b/src/client/src/api/parsers.ts
@@ -0,0 +1,260 @@
+import type { CommandOption, CommandResult, FileContentResponse, FileSuggestion, FileTreeEntry, FileTreeResponse, GitDiffResponse, GitFileState, GitStatusFile, GitStatusResponse, MessagePage, Project, SessionInfo, SessionStatus, SlashCommand, Workspace } from "../../../shared/apiTypes";
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null;
+}
+
+function requireRecord(value: unknown): Record<string, unknown> {
+  if (!isRecord(value)) throw new Error("Expected object response");
+  return value;
+}
+
+function requireString(record: Record<string, unknown>, key: string): string {
+  const value = record[key];
+  if (typeof value !== "string") throw new Error(`Expected string field: ${key}`);
+  return value;
+}
+
+function optionalString(record: Record<string, unknown>, key: string): string | undefined {
+  const value = record[key];
+  if (value === undefined) return undefined;
+  if (typeof value !== "string") throw new Error(`Expected optional string field: ${key}`);
+  return value;
+}
+
+function requireNumber(record: Record<string, unknown>, key: string): number {
+  const value = record[key];
+  if (typeof value !== "number") throw new Error(`Expected number field: ${key}`);
+  return value;
+}
+
+function requireBoolean(record: Record<string, unknown>, key: string): boolean {
+  const value = record[key];
+  if (typeof value !== "boolean") throw new Error(`Expected boolean field: ${key}`);
+  return value;
+}
+
+export function arrayOf<T>(parse: (value: unknown) => T): (value: unknown) => T[] {
+  return (value) => {
+    if (!Array.isArray(value)) throw new Error("Expected array response");
+    return value.map(parse);
+  };
+}
+
+function parseUnknownArray(value: unknown): unknown[] {
+  if (!Array.isArray(value)) throw new Error("Expected array response");
+  return value;
+}
+
+export function parseMessagePage(value: unknown): MessagePage {
+  if (Array.isArray(value)) return { messages: value, start: 0, total: value.length };
+  const record = requireRecord(value);
+  return { messages: parseUnknownArray(record["messages"]), start: requireNumber(record, "start"), total: requireNumber(record, "total") };
+}
+
+export function parseProject(value: unknown): Project {
+  const record = requireRecord(value);
+  return { id: requireString(record, "id"), name: requireString(record, "name"), path: requireString(record, "path"), createdAt: requireString(record, "createdAt") };
+}
+
+export function parseWorkspace(value: unknown): Workspace {
+  const record = requireRecord(value);
+  const branch = optionalString(record, "branch");
+  return {
+    id: requireString(record, "id"),
+    projectId: requireString(record, "projectId"),
+    path: requireString(record, "path"),
+    label: requireString(record, "label"),
+    ...(branch === undefined ? {} : { branch }),
+    isMain: requireBoolean(record, "isMain"),
+    isGitWorktree: requireBoolean(record, "isGitWorktree"),
+  };
+}
+
+export function parseSessionInfo(value: unknown): SessionInfo {
+  const record = requireRecord(value);
+  const name = optionalString(record, "name");
+  const archivedAt = optionalString(record, "archivedAt");
+  return {
+    id: requireString(record, "id"),
+    path: requireString(record, "path"),
+    cwd: requireString(record, "cwd"),
+    ...(name === undefined ? {} : { name }),
+    created: requireString(record, "created"),
+    modified: requireString(record, "modified"),
+    messageCount: requireNumber(record, "messageCount"),
+    firstMessage: requireString(record, "firstMessage"),
+    ...(record["archived"] === true ? { archived: true } : {}),
+    ...(archivedAt === undefined ? {} : { archivedAt }),
+  };
+}
+
+export function parseSessionStatus(value: unknown): SessionStatus {
+  const record = requireRecord(value);
+  return {
+    sessionId: requireString(record, "sessionId"),
+    isStreaming: requireBoolean(record, "isStreaming"),
+    isCompacting: requireBoolean(record, "isCompacting"),
+    isBashRunning: requireBoolean(record, "isBashRunning"),
+    pendingMessageCount: requireNumber(record, "pendingMessageCount"),
+    tokens: parseTokens(record["tokens"]),
+    cost: requireNumber(record, "cost"),
+    ...optionalModel(record["model"]),
+    ...optionalContextUsage(record["contextUsage"]),
+    ...optionalField("thinkingLevel", optionalString(record, "thinkingLevel")),
+  };
+}
+
+function parseTokens(value: unknown): SessionStatus["tokens"] {
+  const record = requireRecord(value);
+  return {
+    input: requireNumber(record, "input"),
+    output: requireNumber(record, "output"),
+    cacheRead: requireNumber(record, "cacheRead"),
+    cacheWrite: requireNumber(record, "cacheWrite"),
+    total: requireNumber(record, "total"),
+  };
+}
+
+function optionalModel(value: unknown): Pick<SessionStatus, "model"> | object {
+  if (value === undefined) return {};
+  const record = requireRecord(value);
+  return { model: { ...optionalField("provider", optionalString(record, "provider")), ...optionalField("id", optionalString(record, "id")), ...optionalField("name", optionalString(record, "name")), ...optionalField("contextWindow", optionalNumber(record, "contextWindow")), ...optionalField("reasoning", record["reasoning"]) } };
+}
+
+function optionalContextUsage(value: unknown): Pick<SessionStatus, "contextUsage"> | object {
+  if (value === undefined) return {};
+  const record = requireRecord(value);
+  return { contextUsage: { tokens: numberOrNull(record, "tokens"), contextWindow: requireNumber(record, "contextWindow"), percent: numberOrNull(record, "percent") } };
+}
+
+export function parseSlashCommand(value: unknown): SlashCommand {
+  const record = requireRecord(value);
+  const source = requireString(record, "source");
+  if (source !== "extension" && source !== "prompt" && source !== "skill" && source !== "builtin") throw new Error("Invalid command source");
+  return { name: requireString(record, "name"), source, ...optionalField("description", optionalString(record, "description")) };
+}
+
+export function parseFileSuggestion(value: unknown): FileSuggestion {
+  const record = requireRecord(value);
+  const kind = requireString(record, "kind");
+  if (kind !== "tracked" && kind !== "untracked" && kind !== "other") throw new Error("Invalid file kind");
+  return { path: requireString(record, "path"), kind };
+}
+
+export function parseFileTreeResponse(value: unknown): FileTreeResponse {
+  const record = requireRecord(value);
+  return { path: requireString(record, "path"), entries: arrayOf(parseFileTreeEntry)(record["entries"]), scannedAt: requireString(record, "scannedAt"), truncated: requireBoolean(record, "truncated") };
+}
+
+function parseFileTreeEntry(value: unknown): FileTreeEntry {
+  const record = requireRecord(value);
+  const type = requireString(record, "type");
+  if (type !== "file" && type !== "directory" && type !== "symlink") throw new Error("Invalid file tree entry type");
+  return { name: requireString(record, "name"), path: requireString(record, "path"), type, ...optionalField("size", optionalNumber(record, "size")), ...optionalField("modifiedAt", optionalString(record, "modifiedAt")) };
+}
+
+export function parseFileContentResponse(value: unknown): FileContentResponse {
+  const record = requireRecord(value);
+  const encoding = requireString(record, "encoding");
+  if (encoding !== "utf8") throw new Error("Invalid file encoding");
+  return { path: requireString(record, "path"), ...optionalField("language", optionalString(record, "language")), encoding, size: requireNumber(record, "size"), modifiedAt: requireString(record, "modifiedAt"), content: requireString(record, "content"), truncated: requireBoolean(record, "truncated"), binary: requireBoolean(record, "binary") };
+}
+
+export function parseGitStatusResponse(value: unknown): GitStatusResponse {
+  const record = requireRecord(value);
+  return { isGitRepo: requireBoolean(record, "isGitRepo"), hash: requireString(record, "hash"), ...optionalField("branch", optionalString(record, "branch")), ...optionalField("upstream", optionalString(record, "upstream")), ...optionalField("ahead", optionalNumber(record, "ahead")), ...optionalField("behind", optionalNumber(record, "behind")), files: arrayOf(parseGitStatusFile)(record["files"]) };
+}
+
+function parseGitStatusFile(value: unknown): GitStatusFile {
+  const record = requireRecord(value);
+  return { path: requireString(record, "path"), ...optionalField("oldPath", optionalString(record, "oldPath")), index: parseGitFileState(record["index"]), workingTree: parseGitFileState(record["workingTree"]) };
+}
+
+function parseGitFileState(value: unknown): GitFileState {
+  switch (value) {
+    case "unmodified":
+    case "modified":
+    case "added":
+    case "deleted":
+    case "renamed":
+    case "copied":
+    case "untracked":
+    case "ignored":
+    case "conflicted":
+      return value;
+    default:
+      throw new Error("Invalid git file state");
+  }
+}
+
+export function parseGitDiffResponse(value: unknown): GitDiffResponse {
+  const record = requireRecord(value);
+  return { ...optionalField("path", optionalString(record, "path")), staged: requireBoolean(record, "staged"), hash: requireString(record, "hash"), diff: requireString(record, "diff"), truncated: requireBoolean(record, "truncated") };
+}
+
+export function parseCommandResult(value: unknown): CommandResult {
+  const record = requireRecord(value);
+  const type = requireString(record, "type");
+  if (type === "unsupported") return { type, message: requireString(record, "message") };
+  if (type === "select") return { type, requestId: requireString(record, "requestId"), title: requireString(record, "title"), options: arrayOf(parseCommandOption)(record["options"]) };
+  if (type === "done") return { type, ...optionalField("message", optionalString(record, "message")), ...optionalSession(record["session"]) };
+  throw new Error("Invalid command result type");
+}
+
+function parseCommandOption(value: unknown): CommandOption {
+  const record = requireRecord(value);
+  return { value: requireString(record, "value"), label: requireString(record, "label"), ...optionalField("description", optionalString(record, "description")) };
+}
+
+function optionalSession(value: unknown): Pick<Extract<CommandResult, { type: "done" }>, "session"> | object {
+  return value === undefined ? {} : { session: parseSessionInfo(value) };
+}
+
+export function parseAccepted(value: unknown): { accepted: true } {
+  const record = requireRecord(value);
+  if (record["accepted"] !== true) throw new Error("Expected accepted response");
+  return { accepted: true };
+}
+
+export function parseAborted(value: unknown): { aborted: true } {
+  const record = requireRecord(value);
+  if (record["aborted"] !== true) throw new Error("Expected aborted response");
+  return { aborted: true };
+}
+
+export function parseStopped(value: unknown): { stopped: true } {
+  const record = requireRecord(value);
+  if (record["stopped"] !== true) throw new Error("Expected stopped response");
+  return { stopped: true };
+}
+
+export function parseArchived(value: unknown): { archived: true } {
+  const record = requireRecord(value);
+  if (record["archived"] !== true) throw new Error("Expected archived response");
+  return { archived: true };
+}
+
+export function parseRestored(value: unknown): { restored: true } {
+  const record = requireRecord(value);
+  if (record["restored"] !== true) throw new Error("Expected restored response");
+  return { restored: true };
+}
+
+function optionalNumber(record: Record<string, unknown>, key: string): number | undefined {
+  const value = record[key];
+  if (value === undefined) return undefined;
+  if (typeof value !== "number") throw new Error(`Expected optional number field: ${key}`);
+  return value;
+}
+
+function numberOrNull(record: Record<string, unknown>, key: string): number | null {
+  const value = record[key];
+  if (value === null) return null;
+  if (typeof value !== "number") throw new Error(`Expected number|null field: ${key}`);
+  return value;
+}
+
+function optionalField(key: string, value: unknown): object {
+  return value === undefined ? {} : { [key]: value };
+}
diff --git a/src/client/src/api/sockets.ts b/src/client/src/api/sockets.ts
new file mode 100644
index 0000000..762a106
--- /dev/null
+++ b/src/client/src/api/sockets.ts
@@ -0,0 +1,12 @@
+export function sessionEvents(sessionId: string): WebSocket {
+  return new WebSocket(`${webSocketBaseUrl()}/api/sessions/${sessionId}/events`);
+}
+
+export function globalSessionEvents(): WebSocket {
+  return new WebSocket(`${webSocketBaseUrl()}/api/sessions/events`);
+}
+
+function webSocketBaseUrl(): string {
+  const protocol = location.protocol === "https:" ? "wss:" : "ws:";
+  return `${protocol}//${location.host}`;
+}
diff --git a/src/client/src/api/urls.ts b/src/client/src/api/urls.ts
new file mode 100644
index 0000000..a7ac7ed
--- /dev/null
+++ b/src/client/src/api/urls.ts
@@ -0,0 +1,15 @@
+export function gitDiffUrl(projectId: string, workspaceId: string, options?: { path?: string; staged?: boolean }): string {
+  const params = new URLSearchParams();
+  if (options?.path !== undefined) params.set("path", options.path);
+  if (options?.staged === true) params.set("staged", "true");
+  const query = params.toString();
+  return `/api/projects/${encodeURIComponent(projectId)}/workspaces/${encodeURIComponent(workspaceId)}/git/diff${query ? `?${query}` : ""}`;
+}
+
+export function messageUrl(sessionId: string, options?: { limit?: number; before?: number }): string {
+  const params = new URLSearchParams();
+  if (options?.limit !== undefined) params.set("limit", String(options.limit));
+  if (options?.before !== undefined) params.set("before", String(options.before));
+  const query = params.toString();
+  return `/api/sessions/${sessionId}/messages${query ? `?${query}` : ""}`;
+}