diff --git a/src/client/src/api.ts b/src/client/src/api.ts
index f2296ae..c0a582a 100644
--- a/src/client/src/api.ts
+++ b/src/client/src/api.ts
@@ -24,6 +24,8 @@ export interface SessionInfo {
   modified: string;
   messageCount: number;
   firstMessage: string;
+  archived?: boolean;
+  archivedAt?: string;
 }
 
 export interface SessionActivity {
@@ -77,7 +79,7 @@ export type CommandResult =
 
 async function request<T>(url: string, parse: (value: unknown) => T, init?: RequestInit): Promise<T> {
   const headers = new Headers(init?.headers);
-  headers.set("content-type", "application/json");
+  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 => ({}));
@@ -107,6 +109,8 @@ export const api = {
   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 }) }),
   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 {
@@ -204,6 +208,7 @@ function parseWorkspace(value: unknown): Workspace {
 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"),
@@ -213,6 +218,8 @@ function parseSessionInfo(value: unknown): SessionInfo {
     modified: requireString(record, "modified"),
     messageCount: requireNumber(record, "messageCount"),
     firstMessage: requireString(record, "firstMessage"),
+    ...(record["archived"] === true ? { archived: true } : {}),
+    ...(archivedAt === undefined ? {} : { archivedAt }),
   };
 }
 
@@ -299,6 +306,18 @@ function parseStopped(value: unknown): { stopped: true } {
   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;
diff --git a/src/client/src/components/PiWebApp.ts b/src/client/src/components/PiWebApp.ts
index c5b5672..79b937f 100644
--- a/src/client/src/components/PiWebApp.ts
+++ b/src/client/src/components/PiWebApp.ts
@@ -109,13 +109,13 @@ export class PiWebApp extends LitElement {
           </header>
           <project-list .projects=${state.projects} .selected=${state.selectedProject} .onSelect=${(project: Project) => this.withChatScrollTransition(() => this.workspaces.selectProject(project))}></project-list>
           <workspace-list .workspaces=${state.workspaces} .selected=${state.selectedWorkspace} .onSelect=${(workspace: Workspace) => this.withChatScrollTransition(() => this.workspaces.selectWorkspace(workspace))}></workspace-list>
-          <session-list .sessions=${state.sessions} .statuses=${state.sessionStatuses} .activities=${state.sessionActivities} .selected=${state.selectedSession} .canStart=${!!state.selectedWorkspace} .onStart=${() => this.withChatScrollTransition(() => this.sessions.startSession())} .onSelect=${(session: SessionInfo) => this.withChatScrollTransition(() => this.sessions.selectSession(session))}></session-list>
+          <session-list .sessions=${state.sessions} .statuses=${state.sessionStatuses} .activities=${state.sessionActivities} .selected=${state.selectedSession} .canStart=${!!state.selectedWorkspace} .onStart=${() => this.withChatScrollTransition(() => this.sessions.startSession())} .onSelect=${(session: SessionInfo) => this.withChatScrollTransition(() => this.sessions.selectSession(session))} .onArchive=${(session: SessionInfo) => this.sessions.archiveSession(session)} .onRestore=${(session: SessionInfo) => this.sessions.restoreSession(session)}></session-list>
         </aside>
         <main>
           ${state.error ? html`<div class="error">${state.error}</div>` : null}
           ${state.selectedSession ? html`
             <chat-view .sessionId=${state.selectedSession.id} .messages=${state.messages} .messageStart=${state.messagePageStart} .messageTotal=${state.messagePageTotal} .hasMore=${state.messagePageStart > 0} .loadingMore=${state.isLoadingEarlierMessages} .isCompacting=${state.status?.isCompacting === true} .pendingMessageCount=${state.status?.pendingMessageCount ?? 0} .onLoadMore=${() => this.withChatPrependTransition(() => this.sessions.loadEarlierMessages())}></chat-view>
-            <prompt-editor .sessionId=${state.selectedSession.id} .cwd=${state.selectedWorkspace?.path} .canSteer=${state.status?.isStreaming === true} .isCompacting=${state.status?.isCompacting === true} .onSend=${(text: string, streamingBehavior?: "steer" | "followUp") => this.sessions.send(text, streamingBehavior)} .onStopSession=${() => this.sessions.stopSession()}></prompt-editor>
+            <prompt-editor .sessionId=${state.selectedSession.id} .cwd=${state.selectedWorkspace?.path} .disabled=${state.selectedSession.archived === true} .canSteer=${state.status?.isStreaming === true} .isCompacting=${state.status?.isCompacting === true} .onSend=${(text: string, streamingBehavior?: "steer" | "followUp") => this.sessions.send(text, streamingBehavior)} .onStopSession=${() => this.sessions.stopSession()}></prompt-editor>
             <status-bar .status=${state.status} .activity=${state.activity} .workspace=${state.selectedWorkspace}></status-bar>
             ${state.commandDialog !== undefined ? html`<command-picker .title=${state.commandDialog.title} .options=${state.commandDialog.options} .onPick=${(value: string) => this.sessions.respondToCommand(state.commandDialog?.requestId ?? "", value)} .onCancel=${() => { this.sessions.cancelCommand(); }}></command-picker>` : null}
           ` : html`<div class="empty">Select or start a session.</div>`}
diff --git a/src/client/src/components/SessionList.ts b/src/client/src/components/SessionList.ts
index 6888c2b..e842199 100644
--- a/src/client/src/components/SessionList.ts
+++ b/src/client/src/components/SessionList.ts
@@ -1,5 +1,5 @@
-import { LitElement, html } from "lit";
-import { customElement, property } from "lit/decorators.js";
+import { LitElement, html, type PropertyValues } from "lit";
+import { customElement, property, state } from "lit/decorators.js";
 import type { SessionActivity, SessionInfo, SessionStatus } from "../api";
 import { listStyles } from "./shared";
 
@@ -17,21 +17,69 @@ export class SessionList extends LitElement {
   @property({ type: Boolean }) canStart = false;
   @property({ attribute: false }) onSelect?: (session: SessionInfo) => void;
   @property({ attribute: false }) onStart?: () => void;
+  @state() private openMenuSessionId: string | undefined;
+  private readonly onDocumentClick = (event: MouseEvent) => {
+    if (event.composedPath().includes(this)) return;
+    this.openMenuSessionId = undefined;
+  };
+  @property({ attribute: false }) onArchive?: (session: SessionInfo) => void;
+  @property({ attribute: false }) onRestore?: (session: SessionInfo) => void;
+
+  override connectedCallback(): void {
+    super.connectedCallback();
+    document.addEventListener("click", this.onDocumentClick);
+  }
+
+  override disconnectedCallback(): void {
+    document.removeEventListener("click", this.onDocumentClick);
+    super.disconnectedCallback();
+  }
+
+  protected override updated(changed: PropertyValues<this>): void {
+    if (changed.has("sessions") && this.openMenuSessionId !== undefined && !this.sessions.some((session) => session.id === this.openMenuSessionId)) this.openMenuSessionId = undefined;
+  }
 
   override render() {
+    const active = this.sessions.filter((session) => session.archived !== true);
+    const archived = this.sessions.filter((session) => session.archived === true);
     return html`
       <section>
         <h2>Sessions <button ?disabled=${!this.canStart} @click=${() => this.onStart?.()}>+</button></h2>
-        ${this.sessions.map((session) => html`
-          <button class=${this.selected?.id === session.id ? "selected" : ""} @click=${() => this.onSelect?.(session)}>
-            <span>${sessionLabel(session)}</span><small>${this.renderStatus(session)}${String(session.messageCount)} messages</small>
-          </button>
-        `)}
+        ${active.map((session) => this.renderSession(session))}
+        ${archived.length > 0 ? html`
+          <h2 class="subheading">Archived</h2>
+          ${archived.map((session) => this.renderSession(session))}
+        ` : null}
       </section>
     `;
   }
 
+  private renderSession(session: SessionInfo) {
+    return html`
+      <div class="session-row ${this.selected?.id === session.id ? "selected" : ""} ${session.archived === true ? "archived" : ""}">
+        <button class="session-main" @click=${() => this.onSelect?.(session)}>
+          <span>${sessionLabel(session)}</span><small>${this.renderStatus(session)}${String(session.messageCount)} messages</small>
+        </button>
+        <div class="session-menu">
+          <button class="session-menu-toggle" title="Session actions" @click=${(event: MouseEvent) => { event.stopPropagation(); this.toggleMenu(session.id); }}>⋯</button>
+          ${this.openMenuSessionId === session.id ? html`
+            <div class="session-menu-panel">
+              ${session.archived === true
+                ? html`<button title="Restore session" @click=${() => { this.openMenuSessionId = undefined; this.onRestore?.(session); }}>Restore</button>`
+                : html`<button title="Archive session" @click=${() => { this.openMenuSessionId = undefined; this.onArchive?.(session); }}>Archive</button>`}
+            </div>
+          ` : null}
+        </div>
+      </div>
+    `;
+  }
+
+  private toggleMenu(sessionId: string) {
+    this.openMenuSessionId = this.openMenuSessionId === sessionId ? undefined : sessionId;
+  }
+
   private renderStatus(session: SessionInfo) {
+    if (session.archived === true) return "read-only · ";
     const status = this.statuses[session.id];
     const activity = this.activities[session.id];
     if (activity?.phase === "active") return `● ${activity.label} · `;
diff --git a/src/client/src/components/shared.ts b/src/client/src/components/shared.ts
index c7d47ea..68465e1 100644
--- a/src/client/src/components/shared.ts
+++ b/src/client/src/components/shared.ts
@@ -45,6 +45,16 @@ export const listStyles = css`
   h2 { display: flex; justify-content: space-between; align-items: center; margin: 0 0 8px; color: #8b949e; font-size: 12px; text-transform: uppercase; }
   button { border: 1px solid #30363d; border-radius: 8px; background: #161b22; color: #e6edf3; padding: 7px 9px; cursor: pointer; }
   section > button { display: block; width: 100%; text-align: left; margin: 6px 0; }
+  .subheading { margin-top: 14px; }
+  .session-row { position: relative; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 6px; margin: 6px 0; }
+  .session-row.selected .session-main { border-color: #58a6ff; background: #0d2847; }
+  .session-row.archived .session-main { color: #8b949e; }
+  .session-main { min-width: 0; text-align: left; }
+  .session-menu { position: relative; align-self: stretch; }
+  .session-menu-toggle { display: grid; place-items: center; height: 100%; min-width: 30px; padding: 0; color: #8b949e; }
+  .session-menu-panel { position: absolute; right: 0; top: calc(100% + 4px); z-index: 5; min-width: 120px; padding: 4px; border: 1px solid #30363d; border-radius: 8px; background: #161b22; box-shadow: 0 8px 24px #0008; }
+  .session-menu-panel button { display: block; width: 100%; text-align: left; border: 0; background: transparent; color: #e6edf3; }
+  .session-menu-panel button:hover { background: #0d2847; }
   button.selected { border-color: #58a6ff; background: #0d2847; }
   button:disabled { opacity: .5; cursor: not-allowed; }
   small { display: block; color: #8b949e; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
diff --git a/src/client/src/controllers/sessionController.ts b/src/client/src/controllers/sessionController.ts
index a6b2230..dfdb32e 100644
--- a/src/client/src/controllers/sessionController.ts
+++ b/src/client/src/controllers/sessionController.ts
@@ -46,6 +46,13 @@ export class SessionController {
   async selectSession(session: SessionInfo, options?: { updateUrl?: boolean | undefined }) {
     this.socket.close();
     try {
+      if (session.archived === true) {
+        const page = await api.messages(session.id, { limit: MESSAGE_PAGE_SIZE });
+        const history = this.mergeAndCacheHistory(session.id, page);
+        this.setState({ selectedSession: session, messages: normalizeMessages(history.messages), messagePageStart: history.start, messagePageTotal: history.total, isLoadingEarlierMessages: false, status: undefined, activity: undefined });
+        if (options?.updateUrl !== false) this.updateUrl();
+        return;
+      }
       const buffered: SessionUiEvent[] = [];
       this.socket.connect(session.id, (event) => buffered.push(event));
       const [page, status] = await Promise.all([api.messages(session.id, { limit: MESSAGE_PAGE_SIZE }), api.status(session.id)]);
@@ -86,7 +93,7 @@ export class SessionController {
     if (trimmed.startsWith("/")) return this.runCommand(text);
     if (isShellInput(text)) return this.runShell(text);
     const session = this.getState().selectedSession;
-    if (!session) return;
+    if (!session || session.archived === true) return;
     this.setState({ messages: [...this.getState().messages, textMessage("user", text)] });
     try {
       await api.prompt(session.id, text, streamingBehavior);
@@ -97,7 +104,7 @@ export class SessionController {
 
   async runShell(text: string) {
     const session = this.getState().selectedSession;
-    if (!session) return;
+    if (!session || session.archived === true) return;
     this.setState({ messages: [...this.getState().messages, textMessage("user", text)] });
     try {
       await api.shell(session.id, text);
@@ -108,7 +115,7 @@ export class SessionController {
 
   async runCommand(text: string) {
     const session = this.getState().selectedSession;
-    if (!session) return;
+    if (!session || session.archived === true) return;
     this.setState({ messages: [...this.getState().messages, textMessage("user", text)] });
     try {
       this.applyCommandResult(await api.runCommand(session.id, text));
@@ -132,6 +139,34 @@ export class SessionController {
     this.setState({ commandDialog: undefined });
   }
 
+  async archiveSession(session = this.getState().selectedSession) {
+    if (!session) return;
+    try {
+      await api.archive(session.id);
+      this.replaceSession({ ...session, archived: true, archivedAt: new Date().toISOString() });
+      if (this.getState().selectedSession?.id === session.id) {
+        this.socket.close();
+        this.setState({ status: undefined, activity: undefined });
+      }
+    } catch (error) {
+      this.setState({ error: String(error) });
+    }
+  }
+
+  async restoreSession(session = this.getState().selectedSession) {
+    if (!session) return;
+    try {
+      await api.restore(session.id);
+      const restored = { ...session };
+      delete restored.archived;
+      delete restored.archivedAt;
+      this.replaceSession(restored);
+      if (this.getState().selectedSession?.id === restored.id) await this.selectSession(restored);
+    } catch (error) {
+      this.setState({ error: String(error) });
+    }
+  }
+
   async stopSession() {
     const session = this.getState().selectedSession;
     if (!session) return;
@@ -145,6 +180,14 @@ export class SessionController {
     }
   }
 
+  private replaceSession(session: SessionInfo) {
+    const current = this.getState().selectedSession;
+    this.setState({
+      sessions: this.getState().sessions.map((candidate) => candidate.id === session.id ? session : candidate),
+      selectedSession: current?.id === session.id ? session : current,
+    });
+  }
+
   private mergeAndCacheHistory(sessionId: string, page: RawMessagePage): RawMessagePage {
     const history = mergeChatHistory(readChatHistoryCache(sessionId), page);
     writeChatHistoryCache(sessionId, history);
diff --git a/src/client/src/controllers/workspaceController.ts b/src/client/src/controllers/workspaceController.ts
index 57c79fd..27e39b9 100644
--- a/src/client/src/controllers/workspaceController.ts
+++ b/src/client/src/controllers/workspaceController.ts
@@ -31,7 +31,7 @@ export class WorkspaceController {
       const sessions = await api.sessions(workspace.path);
       this.setState({ sessions });
       const sessionId = target?.sessionId;
-      const session = sessionId !== undefined && sessionId !== "" ? sessions.find((s) => s.id === sessionId || s.id.startsWith(sessionId)) : sessions[0];
+      const session = sessionId !== undefined && sessionId !== "" ? sessions.find((s) => s.id === sessionId || s.id.startsWith(sessionId)) : sessions.find((s) => s.archived !== true);
       if (session) await this.sessions.selectSession(session, { updateUrl: target?.updateUrl });
       else if (target?.updateUrl !== false) this.updateUrl();
     } catch (error) {
diff --git a/src/server/sessiond/sessionProxyRoutes.ts b/src/server/sessiond/sessionProxyRoutes.ts
index b47cd29..23ec538 100644
--- a/src/server/sessiond/sessionProxyRoutes.ts
+++ b/src/server/sessiond/sessionProxyRoutes.ts
@@ -27,6 +27,8 @@ export function registerSessionProxyRoutes(app: FastifyInstance, daemon = new Se
   app.post<{ Params: { sessionId: string }; Body: { requestId: string; value: string } }>("/api/sessions/:sessionId/commands/respond", (request, reply) => proxy(request, reply));
   app.post<{ Params: { sessionId: string } }>("/api/sessions/:sessionId/abort", (request, reply) => proxy(request, reply));
   app.post<{ Params: { sessionId: string } }>("/api/sessions/:sessionId/stop", (request, reply) => proxy(request, reply));
+  app.post<{ Params: { sessionId: string } }>("/api/sessions/:sessionId/archive", (request, reply) => proxy(request, reply));
+  app.post<{ Params: { sessionId: string } }>("/api/sessions/:sessionId/restore", (request, reply) => proxy(request, reply));
 
   app.get<{ Params: { sessionId: string } }>("/api/sessions/:sessionId/events", { websocket: true }, (socket, request) => {
     bridgeSockets(socket, daemon.connectWebSocket(`/sessions/${request.params.sessionId}/events`));
diff --git a/src/server/sessions/piSessionService.ts b/src/server/sessions/piSessionService.ts
index 5a7b9f5..f42617e 100644
--- a/src/server/sessions/piSessionService.ts
+++ b/src/server/sessions/piSessionService.ts
@@ -13,6 +13,7 @@ import type { ClientCommand, ClientCommandResult, ClientMessagePage, ClientSessi
 import type { SessionEventHub } from "../realtime/sessionEventHub.js";
 import { BUILTIN_COMMANDS } from "./builtinCommands.js";
 import { SessionCommandService } from "./sessionCommandService.js";
+import { SessionArchiveStore } from "./sessionArchiveStore.js";
 import type { ActiveSession } from "./sessionRuntimeStore.js";
 
 function noop(): void {
@@ -24,6 +25,7 @@ export class PiSessionService {
   private readonly activities = new Map<string, { phase: "active" | "idle" | "error"; label: string; detail?: string; at: string }>();
   private readonly heartbeat: NodeJS.Timeout;
   private readonly commandService: SessionCommandService;
+  private readonly archiveStore = new SessionArchiveStore();
   private readonly agentDir = getAgentDir();
   private readonly authStorage = AuthStorage.create();
   private readonly modelRegistry = ModelRegistry.create(this.authStorage);
@@ -46,17 +48,22 @@ export class PiSessionService {
   }
 
   async list(cwd: string): Promise<ClientSession[]> {
-    const sessions = await SessionManager.list(cwd);
-    return sessions.map((s) => ({
-      id: s.id,
-      path: s.path,
-      cwd: s.cwd,
-      ...(s.name === undefined ? {} : { name: s.name }),
-      created: s.created.toISOString(),
-      modified: s.modified.toISOString(),
-      messageCount: s.messageCount,
-      firstMessage: s.firstMessage,
-    }));
+    const [sessions, archivedRecords] = await Promise.all([SessionManager.list(cwd), this.archiveStore.list()]);
+    const archivedById = new Map(archivedRecords.filter((record) => record.cwd === cwd).map((record) => [record.sessionId, record]));
+    return sessions.map((s) => {
+      const archived = archivedById.get(s.id);
+      return {
+        id: s.id,
+        path: s.path,
+        cwd: s.cwd,
+        ...(s.name === undefined ? {} : { name: s.name }),
+        created: s.created.toISOString(),
+        modified: s.modified.toISOString(),
+        messageCount: s.messageCount,
+        firstMessage: s.firstMessage,
+        ...(archived === undefined ? {} : { archived: true, archivedAt: archived.archivedAt }),
+      };
+    });
   }
 
   async start(cwd: string): Promise<ClientSession> {
@@ -104,6 +111,7 @@ export class PiSessionService {
   }
 
   async prompt(sessionId: string, text: string, streamingBehavior?: "steer" | "followUp"): Promise<void> {
+    await this.assertWritable(sessionId);
     const session = await this.getOrOpen(sessionId);
     const behavior = session.isStreaming || session.isCompacting ? streamingBehavior ?? "followUp" : undefined;
     this.publishActivity(session, session.isCompacting ? "message queued during compaction" : behavior === "steer" ? "steering queued" : behavior === "followUp" ? "message queued" : "prompt accepted", "active");
@@ -115,6 +123,7 @@ export class PiSessionService {
   }
 
   async shell(sessionId: string, text: string): Promise<void> {
+    await this.assertWritable(sessionId);
     const active = await this.getActive(sessionId);
     const { session } = active.runtime;
     const isExcluded = text.startsWith("!!");
@@ -149,13 +158,26 @@ export class PiSessionService {
   }
 
   async runCommand(sessionId: string, text: string): Promise<ClientCommandResult> {
+    await this.assertWritable(sessionId);
     return this.commandService.run(sessionId, text);
   }
 
   async respondToCommand(sessionId: string, requestId: string, value: string): Promise<ClientCommandResult> {
+    await this.assertWritable(sessionId);
     return this.commandService.respond(sessionId, requestId, value);
   }
 
+  async archive(sessionId: string): Promise<void> {
+    const session = await this.getOrOpen(sessionId);
+    if (session.isStreaming || session.isCompacting || session.isBashRunning || session.pendingMessageCount > 0) throw new Error("Stop current session activity before archiving");
+    await this.archiveStore.archive(sessionId, session.sessionManager.getCwd());
+    this.stop(sessionId);
+  }
+
+  async restore(sessionId: string): Promise<void> {
+    await this.archiveStore.restore(sessionId);
+  }
+
   async abort(sessionId: string): Promise<void> {
     const active = this.active.get(sessionId);
     if (active) await active.runtime.session.abort();
@@ -170,6 +192,10 @@ export class PiSessionService {
     this.activities.delete(sessionId);
   }
 
+  private async assertWritable(sessionId: string): Promise<void> {
+    if (await this.archiveStore.isArchived(sessionId)) throw new Error("Archived sessions are read-only. Restore the session to continue.");
+  }
+
   private async getOrOpen(sessionId: string): Promise<AgentSession> {
     return (await this.getActive(sessionId)).runtime.session;
   }
diff --git a/src/server/sessions/sessionArchiveStore.ts b/src/server/sessions/sessionArchiveStore.ts
new file mode 100644
index 0000000..f6c2da4
--- /dev/null
+++ b/src/server/sessions/sessionArchiveStore.ts
@@ -0,0 +1,79 @@
+import { mkdir, readFile, writeFile } from "node:fs/promises";
+import { dirname, join } from "node:path";
+import { homedir } from "node:os";
+
+export interface ArchivedSessionRecord {
+  sessionId: string;
+  cwd: string;
+  archivedAt: string;
+}
+
+interface ArchiveFile {
+  sessions: ArchivedSessionRecord[];
+}
+
+export class SessionArchiveStore {
+  constructor(private readonly filePath = join(homedir(), ".pi-web", "archived-sessions.json")) {}
+
+  async list(): Promise<ArchivedSessionRecord[]> {
+    return (await this.read()).sessions;
+  }
+
+  async archive(sessionId: string, cwd: string): Promise<ArchivedSessionRecord> {
+    const data = await this.read();
+    const existing = data.sessions.find((session) => session.sessionId === sessionId);
+    if (existing !== undefined) return existing;
+    const record = { sessionId, cwd, archivedAt: new Date().toISOString() };
+    data.sessions.push(record);
+    await this.write(data);
+    return record;
+  }
+
+  async restore(sessionId: string): Promise<void> {
+    const data = await this.read();
+    const sessions = data.sessions.filter((session) => session.sessionId !== sessionId);
+    if (sessions.length === data.sessions.length) return;
+    await this.write({ sessions });
+  }
+
+  async isArchived(sessionId: string): Promise<boolean> {
+    return (await this.list()).some((session) => session.sessionId === sessionId);
+  }
+
+  private async read(): Promise<ArchiveFile> {
+    try {
+      const value: unknown = JSON.parse(await readFile(this.filePath, "utf8"));
+      return parseArchiveFile(value);
+    } catch (error: unknown) {
+      if (isNodeErrorWithCode(error, "ENOENT")) return { sessions: [] };
+      throw error;
+    }
+  }
+
+  private async write(data: ArchiveFile): Promise<void> {
+    await mkdir(dirname(this.filePath), { recursive: true });
+    await writeFile(this.filePath, `${JSON.stringify(data, null, 2)}\n`, "utf8");
+  }
+}
+
+function parseArchiveFile(value: unknown): ArchiveFile {
+  if (!isRecord(value) || !Array.isArray(value["sessions"])) throw new Error("Invalid archive file");
+  return { sessions: value["sessions"].map(parseArchivedSessionRecord) };
+}
+
+function parseArchivedSessionRecord(value: unknown): ArchivedSessionRecord {
+  if (!isRecord(value)) throw new Error("Invalid archived session record");
+  const sessionId = value["sessionId"];
+  const cwd = value["cwd"];
+  const archivedAt = value["archivedAt"];
+  if (typeof sessionId !== "string" || typeof cwd !== "string" || typeof archivedAt !== "string") throw new Error("Invalid archived session record");
+  return { sessionId, cwd, archivedAt };
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null;
+}
+
+function isNodeErrorWithCode(error: unknown, code: string): error is NodeJS.ErrnoException {
+  return error instanceof Error && "code" in error && error.code === code;
+}
diff --git a/src/server/sessions/sessionRoutes.ts b/src/server/sessions/sessionRoutes.ts
index 563ca83..5722c14 100644
--- a/src/server/sessions/sessionRoutes.ts
+++ b/src/server/sessions/sessionRoutes.ts
@@ -85,6 +85,24 @@ export function registerSessionRoutes(app: FastifyInstance, sessions: PiSessionS
     return { stopped: true };
   });
 
+  app.post<{ Params: { sessionId: string } }>(`${prefix}/sessions/:sessionId/archive`, async (request, reply) => {
+    try {
+      await sessions.archive(request.params.sessionId);
+      return { archived: true };
+    } catch (error) {
+      return reply.code(400).send({ error: error instanceof Error ? error.message : String(error) });
+    }
+  });
+
+  app.post<{ Params: { sessionId: string } }>(`${prefix}/sessions/:sessionId/restore`, async (request, reply) => {
+    try {
+      await sessions.restore(request.params.sessionId);
+      return { restored: true };
+    } catch (error) {
+      return reply.code(400).send({ error: error instanceof Error ? error.message : String(error) });
+    }
+  });
+
   app.get<{ Params: { sessionId: string } }>(`${prefix}/sessions/:sessionId/events`, { websocket: true }, (socket, request) => {
     eventHub.add(request.params.sessionId, socket);
   });
diff --git a/src/server/types.ts b/src/server/types.ts
index 22f0614..e0ab9e4 100644
--- a/src/server/types.ts
+++ b/src/server/types.ts
@@ -24,6 +24,8 @@ export interface ClientSession {
   modified: string;
   messageCount: number;
   firstMessage: string;
+  archived?: boolean;
+  archivedAt?: string;
 }
 
 export interface ClientMessagePage {