feat: preserve browser-cached new sessions

.changeset/browser-cached-new-sessions.md

@@ -0,0 +1,5 @@
+---
+"@jmfederico/pi-web": patch
+---
+
+Preserve newly started empty sessions and their prompt drafts across browser reloads until the user deletes them.

src/client/src/cachedNewSessions.test.ts

@@ -0,0 +1,74 @@
+import { describe, expect, it } from "vitest";
+import type { SessionInfo } from "./api";
+import { forgetCachedNewSession, isCachedNewSessionInfo, loadCachedNewSessions, mergeCachedNewSessions, rememberCachedNewSession } from "./cachedNewSessions";
+
+class MemoryStorage implements Storage {
+  private readonly values = new Map<string, string>();
+
+  get length(): number {
+    return this.values.size;
+  }
+
+  clear(): void {
+    this.values.clear();
+  }
+
+  getItem(key: string): string | null {
+    return this.values.get(key) ?? null;
+  }
+
+  key(index: number): string | null {
+    return Array.from(this.values.keys())[index] ?? null;
+  }
+
+  removeItem(key: string): void {
+    this.values.delete(key);
+  }
+
+  setItem(key: string, value: string): void {
+    this.values.set(key, value);
+  }
+}
+
+const baseSession: SessionInfo = {
+  id: "session-1",
+  path: "/tmp/session-1.jsonl",
+  cwd: "/repo",
+  created: "2026-05-15T00:00:00.000Z",
+  modified: "2026-05-15T00:00:00.000Z",
+  messageCount: 0,
+  firstMessage: "",
+};
+
+describe("cached new sessions", () => {
+  it("stores and reloads new sessions with a browser-cache marker", () => {
+    const storage = new MemoryStorage();
+
+    rememberCachedNewSession(baseSession, storage);
+
+    const cached = loadCachedNewSessions(storage);
+    expect(cached).toHaveLength(1);
+    expect(cached[0]?.id).toBe("session-1");
+    expect(isCachedNewSessionInfo(cached[0])).toBe(true);
+  });
+
+  it("merges cached sessions for the selected cwd without duplicating server sessions", () => {
+    const storage = new MemoryStorage();
+    rememberCachedNewSession(baseSession, storage);
+    rememberCachedNewSession({ ...baseSession, id: "other", cwd: "/other" }, storage);
+
+    expect(mergeCachedNewSessions("/repo", [], storage).map((session) => session.id)).toEqual(["session-1"]);
+    expect(mergeCachedNewSessions("/repo", [baseSession], storage).map((session) => session.id)).toEqual(["session-1"]);
+    expect(isCachedNewSessionInfo(mergeCachedNewSessions("/repo", [baseSession], storage)[0])).toBe(false);
+    expect(loadCachedNewSessions(storage).map((session) => session.id)).toEqual(["other"]);
+  });
+
+  it("forgets cached sessions", () => {
+    const storage = new MemoryStorage();
+    rememberCachedNewSession(baseSession, storage);
+
+    forgetCachedNewSession("session-1", storage);
+
+    expect(loadCachedNewSessions(storage)).toEqual([]);
+  });
+});

src/client/src/cachedNewSessions.ts

@@ -0,0 +1,129 @@
+import type { SessionInfo } from "./api";
+
+const storageKey = "pi-web:cached-new-sessions:v1";
+const markerProperty = "browserCachedNew";
+
+export type CachedNewSessionInfo = SessionInfo & { browserCachedNew: true };
+
+function browserStorage(): Storage | undefined {
+  try {
+    return typeof localStorage === "undefined" ? undefined : localStorage;
+  } catch {
+    return undefined;
+  }
+}
+
+export function rememberCachedNewSession(session: SessionInfo, storage = browserStorage()): void {
+  if (session.messageCount !== 0 || session.archived === true) return;
+  const sessions = loadCachedNewSessions(storage).filter((candidate) => candidate.id !== session.id);
+  saveCachedNewSessions([markCachedNewSessionInfo(session), ...sessions], storage);
+}
+
+export function markCachedNewSessionInfo(session: SessionInfo): CachedNewSessionInfo {
+  return { ...session, browserCachedNew: true };
+}
+
+export function forgetCachedNewSession(sessionId: string, storage = browserStorage()): void {
+  const sessions = loadCachedNewSessions(storage).filter((session) => session.id !== sessionId);
+  saveCachedNewSessions(sessions, storage);
+}
+
+export function mergeCachedNewSessions(cwd: string, sessions: SessionInfo[], storage = browserStorage()): SessionInfo[] {
+  const sessionIds = new Set(sessions.map((session) => session.id));
+  const cachedSessions = loadCachedNewSessions(storage);
+  const retainedCachedSessions = cachedSessions.filter((session) => !sessionIds.has(session.id));
+  if (retainedCachedSessions.length !== cachedSessions.length) saveCachedNewSessions(retainedCachedSessions, storage);
+  const cached = retainedCachedSessions.filter((session) => session.cwd === cwd);
+  return [...cached, ...sessions];
+}
+
+export function isCachedNewSessionInfo(session: SessionInfo | undefined): session is CachedNewSessionInfo {
+  if (session === undefined) return false;
+  return hasCachedNewMarker(session) && session.browserCachedNew === true;
+}
+
+export function stripCachedNewSessionMarker(session: SessionInfo): SessionInfo {
+  return {
+    id: session.id,
+    path: session.path,
+    cwd: session.cwd,
+    ...(session.name === undefined ? {} : { name: session.name }),
+    created: session.created,
+    modified: session.modified,
+    messageCount: session.messageCount,
+    firstMessage: session.firstMessage,
+    ...(session.parentSessionPath === undefined ? {} : { parentSessionPath: session.parentSessionPath }),
+    ...(session.archived === true ? { archived: true } : {}),
+    ...(session.archivedAt === undefined ? {} : { archivedAt: session.archivedAt }),
+  };
+}
+
+export function loadCachedNewSessions(storage = browserStorage()): CachedNewSessionInfo[] {
+  try {
+    const raw = storage?.getItem(storageKey);
+    if (raw === undefined || raw === null || raw === "") return [];
+    const value: unknown = JSON.parse(raw);
+    if (!Array.isArray(value)) return [];
+    return value.flatMap((candidate) => parseCachedSession(candidate));
+  } catch {
+    return [];
+  }
+}
+
+function saveCachedNewSessions(sessions: CachedNewSessionInfo[], storage = browserStorage()): void {
+  try {
+    if (sessions.length === 0) storage?.removeItem(storageKey);
+    else storage?.setItem(storageKey, JSON.stringify(sessions));
+  } catch {
+    // Ignore localStorage quota/privacy errors.
+  }
+}
+
+function parseCachedSession(value: unknown): CachedNewSessionInfo[] {
+  if (!isRecord(value)) return [];
+  const id = stringField(value, "id");
+  const path = stringField(value, "path");
+  const cwd = stringField(value, "cwd");
+  const created = stringField(value, "created");
+  const modified = stringField(value, "modified");
+  const firstMessage = stringField(value, "firstMessage");
+  const messageCount = numberField(value, "messageCount");
+  if (id === undefined || path === undefined || cwd === undefined || created === undefined || modified === undefined || firstMessage === undefined || messageCount !== 0) return [];
+  const name = optionalStringField(value, "name");
+  const parentSessionPath = optionalStringField(value, "parentSessionPath");
+  return [{
+    id,
+    path,
+    cwd,
+    ...(name === undefined ? {} : { name }),
+    created,
+    modified,
+    messageCount,
+    firstMessage,
+    ...(parentSessionPath === undefined ? {} : { parentSessionPath }),
+    browserCachedNew: true,
+  }];
+}
+
+function hasCachedNewMarker(session: SessionInfo): session is SessionInfo & { browserCachedNew: unknown } {
+  return markerProperty in session;
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null;
+}
+
+function stringField(record: Record<string, unknown>, key: string): string | undefined {
+  const value = record[key];
+  return typeof value === "string" ? value : undefined;
+}
+
+function optionalStringField(record: Record<string, unknown>, key: string): string | undefined {
+  const value = record[key];
+  return value === undefined || typeof value !== "string" ? undefined : value;
+}
+
+function numberField(record: Record<string, unknown>, key: string): number | undefined {
+  const value = record[key];
+  return typeof value === "number" ? value : undefined;
+}

src/client/src/components/PiWebApp.ts

@@ -268,7 +268,7 @@ export class PiWebApp extends LitElement {
       </header>
       <project-list .projects=${this.state.projects} .selected=${this.state.selectedProject} .onSelect=${(project: Project) => this.withChatScrollTransition(() => this.workspaces.selectProject(project))} .onClose=${(project: Project) => this.projects.closeProject(project.id)}></project-list>
       <workspace-list .workspaces=${this.state.workspaces} .selected=${this.state.selectedWorkspace} .workspaceLabelItems=${(workspace: Workspace) => this.plugins.getWorkspaceLabelItems(this.state, workspace)} .onSelect=${(workspace: Workspace) => this.withChatScrollTransition(() => this.workspaces.selectWorkspace(workspace))}></workspace-list>
-      <session-list .sessions=${this.state.sessions} .statuses=${this.state.sessionStatuses} .activities=${this.state.sessionActivities} .selected=${this.state.selectedSession} .canStart=${!!this.state.selectedWorkspace} .onStart=${() => openChatAfter(() => this.sessions.startSession())} .onSelect=${(session: SessionInfo) => openChatAfter(() => this.sessions.selectSession(session))} .onArchive=${(session: SessionInfo) => this.sessions.archiveSession(session)} .onRestore=${(session: SessionInfo) => openChatAfter(() => this.sessions.restoreSession(session))} .onDetachParent=${(session: SessionInfo) => this.sessions.detachParent(session)}></session-list>
+      <session-list .sessions=${this.state.sessions} .statuses=${this.state.sessionStatuses} .activities=${this.state.sessionActivities} .selected=${this.state.selectedSession} .canStart=${!!this.state.selectedWorkspace} .onStart=${() => openChatAfter(() => this.sessions.startSession())} .onSelect=${(session: SessionInfo) => openChatAfter(() => this.sessions.selectSession(session))} .onArchive=${(session: SessionInfo) => this.sessions.archiveSession(session)} .onRestore=${(session: SessionInfo) => openChatAfter(() => this.sessions.restoreSession(session))} .onDelete=${(session: SessionInfo) => this.sessions.deleteCachedNewSession(session)} .onDetachParent=${(session: SessionInfo) => this.sessions.detachParent(session)}></session-list>
     `;
   }
 

src/client/src/components/PromptEditor.ts

@@ -7,6 +7,7 @@ import { LitElement, html, type PropertyValues } from "lit";
 import { customElement, property, query, state } from "lit/decorators.js";
 import { api, type FileSuggestion, type SessionStatus, type SlashCommand } from "../api";
 import { inputModeForDraft } from "../inputModes";
+import { clearDraft, loadDraft, saveDraft } from "../promptDraftStorage";
 import { promptEditorStyles, type CompletionItem } from "./shared";
 import "./AutocompleteMenu";
 
@@ -298,33 +299,3 @@ function emptyFileSuggestions(): FileSuggestion[] {
   return [];
 }
 
-const draftStoragePrefix = "pi-web:prompt-draft:";
-
-function draftStorageKey(sessionId: string): string {
-  return `${draftStoragePrefix}${sessionId}`;
-}
-
-function loadDraft(sessionId: string): string {
-  try {
-    return localStorage.getItem(draftStorageKey(sessionId)) ?? "";
-  } catch {
-    return "";
-  }
-}
-
-function saveDraft(sessionId: string, draft: string): void {
-  try {
-    if (draft) localStorage.setItem(draftStorageKey(sessionId), draft);
-    else localStorage.removeItem(draftStorageKey(sessionId));
-  } catch {
-    // Ignore localStorage quota/privacy errors.
-  }
-}
-
-function clearDraft(sessionId: string): void {
-  try {
-    localStorage.removeItem(draftStorageKey(sessionId));
-  } catch {
-    // Ignore localStorage quota/privacy errors.
-  }
-}

src/client/src/components/SessionList.ts

@@ -1,6 +1,7 @@
 import { LitElement, html, type PropertyValues } from "lit";
 import { customElement, property, state } from "lit/decorators.js";
 import type { SessionActivity, SessionInfo, SessionStatus } from "../api";
+import { isCachedNewSessionInfo } from "../cachedNewSessions";
 import { activateSelectableRow, activateSelectableRowFromKeyboard } from "./selectableRow";
 import { listStyles } from "./shared";
 
@@ -33,6 +34,7 @@ export class SessionList extends LitElement {
   };
   @property({ attribute: false }) onArchive?: (session: SessionInfo) => void;
   @property({ attribute: false }) onRestore?: (session: SessionInfo) => void;
+  @property({ attribute: false }) onDelete?: (session: SessionInfo) => void;
   @property({ attribute: false }) onDetachParent?: (session: SessionInfo) => void;
 
   override connectedCallback(): void {
@@ -92,9 +94,11 @@ export class SessionList extends LitElement {
           ${this.openMenuSessionId === session.id ? html`
             <div class="action-menu-panel" style=${this.menuStyle}>
               ${session.parentSessionPath !== undefined ? html`<button title="Detach from parent" @click=${() => { this.openMenuSessionId = undefined; this.onDetachParent?.(session); }}>Detach from parent</button>` : null}
-              ${session.archived === true
-                ? html`<button title="Restore session" @click=${() => { this.openMenuSessionId = undefined; this.onRestore?.(session); }}>Restore</button>`
-                : html`<button title="Archive session" @click=${() => { this.openMenuSessionId = undefined; this.onArchive?.(session); }}>Archive</button>`}
+              ${isCachedNewSessionInfo(session)
+                ? html`<button title="Delete browser-cached new session" @click=${() => { this.openMenuSessionId = undefined; this.onDelete?.(session); }}>Delete</button>`
+                : 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>
@@ -124,6 +128,7 @@ export class SessionList extends LitElement {
   }
 
   private renderStatus(session: SessionInfo) {
+    if (isCachedNewSessionInfo(session)) return "new · ";
     if (session.archived === true) return "read-only · ";
     const status = this.statuses[session.id];
     const activity = this.activities[session.id];

src/client/src/controllers/sessionController.test.ts

@@ -0,0 +1,134 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { api as defaultApi, type MessagePage, type SessionInfo, type SessionStatus, type Workspace } from "../api";
+import { loadCachedNewSessions, markCachedNewSessionInfo, rememberCachedNewSession } from "../cachedNewSessions";
+import { initialAppState, type AppState } from "../appState";
+import { loadDraft, saveDraft } from "../promptDraftStorage";
+import { SessionController, type SessionEventSocket } from "./sessionController";
+
+class MemoryStorage implements Storage {
+  private readonly values = new Map<string, string>();
+
+  get length(): number {
+    return this.values.size;
+  }
+
+  clear(): void {
+    this.values.clear();
+  }
+
+  getItem(key: string): string | null {
+    return this.values.get(key) ?? null;
+  }
+
+  key(index: number): string | null {
+    return Array.from(this.values.keys())[index] ?? null;
+  }
+
+  removeItem(key: string): void {
+    this.values.delete(key);
+  }
+
+  setItem(key: string, value: string): void {
+    this.values.set(key, value);
+  }
+}
+
+class FakeSocket implements SessionEventSocket {
+  readonly connectedSessionIds: string[] = [];
+
+  connect(sessionId: string): void {
+    this.connectedSessionIds.push(sessionId);
+  }
+
+  setHandler(): void {
+    // Test socket does not emit events.
+  }
+
+  close(): void {
+    // No-op.
+  }
+}
+
+const workspace: Workspace = {
+  id: "workspace-1",
+  projectId: "project-1",
+  path: "/repo",
+  label: "repo",
+  isMain: true,
+  isGitRepo: true,
+  isGitWorktree: false,
+};
+
+const oldSession: SessionInfo = {
+  id: "old-session",
+  path: "/tmp/old-session.jsonl",
+  cwd: "/repo",
+  created: "2026-05-15T00:00:00.000Z",
+  modified: "2026-05-15T00:00:00.000Z",
+  messageCount: 0,
+  firstMessage: "",
+};
+
+const replacementSession: SessionInfo = {
+  ...oldSession,
+  id: "new-session",
+  path: "/tmp/new-session.jsonl",
+};
+
+const emptyPage: MessagePage = { messages: [], start: 0, total: 0 };
+
+function status(sessionId: string): SessionStatus {
+  return {
+    sessionId,
+    isStreaming: false,
+    isCompacting: false,
+    isBashRunning: false,
+    pendingMessageCount: 0,
+    queuedMessages: [],
+    tokens: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+    cost: 0,
+  };
+}
+
+describe("SessionController", () => {
+  afterEach(() => {
+    Object.defineProperty(globalThis, "localStorage", { value: undefined, configurable: true });
+  });
+
+  it("recreates missing browser-cached new sessions and moves their draft", async () => {
+    const storage = new MemoryStorage();
+    Object.defineProperty(globalThis, "localStorage", { value: storage, configurable: true });
+    rememberCachedNewSession(oldSession);
+    saveDraft(oldSession.id, "draft text");
+
+    let state: AppState = { ...initialAppState(), selectedWorkspace: workspace, sessions: [markCachedNewSessionInfo(oldSession)] };
+    const urlUpdates: ({ replace?: boolean | undefined } | undefined)[] = [];
+    const socket = new FakeSocket();
+    const api: typeof defaultApi = {
+      ...defaultApi,
+      startSession: () => Promise.resolve(replacementSession),
+      messages: (sessionId) => {
+        if (sessionId === oldSession.id) return Promise.reject(new Error("Session not found"));
+        return Promise.resolve(emptyPage);
+      },
+      status: (sessionId) => Promise.resolve(status(sessionId)),
+    };
+    const controller = new SessionController(
+      () => state,
+      (patch) => { state = { ...state, ...patch }; },
+      (options) => { urlUpdates.push(options); },
+      undefined,
+      { api, socket },
+    );
+
+    await controller.selectSession(markCachedNewSessionInfo(oldSession), { updateUrl: false });
+
+    expect(state.selectedSession?.id).toBe(replacementSession.id);
+    expect(state.sessions.map((session) => session.id)).toEqual([replacementSession.id]);
+    expect(socket.connectedSessionIds).toEqual([oldSession.id, replacementSession.id]);
+    expect(loadDraft(oldSession.id)).toBe("");
+    expect(loadDraft(replacementSession.id)).toBe("draft text");
+    expect(loadCachedNewSessions().map((session) => session.id)).toEqual([replacementSession.id]);
+    expect(urlUpdates).toEqual([{ replace: true }]);
+  });
+});

src/client/src/controllers/sessionController.ts

@@ -1,5 +1,7 @@
 import { api as defaultApi, type CommandResult, type SessionActivity, type SessionInfo, type SessionStatus, type ThinkingLevel } from "../api";
+import { forgetCachedNewSession, isCachedNewSessionInfo, markCachedNewSessionInfo, rememberCachedNewSession, stripCachedNewSessionMarker } from "../cachedNewSessions";
 import { textMessage } from "../chatMessages";
+import { clearDraft, moveDraft } from "../promptDraftStorage";
 import { ChatTranscriptStore } from "../chatTranscriptStore";
 import { isShellInput } from "../inputModes";
 import { SessionSocket, type GlobalSessionEvent, type SessionUiEvent } from "../sessionSocket";
@@ -64,8 +66,10 @@ export class SessionController {
     if (!workspace) return;
     try {
       const session = await this.api.startSession(workspace.path);
-      this.setState({ sessions: [session, ...this.getState().sessions] });
-      await this.selectSession(session);
+      rememberCachedNewSession(session);
+      const cachedSession = markCachedNewSessionInfo(session);
+      this.setState({ sessions: [cachedSession, ...this.getState().sessions] });
+      await this.selectSession(cachedSession);
     } catch (error) {
       this.setState({ error: String(error) });
     }
@@ -116,7 +120,12 @@ export class SessionController {
       this.socket.setHandler((event) => { this.applyEvent(event); });
       if (options?.updateUrl !== false) this.updateUrl();
     } catch (error) {
-      if (seq === this.selectionSeq) this.setState({ error: String(error) });
+      if (seq !== this.selectionSeq || this.getState().selectedSession?.id !== session.id) return;
+      if (isCachedNewSessionInfo(session) && isSessionNotFoundError(error)) {
+        await this.recreateCachedNewSession(session, options);
+        return;
+      }
+      this.setState({ error: String(error) });
     }
   }
 
@@ -145,6 +154,7 @@ export class SessionController {
     if (!session || session.archived === true) return;
     try {
       await this.api.prompt(session.id, text, streamingBehavior);
+      this.markCachedNewSessionPersisted(session);
     } catch (error) {
       this.setState({ error: String(error) });
     }
@@ -156,6 +166,7 @@ export class SessionController {
     this.setState({ messages: [...this.getState().messages, textMessage("user", text)] });
     try {
       await this.api.shell(session.id, text);
+      this.markCachedNewSessionPersisted(session);
     } catch (error) {
       this.setState({ messages: [...this.getState().messages, textMessage("system", String(error))], error: String(error) });
     }
@@ -167,6 +178,7 @@ export class SessionController {
     this.setState({ messages: [...this.getState().messages, textMessage("user", text)] });
     try {
       this.applyCommandResult(await this.api.runCommand(session.id, text));
+      this.markCachedNewSessionPersisted(session);
     } catch (error) {
       this.setState({ messages: [...this.getState().messages, textMessage("system", String(error))], error: String(error) });
     }
@@ -189,6 +201,10 @@ export class SessionController {
 
   async archiveSession(session = this.getState().selectedSession) {
     if (!session) return;
+    if (isCachedNewSessionInfo(session)) {
+      await this.deleteCachedNewSession(session);
+      return;
+    }
     try {
       await this.api.archive(session.id);
       const state = this.getState();
@@ -206,6 +222,24 @@ export class SessionController {
     }
   }
 
+  async deleteCachedNewSession(session = this.getState().selectedSession) {
+    if (!isCachedNewSessionInfo(session)) return;
+    void this.api.stop(session.id).catch(() => {
+      // Best-effort cleanup for browser-cached sessions that may not exist server-side anymore.
+    });
+    forgetCachedNewSession(session.id);
+    clearDraft(session.id);
+    const sessions = this.getState().sessions.filter((candidate) => candidate.id !== session.id);
+    this.setState({ sessions });
+    if (this.getState().selectedSession?.id !== session.id) return;
+    const next = sessions.find((candidate) => candidate.archived !== true) ?? sessions[0];
+    if (next !== undefined) await this.selectSession(next);
+    else {
+      this.clearActiveSession();
+      this.updateUrl();
+    }
+  }
+
   async restoreSession(session = this.getState().selectedSession) {
     if (!session) return;
     try {
@@ -332,6 +366,26 @@ export class SessionController {
     });
   }
 
+  private async recreateCachedNewSession(session: SessionInfo, options?: { updateUrl?: boolean | undefined }): Promise<void> {
+    try {
+      const replacement = await this.api.startSession(session.cwd);
+      rememberCachedNewSession(replacement);
+      moveDraft(session.id, replacement.id);
+      forgetCachedNewSession(session.id);
+      const cachedReplacement = markCachedNewSessionInfo(replacement);
+      this.setState({ sessions: [cachedReplacement, ...this.getState().sessions.filter((candidate) => candidate.id !== session.id)], error: "" });
+      await this.selectSession(cachedReplacement, { updateUrl: false });
+      this.updateUrl(options?.updateUrl === false ? { replace: true } : undefined);
+    } catch (error) {
+      this.setState({ error: String(error) });
+    }
+  }
+
+  private markCachedNewSessionPersisted(session: SessionInfo): void {
+    if (!isCachedNewSessionInfo(session)) return;
+    this.replaceSession(stripCachedNewSessionMarker(session));
+  }
+
   private applyCommandResult(result: CommandResult) {
     if (result.type === "select") {
       this.setState({ commandDialog: result });
@@ -456,3 +510,7 @@ function isHighFrequencyTranscriptEvent(event: SessionUiEvent): boolean {
   return event.type === "assistant.delta" || event.type === "assistant.thinking.delta" || event.type === "shell.chunk";
 }
 
+function isSessionNotFoundError(error: unknown): boolean {
+  return error instanceof Error && error.message.toLowerCase().includes("session not found");
+}
+

src/client/src/controllers/workspaceController.ts

@@ -1,4 +1,5 @@
 import { api, type Project, type Workspace } from "../api";
+import { mergeCachedNewSessions } from "../cachedNewSessions";
 import type { GetState, RouteTarget, SetState, UpdateUrl } from "./types";
 import type { SessionController } from "./sessionController";
 import { InMemoryWorkspaceSelectionMemory, selectPreferredWorkspace, type WorkspaceSelectionMemory } from "./workspaceSelection";
@@ -41,7 +42,7 @@ export class WorkspaceController {
     this.sessions.clearActiveSession();
     this.setState({ selectedWorkspace: workspace, sessions: [], fileTree: [], expandedDirs: {}, selectedFilePath: undefined, selectedFileContent: undefined, fileTreeStale: false, gitStatus: undefined, selectedDiffPath: undefined, selectedDiff: undefined, selectedStagedDiff: undefined, gitStale: false, error: "" });
     try {
-      const sessions = await api.sessions(workspace.path);
+      const sessions = mergeCachedNewSessions(workspace.path, await api.sessions(workspace.path));
       this.setState({ sessions });
       const session = this.sessions.preferredSession(workspace.path, sessions, target?.sessionId);
       if (session) await this.sessions.selectSession(session, { updateUrl: target?.updateUrl });

src/client/src/promptDraftStorage.ts

@@ -0,0 +1,45 @@
+const draftStoragePrefix = "pi-web:prompt-draft:";
+
+function draftStorageKey(sessionId: string): string {
+  return `${draftStoragePrefix}${sessionId}`;
+}
+
+function browserStorage(): Storage | undefined {
+  try {
+    return typeof localStorage === "undefined" ? undefined : localStorage;
+  } catch {
+    return undefined;
+  }
+}
+
+export function loadDraft(sessionId: string, storage = browserStorage()): string {
+  try {
+    return storage?.getItem(draftStorageKey(sessionId)) ?? "";
+  } catch {
+    return "";
+  }
+}
+
+export function saveDraft(sessionId: string, draft: string, storage = browserStorage()): void {
+  try {
+    if (draft) storage?.setItem(draftStorageKey(sessionId), draft);
+    else storage?.removeItem(draftStorageKey(sessionId));
+  } catch {
+    // Ignore localStorage quota/privacy errors.
+  }
+}
+
+export function clearDraft(sessionId: string, storage = browserStorage()): void {
+  try {
+    storage?.removeItem(draftStorageKey(sessionId));
+  } catch {
+    // Ignore localStorage quota/privacy errors.
+  }
+}
+
+export function moveDraft(fromSessionId: string, toSessionId: string, storage = browserStorage()): void {
+  const draft = loadDraft(fromSessionId, storage);
+  if (draft === "") return;
+  saveDraft(toSessionId, draft, storage);
+  clearDraft(fromSessionId, storage);
+}