Class AssistantDirectory

examples/assistant/src/server.ts:157–580

// registry wins.

export class AssistantDirectory extends Agent<Env, DirectoryState> {
  initialState: DirectoryState = { chats: [] };

  /**
   * Shared workspace for every chat under this directory. Backed by the
   * directory's own SQLite so all of a user's files live in one place —
   * a `hello.txt` written in chat A shows up verbatim in chat B.
   *
   * Children (`MyAssistant` facets) see this workspace through the
   * `SharedWorkspace` proxy below, which forwards each call to
   * `readFile` / `writeFile` / etc. here. See `SharedWorkspace`.
   *
   * The `onChange` hook fires on every mutation (create/update/delete)
   * regardless of which chat's tool caused it. We rebroadcast to every
   * client connected to this directory — that's every browser tab the
   * user has open — so live UI like the file browser refreshes across
   * chats and tabs without polling. See `_broadcastWorkspaceChange`.
   *
   * Security note: this means any tool running inside any chat has
   * read-write access to every file this user owns. That's the point —
   * a multi-chat assistant should remember what it did in previous
   * chats — but extensions declared with `workspace: "read-write"`
   * inherit the same reach. If you fork this example for a
   * less-trusted extension surface, add gating here.
   */
  workspace = new Workspace({
    sql: this.ctx.storage.sql,
    name: () => this.name,
    onChange: (event) => this._broadcastWorkspaceChange(event)
    // r2: this.env.R2 — uncomment to spill large files to R2.
  });

  /**
   * Fan-out: push workspace change events to every client connected to
   * this directory. Each chat pane's `useAgent` connection to the
   * directory (via `useChats()`) receives these; the client side
   * treats them as signals to refresh workspace-backed UI.
   *
   * Deliberately a best-effort `broadcast` (not `setState`), so file
   * churn doesn't trigger full `DirectoryState` re-broadcasts on every
   * write. Does NOT notify sibling child facets — no tool in this
   * example reacts server-side to another chat's writes. Add a
   * parent → child RPC here if that use case shows up.
   */
  private _broadcastWorkspaceChange(event: WorkspaceChangeEvent): void {
    this.broadcast(JSON.stringify({ type: "workspace-change", event }));
  }

  onStart() {
    this.sql`CREATE TABLE IF NOT EXISTS chat_meta (
      id TEXT PRIMARY KEY,
      title TEXT NOT NULL,
      updated_at INTEGER NOT NULL,
      last_message_preview TEXT
    )`;
    this._refreshState();

    // The directory owns cross-chat scheduled work. Facets can't