feat: add list_folders_in_directory and read_file command handlers (#1489)

Co-authored-by: Letta Code <noreply@letta.com>

src/types/protocol_v2.ts

@@ -395,6 +395,20 @@ export interface SearchFilesCommand {
   max_results?: number;
 }
 
+export interface ListFoldersInDirectoryCommand {
+  type: "list_folders_in_directory";
+  /** Absolute path to list folders in. */
+  path: string;
+}
+
+export interface ReadFileCommand {
+  type: "read_file";
+  /** Absolute path to the file to read. */
+  path: string;
+  /** Echoed back in the response for request correlation. */
+  request_id: string;
+}
+
 export type WsProtocolCommand =
   | InputCommand
   | ChangeDeviceStateCommand
@@ -404,7 +418,9 @@ export type WsProtocolCommand =
   | TerminalInputCommand
   | TerminalResizeCommand
   | TerminalKillCommand
-  | SearchFilesCommand;
+  | SearchFilesCommand
+  | ListFoldersInDirectoryCommand
+  | ReadFileCommand;
 
 export type WsProtocolMessage =
   | DeviceStatusUpdateMessage

src/websocket/listener/client.ts

@@ -61,7 +61,12 @@ import {
   loadPersistedPermissionModeMap,
   setConversationPermissionModeState,
 } from "./permissionMode";
-import { isSearchFilesCommand, parseServerMessage } from "./protocol-inbound";
+import {
+  isListFoldersCommand,
+  isReadFileCommand,
+  isSearchFilesCommand,
+  parseServerMessage,
+} from "./protocol-inbound";
 import {
   buildDeviceStatus,
   buildLoopStatus,
@@ -1016,6 +1021,73 @@ async function connectWithRetry(
       return;
     }
 
+    // ── Folder listing (no runtime scope required) ────────────────────
+    if (isListFoldersCommand(parsed)) {
+      void (async () => {
+        try {
+          const { readdir } = await import("node:fs/promises");
+          const entries = await readdir(parsed.path, { withFileTypes: true });
+          const folders = entries
+            .filter((e) => e.isDirectory())
+            .map((e) => e.name)
+            .sort();
+          socket.send(
+            JSON.stringify({
+              type: "list_folders_in_directory_response",
+              path: parsed.path,
+              folders,
+              hasMore: false,
+              success: true,
+            }),
+          );
+        } catch (err) {
+          socket.send(
+            JSON.stringify({
+              type: "list_folders_in_directory_response",
+              path: parsed.path,
+              folders: [],
+              hasMore: false,
+              success: false,
+              error:
+                err instanceof Error ? err.message : "Failed to list folders",
+            }),
+          );
+        }
+      })();
+      return;
+    }
+
+    // ── File reading (no runtime scope required) ─────────────────────
+    if (isReadFileCommand(parsed)) {
+      void (async () => {
+        try {
+          const { readFile } = await import("node:fs/promises");
+          const content = await readFile(parsed.path, "utf-8");
+          socket.send(
+            JSON.stringify({
+              type: "read_file_response",
+              request_id: parsed.request_id,
+              path: parsed.path,
+              content,
+              success: true,
+            }),
+          );
+        } catch (err) {
+          socket.send(
+            JSON.stringify({
+              type: "read_file_response",
+              request_id: parsed.request_id,
+              path: parsed.path,
+              content: null,
+              success: false,
+              error: err instanceof Error ? err.message : "Failed to read file",
+            }),
+          );
+        }
+      })();
+      return;
+    }
+
     // ── Terminal commands (no runtime scope required) ──────────────────
     if (parsed.type === "terminal_spawn") {
       handleTerminalSpawn(

src/websocket/listener/protocol-inbound.ts

@@ -3,6 +3,8 @@ import type {
   AbortMessageCommand,
   ChangeDeviceStateCommand,
   InputCommand,
+  ListFoldersInDirectoryCommand,
+  ReadFileCommand,
   RuntimeScope,
   SearchFilesCommand,
   SyncCommand,
@@ -253,6 +255,24 @@ export function isSearchFilesCommand(
   );
 }
 
+export function isListFoldersCommand(
+  value: unknown,
+): value is ListFoldersInDirectoryCommand {
+  if (!value || typeof value !== "object") return false;
+  const c = value as { type?: unknown; path?: unknown };
+  return c.type === "list_folders_in_directory" && typeof c.path === "string";
+}
+
+export function isReadFileCommand(value: unknown): value is ReadFileCommand {
+  if (!value || typeof value !== "object") return false;
+  const c = value as { type?: unknown; path?: unknown; request_id?: unknown };
+  return (
+    c.type === "read_file" &&
+    typeof c.path === "string" &&
+    typeof c.request_id === "string"
+  );
+}
+
 export function parseServerMessage(
   data: WebSocket.RawData,
 ): ParsedServerMessage | null {
@@ -268,7 +288,9 @@ export function parseServerMessage(
       isTerminalInputCommand(parsed) ||
       isTerminalResizeCommand(parsed) ||
       isTerminalKillCommand(parsed) ||
-      isSearchFilesCommand(parsed)
+      isSearchFilesCommand(parsed) ||
+      isListFoldersCommand(parsed) ||
+      isReadFileCommand(parsed)
     ) {
       return parsed as WsProtocolCommand;
     }