feat(filesystem): add create-folder API for workspace picker

Adds a secure endpoint for creating a single subfolder in the current filesystem listing, and wires the non-native directory browser UI to create + enter the new folder.

packages/server/src/api-types.ts

@@ -95,6 +95,26 @@ export interface FileSystemListResponse {
   metadata: FileSystemListingMetadata
 }
 
+export interface FileSystemCreateFolderRequest {
+  /**
+   * Path identifier for the currently browsed directory.
+   * Matches the `path` parameter used for `/api/filesystem`.
+   */
+  parentPath?: string
+  /** Single folder name (no separators). */
+  name: string
+}
+
+export interface FileSystemCreateFolderResponse {
+  /**
+   * Path identifier that can be passed back to `/api/filesystem` to browse the new folder.
+   * Relative for restricted listings, absolute for unrestricted.
+   */
+  path: string
+  /** Absolute folder path on the server host. */
+  absolutePath: string
+}
+
 export const WINDOWS_DRIVES_ROOT = "__drives__"
 
 export interface WorkspaceFileResponse {

packages/server/src/filesystem/browser.ts

@@ -2,6 +2,7 @@ import fs from "fs"
 import os from "os"
 import path from "path"
 import {
+  FileSystemCreateFolderResponse,
   FileSystemEntry,
   FileSystemListResponse,
   FileSystemListingMetadata,
@@ -56,6 +57,30 @@ export class FileSystemBrowser {
     return this.listRestrictedWithMetadata(targetPath, includeFiles)
   }
 
+  createFolder(parentPath: string | undefined, folderName: string): FileSystemCreateFolderResponse {
+    const name = this.normalizeFolderName(folderName)
+
+    if (this.unrestricted) {
+      const resolvedParent = this.resolveUnrestrictedPath(parentPath)
+      if (this.isWindows && resolvedParent === WINDOWS_DRIVES_ROOT) {
+        throw new Error("Cannot create folders at drive root")
+      }
+      this.assertDirectoryExists(resolvedParent)
+      const absolutePath = this.resolveAbsoluteChild(resolvedParent, name)
+      fs.mkdirSync(absolutePath)
+      return { path: absolutePath, absolutePath }
+    }
+
+    const normalizedParent = this.normalizeRelativePath(parentPath)
+    const parentAbsolute = this.toRestrictedAbsolute(normalizedParent)
+    this.assertDirectoryExists(parentAbsolute)
+
+    const relativePath = this.buildRelativePath(normalizedParent, name)
+    const absolutePath = this.toRestrictedAbsolute(relativePath)
+    fs.mkdirSync(absolutePath)
+    return { path: relativePath, absolutePath }
+  }
+
   readFile(relativePath: string): string {
     if (this.unrestricted) {
       throw new Error("readFile is not available in unrestricted mode")
@@ -157,6 +182,41 @@ export class FileSystemBrowser {
     return { entries, metadata }
   }
 
+  private normalizeFolderName(input: string): string {
+    const name = input.trim()
+    if (!name) {
+      throw new Error("Folder name is required")
+    }
+
+    if (name === "." || name === "..") {
+      throw new Error("Invalid folder name")
+    }
+
+    if (name.startsWith("~")) {
+      throw new Error("Invalid folder name")
+    }
+
+    if (name.includes("/") || name.includes("\\")) {
+      throw new Error("Folder name must not include path separators")
+    }
+
+    if (name.includes("\u0000")) {
+      throw new Error("Invalid folder name")
+    }
+
+    return name
+  }
+
+  private assertDirectoryExists(directory: string) {
+    if (!fs.existsSync(directory)) {
+      throw new Error(`Directory does not exist: ${directory}`)
+    }
+    const stats = fs.statSync(directory)
+    if (!stats.isDirectory()) {
+      throw new Error(`Path is not a directory: ${directory}`)
+    }
+  }
+
   private readDirectoryEntries(directory: string, options: DirectoryReadOptions): FileSystemEntry[] {
     const dirents = fs.readdirSync(directory, { withFileTypes: true })
     const results: FileSystemEntry[] = []

packages/server/src/server/routes/filesystem.ts

@@ -11,6 +11,11 @@ const FilesystemQuerySchema = z.object({
   includeFiles: z.coerce.boolean().optional(),
 })
 
+const FilesystemCreateFolderSchema = z.object({
+  parentPath: z.string().optional(),
+  name: z.string(),
+})
+
 export function registerFilesystemRoutes(app: FastifyInstance, deps: RouteDeps) {
   app.get("/api/filesystem", async (request, reply) => {
     const query = FilesystemQuerySchema.parse(request.query ?? {})
@@ -24,4 +29,26 @@ export function registerFilesystemRoutes(app: FastifyInstance, deps: RouteDeps)
       return { error: (error as Error).message }
     }
   })
+
+  app.post("/api/filesystem/folders", async (request, reply) => {
+    const body = FilesystemCreateFolderSchema.parse(request.body ?? {})
+
+    try {
+      const created = deps.fileSystemBrowser.createFolder(body.parentPath, body.name)
+      reply.code(201)
+      return created
+    } catch (error) {
+      const err = error as NodeJS.ErrnoException
+      if (err?.code === "EEXIST") {
+        reply.code(409).type("text/plain").send("Folder already exists")
+        return
+      }
+      if (err?.code === "EACCES" || err?.code === "EPERM") {
+        reply.code(403).type("text/plain").send("Permission denied")
+        return
+      }
+
+      reply.code(400).type("text/plain").send((error as Error).message)
+    }
+  })
 }

packages/ui/src/components/alert-dialog.tsx

@@ -61,13 +61,20 @@ function dismiss(confirmed: boolean, payload?: AlertDialogState | null, promptVa
 
 const AlertDialog: Component = () => {
   let primaryButtonRef: HTMLButtonElement | undefined
+  let promptInputRef: HTMLInputElement | undefined
 
   createEffect(() => {
-    if (alertDialogState()) {
+    const state = alertDialogState()
-      queueMicrotask(() => {
+    if (!state) return
-        primaryButtonRef?.focus()
+
-      })
+    queueMicrotask(() => {
-    }
+      if (state.type === "prompt") {
+        promptInputRef?.focus()
+        promptInputRef?.select()
+        return
+      }
+      primaryButtonRef?.focus()
+    })
   })
 
   return (
@@ -118,25 +125,29 @@ const AlertDialog: Component = () => {
                     </div>
                   </div>
 
-                   <Show when={isPrompt}>
+                    <Show when={isPrompt}>
-                     <div class="mt-4">
+                      <div class="mt-4">
-                       <label class="text-xs font-medium text-muted uppercase tracking-wide">
+                        <label class="text-sm font-medium text-secondary">{payload.inputLabel || "Input"}</label>
-                         {payload.inputLabel || "Arguments"}
+                        <input
-                       </label>
+                          ref={(el) => {
-                       <input
+                            promptInputRef = el
-                         class="modal-search-input mt-2"
+                          }}
-                         value={inputValue()}
+                          class="form-input mt-2"
-                         placeholder={payload.inputPlaceholder || ""}
+                          value={inputValue()}
-                         onInput={(e) => setInputValue(e.currentTarget.value)}
+                          placeholder={payload.inputPlaceholder || ""}
-                         onKeyDown={(e) => {
+                          autocapitalize="off"
-                           if (e.key === "Enter") {
+                          autocorrect="off"
-                             e.preventDefault()
+                          spellcheck={false}
-                             dismiss(true, payload, inputValue())
+                          onInput={(e) => setInputValue(e.currentTarget.value)}
-                           }
+                          onKeyDown={(e) => {
-                         }}
+                            if (e.key === "Enter") {
-                       />
+                              e.preventDefault()
-                     </div>
+                              dismiss(true, payload, inputValue())
-                   </Show>
+                            }
+                          }}
+                        />
+                      </div>
+                    </Show>
 
                    <div class="mt-6 flex justify-end gap-3">
                      {(isConfirm || isPrompt) && (

packages/ui/src/components/directory-browser-dialog.tsx

@@ -1,8 +1,9 @@
 import { Component, Show, For, createSignal, createMemo, createEffect, onCleanup } from "solid-js"
-import { ArrowUpLeft, Folder as FolderIcon, Loader2, X } from "lucide-solid"
+import { ArrowUpLeft, Folder as FolderIcon, FolderPlus, Loader2, X } from "lucide-solid"
 import type { FileSystemEntry, FileSystemListingMetadata } from "../../../server/src/api-types"
 import { WINDOWS_DRIVES_ROOT } from "../../../server/src/api-types"
 import { serverApi } from "../lib/api-client"
+import { showAlertDialog, showPromptDialog } from "../stores/alerts"
 
 function normalizePathKey(input?: string | null) {
   if (!input || input === "." || input === "./") {
@@ -64,6 +65,7 @@ const DirectoryBrowserDialog: Component<DirectoryBrowserDialogProps> = (props) =
   const [rootPath, setRootPath] = createSignal("")
   const [loading, setLoading] = createSignal(false)
   const [error, setError] = createSignal<string | null>(null)
+  const [creatingFolder, setCreatingFolder] = createSignal(false)
   const [directoryChildren, setDirectoryChildren] = createSignal<Map<string, FileSystemEntry[]>>(new Map())
   const [loadingPaths, setLoadingPaths] = createSignal<Set<string>>(new Set())
   const [currentPathKey, setCurrentPathKey] = createSignal<string | null>(null)
@@ -256,6 +258,52 @@ const DirectoryBrowserDialog: Component<DirectoryBrowserDialogProps> = (props) =
     props.onSelect(absolutePath)
   }
 
+  async function handleCreateFolder() {
+    if (creatingFolder()) return
+    const metadata = currentMetadata()
+    if (!metadata || metadata.pathKind === "drives") {
+      return
+    }
+
+    const name =
+      (await showPromptDialog("Create a new folder in the current directory.", {
+        title: "New Folder",
+        inputLabel: "Folder name",
+        inputPlaceholder: "e.g. my-new-project",
+        confirmLabel: "Create",
+        cancelLabel: "Cancel",
+      }))?.trim() ?? ""
+    if (!name) return
+
+    if (name === "." || name === ".." || name.startsWith("~") || name.includes("/") || name.includes("\\")) {
+      showAlertDialog("Please enter a single folder name.", {
+        variant: "warning",
+        detail: "Folder names cannot include slashes, '..', or '~'.",
+      })
+      return
+    }
+
+    setCreatingFolder(true)
+    try {
+      const parentKey = normalizePathKey(metadata.currentPath)
+      metadataCache.delete(parentKey)
+      inFlightRequests.delete(parentKey)
+      setDirectoryChildren((prev) => {
+        const next = new Map(prev)
+        next.delete(parentKey)
+        return next
+      })
+
+      const created = await serverApi.createFileSystemFolder(metadata.currentPath, name)
+      await navigateTo(created.path)
+    } catch (err) {
+      const message = err instanceof Error ? err.message : "Unable to create folder"
+      showAlertDialog(message, { variant: "error", title: "Unable to create folder" })
+    } finally {
+      setCreatingFolder(false)
+    }
+  }
+
   function isPathLoading(path: string) {
     return loadingPaths().has(normalizePathKey(path))
   }
@@ -290,19 +338,32 @@ const DirectoryBrowserDialog: Component<DirectoryBrowserDialogProps> = (props) =
                     <span class="directory-browser-current-label">Current folder</span>
                     <span class="directory-browser-current-path">{currentAbsolutePath()}</span>
                   </div>
-                  <button
+                  <div class="directory-browser-current-actions">
-                    type="button"
+                    <button
-                    class="selector-button selector-button-secondary directory-browser-select directory-browser-current-select"
+                      type="button"
-                    disabled={!canSelectCurrent()}
+                      class="selector-button selector-button-secondary directory-browser-select directory-browser-current-select"
-                    onClick={() => {
+                      disabled={!canSelectCurrent() || creatingFolder()}
-                      const absolute = currentAbsolutePath()
+                      onClick={() => {
-                      if (absolute) {
+                        const absolute = currentAbsolutePath()
-                        props.onSelect(absolute)
+                        if (absolute) {
-                      }
+                          props.onSelect(absolute)
-                    }}
+                        }
-                  >
+                      }}
-                    Select Current
+                    >
-                  </button>
+                      Select Current
+                    </button>
+                    <button
+                      type="button"
+                      class="selector-button selector-button-secondary directory-browser-select"
+                      disabled={!canSelectCurrent() || creatingFolder()}
+                      onClick={() => void handleCreateFolder()}
+                    >
+                      <span class="inline-flex items-center gap-2">
+                        <FolderPlus class="w-4 h-4" />
+                        {creatingFolder() ? "Creating…" : "New Folder"}
+                      </span>
+                    </button>
+                  </div>
                 </div>
               </Show>
               <Show

packages/ui/src/components/folder-selection-view.tsx

@@ -57,6 +57,19 @@ const FolderSelectionView: Component<FolderSelectionViewProps> = (props) => {
 
 
   function handleKeyDown(e: KeyboardEvent) {
+    let activeElement: HTMLElement | null = null
+    if (typeof document !== "undefined") {
+      activeElement = document.activeElement as HTMLElement | null
+    }
+    const insideModal = activeElement?.closest(".modal-surface") || activeElement?.closest("[role='dialog']")
+    const isEditingField =
+      activeElement &&
+      (["INPUT", "TEXTAREA", "SELECT"].includes(activeElement.tagName) || activeElement.isContentEditable || Boolean(insideModal))
+
+    if (isEditingField) {
+      return
+    }
+
     const normalizedKey = e.key.toLowerCase()
     const isBrowseShortcut = (e.metaKey || e.ctrlKey) && !e.shiftKey && normalizedKey === "n"
     const blockedKeys = [

packages/ui/src/lib/api-client.ts

@@ -8,6 +8,7 @@ import type {
   BinaryUpdateRequest,
   BinaryValidationResult,
   FileSystemEntry,
+  FileSystemCreateFolderResponse,
   FileSystemListResponse,
   InstanceData,
   ServerMeta,
@@ -224,6 +225,13 @@ export const serverApi = {
     const query = params.toString()
     return request<FileSystemListResponse>(query ? `/api/filesystem?${query}` : "/api/filesystem")
   },
+
+  createFileSystemFolder(parentPath: string | undefined, name: string): Promise<FileSystemCreateFolderResponse> {
+    return request<FileSystemCreateFolderResponse>("/api/filesystem/folders", {
+      method: "POST",
+      body: JSON.stringify({ parentPath, name }),
+    })
+  },
   readInstanceData(id: string): Promise<InstanceData> {
     return request<InstanceData>(`/api/storage/instances/${encodeURIComponent(id)}`)
   },

packages/ui/src/styles/components/directory-browser.css

@@ -81,6 +81,14 @@
   width: auto;
 }
 
+.directory-browser-current-actions {
+  display: flex;
+  align-items: center;
+  gap: var(--space-sm);
+  flex-wrap: wrap;
+  justify-content: flex-end;
+}
+
 .directory-browser-close {
 
   display: inline-flex;

packages/ui/src/styles/utilities.css

@@ -103,6 +103,25 @@
   box-shadow: 0 0 0 2px var(--accent-primary);
 }
 
+/* Form controls */
+.form-input {
+  @apply w-full px-3 py-2 text-sm;
+  background-color: var(--surface-base);
+  border: 1px solid var(--border-base);
+  border-radius: var(--radius-md);
+  color: var(--text-primary);
+}
+
+.form-input::placeholder {
+  color: var(--text-muted);
+}
+
+.form-input:focus {
+  outline: none;
+  border-color: transparent;
+  box-shadow: 0 0 0 2px var(--accent-primary);
+}
+
 /* Shared animations */
 @keyframes pulse {
   0%, 100% { opacity: 1; }