Moldable App Development
This skill provides comprehensive knowledge for building and modifying apps within the Moldable desktop application.
Quick Reference
| Resource | Path |
|---|---|
| App source code | ~/.moldable/shared/apps/{app-id}/ |
| App runtime data | ~/.moldable/workspaces/{workspace-id}/apps/{app-id}/data/ |
| Workspace config | ~/.moldable/workspaces/{workspace-id}/config.json |
| MCP config | ~/.moldable/shared/config/mcp.json |
| Skills | ~/.moldable/shared/skills/{repo}/{skill}/ |
| Environment | ~/.moldable/shared/.env |
Default Tech Stack
- Framework: Vite + Hono + React 19 + TypeScript
- Styling: Tailwind CSS 4 + shadcn/ui (semantic colors only)
- State: TanStack Query v5
- Storage: Filesystem via
@moldable-ai/storage - Dev Reloading: Vite client HMR via Portless-aware
MOLDABLE_APP_URL; Hono server reloads viatsx watch - Package Manager: pnpm
Creating Apps
ALWAYS use the scaffoldApp tool — never create app files manually.
scaffoldApp({
appId: "expense-tracker", // lowercase, hyphens only
name: "Expense Tracker", // Display name
icon: "💰", // Emoji icon
description: "Track expenses and generate reports",
widgetSize: "medium", // small, medium, or large
extraDependencies: {
// Optional npm packages
zod: "^3.0.0",
},
});After scaffolding, customize:
src/client/app.tsx— Main app viewsrc/client/widget.tsx— Widget viewsrc/server/app.tsorsrc/server/routes/— Hono API routessrc/client/components/orsrc/components/— React components
Detailed References
Read these for in-depth guidance:
Core Concepts
- references/app-lifecycle.md — Creating, starting, managing, and deleting apps
- references/app-scaffold.md — Required files, lint rules, templates for new apps
- references/workspaces.md — Workspace system, data isolation, environment layering
- references/configuration.md — moldable.json, config.json, environment variables
Implementation Patterns
- references/ui.md — @moldable-ai/ui components, shadcn/ui, themes, rich text editor, Cmd+K app commands
- references/storage-patterns.md — Filesystem storage, React Query, workspace-aware APIs
- references/desktop-apis.md — postMessage APIs (open-url, show-in-folder, set-chat-input, save-file)
- references/app-to-app-communication.md — App-to-app RPC, capability manifests, workspace-scoped grants, Calendar-owned OAuth/data access
- references/skills-mcps.md — Skills library, MCP configuration, custom MCP servers
Essential Patterns
1. UI Components (@moldable-ai/ui)
Always use @moldable-ai/ui for all UI work. It includes shadcn/ui components, theme support, and a rich text editor.
// Import components from @moldable-ai/ui (NOT from shadcn directly)
import {
Button,
Card,
Input,
Dialog,
Select,
Tabs,
ThemeProvider,
WorkspaceProvider,
useTheme,
Markdown,
CodeBlock,
WidgetLayout,
downloadFile,
sendToMoldable,
} from "@moldable-ai/ui";
// For rich text editing
import { MarkdownEditor } from "@moldable-ai/editor";Use semantic colors only:
// ✅ Correct
<div className="bg-background text-foreground border-border" />
<Button className="bg-primary text-primary-foreground" />
// ❌ Wrong - raw colors don't adapt to theme
<div className="bg-white text-gray-900" />See references/ui.md for complete component list and usage.
2. Workspace-Aware Storage
All apps must isolate data per workspace:
// Client - use workspaceId in query keys
const { workspaceId, fetchWithWorkspace } = useWorkspace();
const { data } = useQuery({
queryKey: ["items", workspaceId], // ← Include workspace!
queryFn: () => fetchWithWorkspace("/api/items").then((r) => r.json()),
});
// Server - extract workspace from request
import { getWorkspaceFromRequest, getAppDataDir } from "@moldable-ai/storage";
export async function GET(request: Request) {
const workspaceId = getWorkspaceFromRequest(request);
const dataDir = getAppDataDir(workspaceId);
// Read/write files in dataDir
}3. Desktop Integration
Apps communicate with Moldable desktop via postMessage:
// Open external URL
window.parent.postMessage(
{ type: "moldable:open-url", url: "https://..." },
"*",
);
// Show file in Finder
window.parent.postMessage(
{ type: "moldable:show-in-folder", path: "/path/to/file" },
"*",
);
// Pre-populate chat input
window.parent.postMessage(
{ type: "moldable:set-chat-input", text: "Help me..." },
"*",
);
// Provide context to AI
window.parent.postMessage(
{
type: "moldable:set-chat-instructions",
text: "User is viewing meeting #123...",
},
"*",
);4. Layout Setup
Required providers for Moldable apps:
// src/client/main.tsx
import { StrictMode } from "react";
import { createRoot } from "react-dom/client";
import { ThemeProvider, WorkspaceProvider } from "@moldable-ai/ui";
import { App } from "./app";
import { QueryProvider } from "./query-provider";
createRoot(document.getElementById("root")!).render(
<StrictMode>
<ThemeProvider>
<WorkspaceProvider>
<QueryProvider>
<App />
</QueryProvider>
</WorkspaceProvider>
</ThemeProvider>
</StrictMode>,
);5. Adding Dependencies
Use sandbox: false for package manager commands:
await runCommand({
command: "cd ~/.moldable/shared/apps/my-app && pnpm add zod",
sandbox: false, // Required for network access
});App Management Tools
| Tool | Purpose | Reversible |
|---|---|---|
scaffoldApp | Create new app | — |
getAppInfo | Check which workspaces use an app | — |
unregisterApp | Remove from current workspace only | ✅ Re-add later |
deleteAppData | Delete app's data (keep installed) | ❌ Data lost |
deleteApp | Permanently delete from ALL workspaces | ❌ Everything lost |
File Structure
~/.moldable/
├── shared/
│ ├── apps/{app-id}/ # App source code
│ │ ├── moldable.json # App manifest
│ │ ├── package.json
│ │ └── src/
│ ├── skills/{repo}/{skill}/ # Skills library
│ ├── mcps/{mcp-name}/ # Custom MCP servers
│ └── config/mcp.json # Shared MCP config
│
└── workspaces/{workspace-id}/
├── config.json # Registered apps
├── .env # Workspace env overrides
├── apps/{app-id}/data/ # App runtime data
└── conversations/ # Chat historyCommon Mistakes to Avoid
- ❌ Creating apps manually — Always use
scaffoldApp - ❌ Using localStorage — Use filesystem storage
- ❌ Forgetting workspaceId — Include in query keys and API calls
- ❌ Hardcoding paths — Use
getAppDataDir()for portability - ❌ Using raw colors — Use shadcn semantic colors (
bg-background, notbg-gray-100) - ❌ Running pnpm with sandbox — Set
sandbox: falsefor network access
Study Existing Apps
For complex features, reference apps in ~/.moldable/shared/apps/:
- scribo — Translation journal with language selection
- meetings — Audio recording with real-time transcription
- calendar — Google Calendar integration with OAuth
These demonstrate data fetching, storage patterns, API routes, and UI components.