> ## Documentation Index > Fetch the complete documentation index at: https://developers.arg.ai/llms.txt > Use this file to discover all available pages before exploring further. # Arg SDK overview > One TypeScript SDK for everything that talks to a workspace: apps running inside Arg, published Sites, servers and CI, local development, and the scripts an agent writes. The same `fs`, `chat`, `actions` and resource namespaces run inside an app opened in Arg, in a published Site, on your own server or in CI, against a folder on your machine, and inside the scripts an agent writes during a run. Custom apps import the host-provided `@arg-ai/sdk`, matching Arg's established npm scope. Agent scripts and installed server or hosted clients use `@arg/sdk`. What changes between those places is the **transport** that carries a call and the **permissions** the host grants, never the resource API you write against. ```ts theme={null} import { actions, auth, chat, fs } from "@arg-ai/sdk"; const me = await auth.principal(); const settings = await fs.readJSON<{ title: string }>("./settings.json"); const turn = await chat.start(`Review ${settings.title}`, { openPanel: true }); const catalog = await actions.list({ query: "summarize" }); ``` ## Where it runs | Where your code runs | How to get a client | Credentials | Guide | | ----------------------------------------------------- | ------------------------------------------------------- | ----------------------------------------------------------- | -------------------------------------------- | | An `.html`, `.tsx` or `.jsx` app opened in Arg | `import { fs } from "@arg-ai/sdk"` - nothing to install | None in your code; the viewer's grants in **Permissions** | [Apps inside Arg](/guides/sdk/embedded-apps) | | A published Site opened from Apps in Arg | Bundle `@arg/sdk` into the Site | The signed-in viewer, after they allow **Workspace access** | [Published Sites](/guides/sdk/hosted-sites) | | A Site or hosted frontend outside Arg | `createHostedClient` over your own gateway | A session your app server already owns | [Published Sites](/guides/sdk/hosted-sites) | | A server, a job, CI | `createServerClient` from `@arg/sdk/server` | An [API key](/guides/api-keys) or bearer token | [Servers and CI](/guides/sdk/server) | | A folder on your machine, during development | `arg serve ./my-app` | The CLI's own login, or `--anonymous` | [Local development](/guides/sdk/local) | | A script the agent runs with `run_code` or `run_bash` | `import { fs } from "@arg/sdk"` - preinstalled | A short-lived capability the run injects | [Agent scripts](/guides/sdk/agent-scripts) | Every namespace below is a named export from the SDK entry for its runtime and a property of the default `arg` object. Imported namespaces are lazy: they follow whichever host the code is running in. An explicit client from one of the factories is bound to its transport until you call `dispose()`. | Namespace | What it covers | | -------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------- | | `fs`, `permissions`, `db`, `host` | [Workspace files](/guides/sdk/files): read, write, share, watch, embedded SQLite, open in Arg | | `chat`, `workspace` | [Chats](/guides/sdk/chat): start and continue conversations, list accessible workspaces | | `actions`, `agents` | [Actions and agents](/guides/sdk/actions): the typed capability catalog and agent runs | | `comments`, `notifications`, `integrations`, `automations`, `code`, `sites`, `servers` | [Workspace resources](/guides/sdk/actions#workspace-resources) | | `auth`, `users`, `ui` | Who is calling, who is in the workspace, and the app chrome an app can register | The full method list, every error code and the wire operations are in the [reference](/guides/sdk/reference). ## Install Nothing to install inside Arg: the hosts that run your app resolve `@arg-ai/sdk` themselves. The earlier `@arg/sdk` custom-app spelling remains an alias for saved apps. Everywhere else the unified client is a normal package. ```bash theme={null} npm install @arg/sdk ``` It is pure ESM, has one dependency (the [TypeScript client](/guides/typescript-sdk) it builds on for the server surface, published as `@arg-ai/sdk`) and needs Node 18 or later for the built-in `fetch`. Subpath imports such as `@arg/sdk/fs` and `@arg/sdk/chat` expose the same objects as the root; the runtime factories keep their own entry points: `@arg/sdk/server`, `@arg/sdk/local`, `@arg/sdk/hosted` and `@arg/sdk/gateway`. ## Permissions travel with the host, not the import Importing the SDK grants nothing. Each host decides what a call may do: * Inside Arg, the viewer's **Permissions** menu on the preview: **Workspace access** (read or read and write, over the file's folder or the whole workspace) and **Actions** are separate switches. A denied call fails with `permission_denied` or `disabled`; the SDK never falls back to another credential. * On a server, the API key's own permissions. The backend checks every call; `basePath` is a convenience for relative paths, not an authorization boundary. * In an agent script, the turn's read-only state, its Actions gate and its approval mode. The same code therefore behaves differently in different places by design. A namespace a host cannot serve rejects with `unsupported_capability` rather than pretending; check the [availability table](/guides/sdk/reference#availability-by-host) when a call surprises you. ## How it relates to the other SDKs * [`@arg-ai/sdk`](/guides/typescript-sdk) is also the established server client with the `Run` lifecycle and resilient uploads. Custom apps receive their host-scoped modules under that same package spelling without downloading or receiving server credentials. * `window.arg` is the injected global that HTML apps have always used. It still works. The host-provided `@arg-ai/sdk` gives custom apps the same objects as typed imports. * [`@arg/actions`](/guides/apps/actions-sdk) and [`@arg/ui`](/guides/apps/ui-sdk) stay the React preview facades. `actions` from the app SDK is the same catalog; `ui` is the same app chrome contract without the React components. Read and write workspace files, react to changes, and open chats from an HTML or React app. Drive a workspace from a job with an API key, including conditional writes and Site builds. Start a conversation with the cloud agent, or with Claude Code or Codex on the desktop. Every method, every error code, and which host serves which namespace.