Add desktop runtime API and SDK support

docs/cli.mdx

@@ -37,6 +37,36 @@ Notes:
 - Set `SANDBOX_AGENT_LOG_STDOUT=1` to force stdout/stderr logging.
 - Use `SANDBOX_AGENT_LOG_DIR` to override log directory.
 
+## install
+
+Install first-party runtime dependencies.
+
+### install desktop
+
+Install the Linux desktop runtime packages required by `/v1/desktop/*`.
+
+```bash
+sandbox-agent install desktop [OPTIONS]
+```
+
+| Option | Description |
+|--------|-------------|
+| `--yes` | Skip the confirmation prompt |
+| `--print-only` | Print the package-manager command without executing it |
+| `--package-manager <apt\|dnf\|apk>` | Override package-manager detection |
+| `--no-fonts` | Skip the default DejaVu font package |
+
+```bash
+sandbox-agent install desktop --yes
+sandbox-agent install desktop --print-only
+```
+
+Notes:
+
+- Supported on Linux only.
+- The command detects `apt`, `dnf`, or `apk`.
+- If the host is not already running as root, the command requires `sudo`.
+
 ## install-agent
 
 Install or reinstall a single agent.

docs/deploy/docker.mdx

@@ -21,6 +21,27 @@ docker run --rm -p 3000:3000 \
     sandbox-agent server --no-token --host 0.0.0.0 --port 3000"
 ```
 
+If you also want the desktop API inside the container, install desktop dependencies before starting the server:
+
+```bash
+docker run --rm -p 3000:3000 \
+  -e ANTHROPIC_API_KEY="$ANTHROPIC_API_KEY" \
+  -e OPENAI_API_KEY="$OPENAI_API_KEY" \
+  node:22-bookworm-slim sh -c "\
+    apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y curl ca-certificates bash libstdc++6 && \
+    rm -rf /var/lib/apt/lists/* && \
+    curl -fsSL https://releases.rivet.dev/sandbox-agent/0.3.x/install.sh | sh && \
+    sandbox-agent install desktop --yes && \
+    sandbox-agent server --no-token --host 0.0.0.0 --port 3000"
+```
+
+In a Dockerfile:
+
+```dockerfile
+RUN sandbox-agent install desktop --yes
+```
+
 ## TypeScript with dockerode
 
 ```typescript

docs/inspector.mdx

@@ -34,6 +34,7 @@ console.log(url);
 - Event JSON inspector
 - Prompt testing
 - Request/response debugging
+- Desktop panel for status, remediation, start/stop, and screenshot refresh
 - Process management (create, stop, kill, delete, view logs)
 - Interactive PTY terminal for tty processes
 - One-shot command execution
@@ -49,3 +50,16 @@ console.log(url);
 The Inspector includes an embedded Ghostty-based terminal for interactive tty
 processes. The UI uses the SDK's high-level `connectProcessTerminal(...)`
 wrapper via the shared `@sandbox-agent/react` `ProcessTerminal` component.
+
+## Desktop panel
+
+The `Desktop` panel shows the current desktop runtime state, missing dependencies,
+the suggested install command, last error details, process/log paths, and the
+latest captured screenshot.
+
+Use it to:
+
+- Check whether desktop dependencies are installed
+- Start or stop the managed desktop runtime
+- Refresh desktop status
+- Capture a fresh screenshot on demand

docs/quickstart.mdx

@@ -224,6 +224,16 @@ icon: "rocket"
     If agents are not installed up front, they are lazily installed when creating a session.
   </Step>
 
+  <Step title="Install desktop dependencies (optional, Linux only)">
+    If you want to use `/v1/desktop/*`, install the desktop runtime packages first:
+
+    ```bash
+    sandbox-agent install desktop --yes
+    ```
+
+    Then use `GET /v1/desktop/status` or `sdk.getDesktopStatus()` to verify the runtime is ready before calling desktop screenshot or input APIs.
+  </Step>
+
   <Step title="Create a session">
     ```typescript
     import { SandboxAgent } from "sandbox-agent";

docs/sdk-overview.mdx

@@ -177,6 +177,44 @@ const writeResult = await sdk.writeFsFile({ path: "./hello.txt" }, "hello");
 console.log(health.status, agents.agents.length, entries.length, writeResult.path);
 ```
 
+## Desktop API
+
+The SDK also wraps the desktop host/runtime HTTP API.
+
+Install desktop dependencies first on Linux hosts:
+
+```bash
+sandbox-agent install desktop --yes
+```
+
+Then query status, surface remediation if needed, and start the runtime:
+
+```ts
+const status = await sdk.getDesktopStatus();
+
+if (status.state === "install_required") {
+  console.log(status.installCommand);
+}
+
+const started = await sdk.startDesktop({
+  width: 1440,
+  height: 900,
+  dpi: 96,
+});
+
+const screenshot = await sdk.takeDesktopScreenshot();
+const displayInfo = await sdk.getDesktopDisplayInfo();
+
+await sdk.moveDesktopMouse({ x: 400, y: 300 });
+await sdk.clickDesktop({ x: 400, y: 300, button: "left", clickCount: 1 });
+await sdk.typeDesktopText({ text: "hello world", delayMs: 10 });
+await sdk.pressDesktopKey({ key: "ctrl+l" });
+
+await sdk.stopDesktop();
+```
+
+Screenshot helpers return `Uint8Array` PNG bytes. The SDK does not attempt to install OS packages remotely; callers should surface `missingDependencies` and `installCommand` from `getDesktopStatus()`.
+
 ## Error handling
 
 ```ts