diff --git a/README.md b/README.md
new file mode 100644
index 0000000..08296b3
--- /dev/null
+++ b/README.md
@@ -0,0 +1,189 @@
+# bricks-mp
+
+Kotlin Multiplatform / Compose runtime for rendering WebBricks UI descriptions.
+
+The library is intentionally product-neutral. Application-specific clients, login flows and entry UI loading should live in the application project, not in the `com.bricks.mp` library packages.
+
+## WebBricks backend request parameters
+
+`BricksHttp` automatically appends the WebBricks runtime parameters to `.ui` and `.dspy` requests:
+
+- `_webbricks_`
+- `_width`
+- `_height`
+- `_is_mobile`
+- `_lang`
+
+Update viewport/language metadata from the host application when the window or device changes:
+
+```kotlin
+http.updateRequestContext(
+    width = windowWidthPx,
+    height = windowHeightPx,
+    isMobile = false,
+    lang = Locale.getDefault().toLanguageTag()
+)
+```
+
+## Generic HTTP handling
+
+`BricksHttp` does not silently parse error responses as widgets. It throws `BricksHttpException` for HTTP errors and redirects. `ActionDispatcher` provides generic UI behavior:
+
+- `403`: load `/rbac/user/login.ui` and show it through `onDialog`.
+- `401`: show the response body through `onMessage`.
+- `3xx` including `301`: read the `Location` header and load the redirected UI.
+
+Applications can override the login UI path:
+
+```kotlin
+actionDispatcher.loginUiPath = "/my/login.ui"
+```
+
+## 新建 Sage 应用主程序示例
+
+下面代码是新建 Sage 桌面应用时可放到应用工程里的主程序示例。它演示如何用通用 `BricksHttp` 完成 Sage 的 cookie/session 登录、加载 `center.ui`，并接入 `ActionDispatcher`。这不是 bricks-mp 库包内容。
+
+```kotlin
+package com.example.sage
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.*
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.Window
+import androidx.compose.ui.window.application
+import com.bricks.mp.actions.ActionDispatcher
+import com.bricks.mp.core.BricksContext
+import com.bricks.mp.core.BricksHttp
+import com.bricks.mp.core.BricksWidget
+import com.bricks.mp.core.RenderWidget
+import kotlinx.coroutines.launch
+import kotlinx.serialization.json.jsonPrimitive
+
+private const val DEFAULT_SAGE_BASE_URL = "https://ai.atvoe.com"
+
+fun main() = application {
+    val context = remember { BricksContext().apply { baseUrl = DEFAULT_SAGE_BASE_URL } }
+    val http = remember { BricksHttp(context) }
+    val scope = rememberCoroutineScope()
+
+    var loggedIn by remember { mutableStateOf(false) }
+    var rootWidget by remember { mutableStateOf<BricksWidget?>(null) }
+    var dialogWidget by remember { mutableStateOf<BricksWidget?>(null) }
+    var message by remember { mutableStateOf<String?>(null) }
+
+    Window(
+        onCloseRequest = {
+            http.close()
+            exitApplication()
+        },
+        title = if (loggedIn) "Sage" else "Sage - Login"
+    ) {
+        MaterialTheme {
+            if (!loggedIn) {
+                SageLoginScreen(
+                    baseUrl = context.baseUrl,
+                    onBaseUrlChange = { context.baseUrl = it },
+                    onLogin = { username, password ->
+                        scope.launch {
+                            runCatching {
+                                // Sage requires an initial request so the server can issue a session cookie.
+                                http.getText(context.baseUrl.trimEnd('/') + "/")
+
+                                val loginJson = http.getJson(
+                                    url = context.entireUrl("/rbac/user/up_login.dspy"),
+                                    params = mapOf(
+                                        "username" to username,
+                                        "password" to password
+                                    )
+                                )
+
+                                val widgetType = loginJson["widgettype"]?.jsonPrimitive?.content
+                                require(widgetType == "Message" || widgetType == "UiMessage") {
+                                    loginJson["options"]?.toString() ?: "登录失败"
+                                }
+
+                                http.fetchUi("center.ui")
+                            }.onSuccess { widget ->
+                                rootWidget = widget
+                                context.setCurrentWidget(widget)
+                                loggedIn = true
+                            }.onFailure { error ->
+                                message = error.message ?: "登录失败"
+                            }
+                        }
+                    }
+                )
+            } else {
+                val actionDispatcher = remember {
+                    ActionDispatcher(context = context, http = http, scope = scope).apply {
+                        loginUiPath = "/rbac/user/login.ui"
+                        onWidgetLoaded = { widget -> context.setCurrentWidget(widget) }
+                        onDialog = { widget, show -> dialogWidget = if (show) widget else null }
+                        onMessage = { title, body, _ -> message = "$title\n$body" }
+                    }
+                }
+                val currentWidget by context.currentWidget.collectAsState()
+                RenderWidget(
+                    widget = currentWidget ?: rootWidget ?: return@MaterialTheme,
+                    actionDispatcher = actionDispatcher,
+                    modifier = Modifier.fillMaxSize()
+                )
+
+                dialogWidget?.let { widget ->
+                    AlertDialog(
+                        onDismissRequest = { dialogWidget = null },
+                        text = { RenderWidget(widget, actionDispatcher) },
+                        confirmButton = {
+                            TextButton(onClick = { dialogWidget = null }) { Text("Close") }
+                        }
+                    )
+                }
+            }
+
+            message?.let { text ->
+                AlertDialog(
+                    onDismissRequest = { message = null },
+                    title = { Text("Sage") },
+                    text = { Text(text) },
+                    confirmButton = { TextButton(onClick = { message = null }) { Text("OK") } }
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun SageLoginScreen(
+    baseUrl: String,
+    onBaseUrlChange: (String) -> Unit,
+    onLogin: (username: String, password: String) -> Unit
+) {
+    var username by remember { mutableStateOf("") }
+    var password by remember { mutableStateOf("") }
+
+    Box(Modifier.fillMaxSize().padding(32.dp)) {
+        Column {
+            Text("Sage")
+            OutlinedTextField(baseUrl, onBaseUrlChange, label = { Text("服务器地址") })
+            OutlinedTextField(username, { username = it }, label = { Text("用户名") })
+            OutlinedTextField(password, { password = it }, label = { Text("密码") })
+            Button(
+                onClick = { onLogin(username, password) },
+                enabled = username.isNotBlank() && password.isNotBlank()
+            ) {
+                Text("登录")
+            }
+        }
+    }
+}
+```
diff --git a/shared/src/commonMain/kotlin/com/bricks/mp/actions/ActionDispatcher.kt b/shared/src/commonMain/kotlin/com/bricks/mp/actions/ActionDispatcher.kt
index bc5f06d..8084a54 100644
--- a/shared/src/commonMain/kotlin/com/bricks/mp/actions/ActionDispatcher.kt
+++ b/shared/src/commonMain/kotlin/com/bricks/mp/actions/ActionDispatcher.kt
@@ -1,19 +1,25 @@
 package com.bricks.mp.actions
 
 import com.bricks.mp.core.*
-import com.bricks.mp.sage.SageClient
+import io.ktor.http.URLBuilder
+import io.ktor.http.takeFrom
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch
-import kotlinx.serialization.json.*
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.contentOrNull
 
 /**
  * 事件分发器 - 处理 actiontype: urlwidget/method/script/registerfunction/event
- * 支持回调机制以更新 UI 状态
+ * 支持回调机制以更新 UI 状态。
+ *
+ * HTTP 错误处理保持通用：
+ * - 403：加载 /rbac/user/login.ui 并通过 onDialog 弹出；
+ * - 401：通过 onMessage 显示服务端错误内容；
+ * - 3xx：读取 Location 并按页面跳转加载目标 UI。
  */
 class ActionDispatcher(
     private val context: BricksContext,
     private val http: BricksHttp,
-    private val sageClient: SageClient?,
     private val scope: CoroutineScope
 ) {
 
@@ -28,6 +34,11 @@ class ActionDispatcher(
     // 回调: 弹出/关闭对话框
     var onDialog: ((widget: BricksWidget?, show: Boolean) -> Unit)? = null
 
+    /**
+     * 403 时默认加载的登录 UI。应用可以改成自己的登录页路径。
+     */
+    var loginUiPath: String = "/rbac/user/login.ui"
+
     /**
      * 注册回调函数 (registerfunction)
      */
@@ -54,49 +65,86 @@ class ActionDispatcher(
             if (it is JsonPrimitive) it.contentOrNull else null
         } ?: bind.url ?: return
 
-        val method = bind.options["method"]?.let {
-            if (it is JsonPrimitive) it.contentOrNull?.uppercase() else null
-        } ?: "GET"
-
         scope.launch {
-            try {
-                val fullUrl = resolveUrl(url)
+            loadWidget(url, showAsDialog = false)
+        }
+    }
 
-                val widget = if (sageClient != null) {
-                    sageClient.fetchUi(fullUrl).getOrNull()
-                        ?: httpFetchWidget(fullUrl)
-                } else {
-                    httpFetchWidget(fullUrl)
-                }
-
-                if (widget != null) {
-                    // Resolve entire_url templates
-                    onWidgetLoaded?.invoke(widget)
-                    println("[Bricks] urlwidget loaded: $fullUrl")
-                } else {
-                    onMessage?.invoke("Error", "Failed to load: $url", true)
-                }
-            } catch (e: Exception) {
-                println("[Bricks] urlwidget error: ${e.message}")
-                onMessage?.invoke("Error", "Failed to load: ${e.message}", true)
+    private suspend fun loadWidget(url: String, showAsDialog: Boolean, redirectDepth: Int = 0) {
+        val fullUrl = resolveUrl(url)
+        try {
+            val widget = http.fetchUi(fullUrl, authToken = context.authToken)
+            if (showAsDialog) {
+                onDialog?.invoke(widget, true)
+            } else {
+                onWidgetLoaded?.invoke(widget)
             }
+            println("[Bricks] urlwidget loaded: $fullUrl")
+        } catch (e: BricksHttpException) {
+            handleHttpException(e, fullUrl, showAsDialog, redirectDepth)
+        } catch (e: Exception) {
+            println("[Bricks] urlwidget error: ${e.message}")
+            onMessage?.invoke("Error", "Failed to load: ${e.message}", true)
         }
     }
 
-    private suspend fun httpFetchWidget(url: String): BricksWidget? {
-        return try {
-            val text = http.getText(url, authToken = context.authToken)
-            BricksParser.parse(text)
-        } catch (e: Exception) {
-            null
+    private suspend fun handleHttpException(
+        error: BricksHttpException,
+        requestUrl: String,
+        showAsDialog: Boolean,
+        redirectDepth: Int
+    ) {
+        when (error.statusCode) {
+            403 -> showLoginDialog(error)
+            401 -> onMessage?.invoke("Unauthorized", error.displayBody(), true)
+            in 300..399 -> {
+                val location = error.location
+                if (location.isNullOrBlank()) {
+                    onMessage?.invoke("Redirect", "HTTP ${error.statusCode} without Location", true)
+                    return
+                }
+                if (redirectDepth >= MAX_REDIRECTS) {
+                    onMessage?.invoke("Redirect", "Too many redirects: $location", true)
+                    return
+                }
+                val nextUrl = resolveRedirectUrl(requestUrl, location)
+                println("[Bricks] redirect ${error.statusCode}: $requestUrl -> $nextUrl")
+                loadWidget(nextUrl, showAsDialog, redirectDepth + 1)
+            }
+            else -> onMessage?.invoke("HTTP ${error.statusCode}", error.displayBody(), true)
         }
     }
 
+    private suspend fun showLoginDialog(error: BricksHttpException) {
+        try {
+            val loginWidget = http.fetchUi(resolveUrl(loginUiPath), authToken = context.authToken)
+            onDialog?.invoke(loginWidget, true)
+            println("[Bricks] HTTP 403: login dialog loaded from $loginUiPath")
+        } catch (loginError: Exception) {
+            val message = "${error.displayBody()}\nLogin UI load failed: ${loginError.message}"
+            onMessage?.invoke("Forbidden", message, true)
+        }
+    }
+
+    private fun BricksHttpException.displayBody(): String =
+        responseBody.take(1000).ifBlank { message ?: "HTTP $statusCode" }
+
     private fun resolveUrl(url: String): String {
-        if (url.startsWith("http")) return url
+        if (url.startsWith("http://") || url.startsWith("https://")) return url
         return context.entireUrl(url)
     }
 
+    private fun resolveRedirectUrl(requestUrl: String, location: String): String {
+        if (location.startsWith("http://") || location.startsWith("https://")) return location
+        val base = URLBuilder().takeFrom(requestUrl)
+        return if (location.startsWith("/")) {
+            "${base.protocol.name}://${base.host}${if (base.port == base.protocol.defaultPort) "" else ":${base.port}"}$location"
+        } else {
+            val parentPath = base.encodedPath.substringBeforeLast('/', missingDelimiterValue = "")
+            "${base.protocol.name}://${base.host}${if (base.port == base.protocol.defaultPort) "" else ":${base.port}"}$parentPath/$location"
+        }
+    }
+
     private fun handleMethod(bind: BricksBind) {
         val methodName = bind.methodname ?: bind.target ?: return
 
@@ -153,4 +201,8 @@ class ActionDispatcher(
     fun close() {
         registeredFunctions.clear()
     }
+
+    private companion object {
+        const val MAX_REDIRECTS = 5
+    }
 }
diff --git a/shared/src/commonMain/kotlin/com/bricks/mp/core/BricksHttp.kt b/shared/src/commonMain/kotlin/com/bricks/mp/core/BricksHttp.kt
index 9949ffe..c4758bb 100644
--- a/shared/src/commonMain/kotlin/com/bricks/mp/core/BricksHttp.kt
+++ b/shared/src/commonMain/kotlin/com/bricks/mp/core/BricksHttp.kt
@@ -6,11 +6,32 @@ import io.ktor.client.plugins.cookies.*
 import io.ktor.client.request.*
 import io.ktor.client.statement.*
 import io.ktor.http.*
+import io.ktor.http.encodeURLParameter
 import kotlinx.serialization.json.*
 
+/**
+ * HTTP error surfaced by BricksHttp before the response body is parsed.
+ * UI layers can map this to dialogs, messages or navigation without coupling
+ * the library to a specific product/application.
+ */
+class BricksHttpException(
+    val statusCode: Int,
+    val responseBody: String,
+    val location: String? = null,
+    val requestUrl: String? = null
+) : Exception(buildMessage(statusCode, responseBody, location)) {
+    companion object {
+        private fun buildMessage(statusCode: Int, responseBody: String, location: String?): String {
+            val detail = responseBody.take(500).ifBlank { location.orEmpty() }
+            return "HTTP $statusCode${if (detail.isBlank()) "" else ": $detail"}"
+        }
+    }
+}
+
 /**
  * Bricks HTTP 客户端 - 对应 JS 版 HttpJson/HttpText
- * 支持 session cookie 管理和 Bearer token 认证
+ * 支持 session cookie 管理和 Bearer token 认证，并将 .ui/.dspy 请求自动追加
+ * WebBricks 参数：_webbricks_、_width、_height、_is_mobile、_lang。
  */
 class BricksHttp(private val context: BricksContext? = null) {
 
@@ -21,6 +42,27 @@ class BricksHttp(private val context: BricksContext? = null) {
             storage = cookieStorage
         }
         expectSuccess = false
+        followRedirects = false
+    }
+
+    /**
+     * Runtime viewport/language context appended to .ui/.dspy backend requests.
+     */
+    var requestContext: WebBricksRequestContext = WebBricksRequestContext()
+        private set
+
+    fun updateRequestContext(
+        width: Int = requestContext.width,
+        height: Int = requestContext.height,
+        isMobile: Boolean = requestContext.isMobile,
+        lang: String = requestContext.lang
+    ) {
+        requestContext = WebBricksRequestContext(
+            width = width,
+            height = height,
+            isMobile = isMobile,
+            lang = lang
+        )
     }
 
     /**
@@ -31,20 +73,8 @@ class BricksHttp(private val context: BricksContext? = null) {
         params: Map<String, String> = emptyMap(),
         authToken: String = ""
     ): JsonObject {
-        val response = client.get(url) {
-            url {
-                params.forEach { (k, v) -> parameters.append(k, v) }
-            }
-            if (authToken.isNotEmpty()) {
-                header(HttpHeaders.Authorization, "Bearer $authToken")
-            }
-        }
-        val body = response.bodyAsText()
-        return try {
-            Json.parseToJsonElement(body).jsonObject
-        } catch (e: Exception) {
-            JsonObject(mapOf("error" to JsonPrimitive("Failed to parse JSON: ${e.message}"), "raw" to JsonPrimitive(body)))
-        }
+        val text = getText(url, params, authToken)
+        return parseJsonObjectOrError(text)
     }
 
     /**
@@ -56,10 +86,9 @@ class BricksHttp(private val context: BricksContext? = null) {
         params: Map<String, String> = emptyMap(),
         authToken: String = ""
     ): JsonObject {
+        val requestParams = params.withBackendContextIfNeeded(url)
         val response = client.post(url) {
-            url {
-                params.forEach { (k, v) -> parameters.append(k, v) }
-            }
+            appendQueryParameters(requestParams)
             contentType(ContentType.Application.Json)
             setBody(body)
             if (authToken.isNotEmpty()) {
@@ -67,11 +96,8 @@ class BricksHttp(private val context: BricksContext? = null) {
             }
         }
         val text = response.bodyAsText()
-        return try {
-            Json.parseToJsonElement(text).jsonObject
-        } catch (e: Exception) {
-            JsonObject(mapOf("error" to JsonPrimitive("Failed to parse JSON: ${e.message}"), "raw" to JsonPrimitive(text)))
-        }
+        response.throwIfHttpError(text, url)
+        return parseJsonObjectOrError(text)
     }
 
     /**
@@ -82,17 +108,21 @@ class BricksHttp(private val context: BricksContext? = null) {
         form: Map<String, String>,
         authToken: String = ""
     ): String {
+        val requestParams = emptyMap<String, String>().withBackendContextIfNeeded(url)
         val formBody = form.entries.joinToString("&") { (k, v) ->
-            "${java.net.URLEncoder.encode(k, "UTF-8")}=${java.net.URLEncoder.encode(v, "UTF-8")}"
+            "${k.encodeURLParameter()}=${v.encodeURLParameter()}"
         }
         val response = client.post(url) {
+            appendQueryParameters(requestParams)
             contentType(ContentType.Application.FormUrlEncoded)
             setBody(formBody)
             if (authToken.isNotEmpty()) {
                 header(HttpHeaders.Authorization, "Bearer $authToken")
             }
         }
-        return response.bodyAsText()
+        val text = response.bodyAsText()
+        response.throwIfHttpError(text, url)
+        return text
     }
 
     /**
@@ -103,15 +133,16 @@ class BricksHttp(private val context: BricksContext? = null) {
         params: Map<String, String> = emptyMap(),
         authToken: String = ""
     ): String {
+        val requestParams = params.withBackendContextIfNeeded(url)
         val response = client.get(url) {
-            url {
-                params.forEach { (k, v) -> parameters.append(k, v) }
-            }
+            appendQueryParameters(requestParams)
             if (authToken.isNotEmpty()) {
                 header(HttpHeaders.Authorization, "Bearer $authToken")
             }
         }
-        return response.bodyAsText()
+        val text = response.bodyAsText()
+        response.throwIfHttpError(text, url)
+        return text
     }
 
     /**
@@ -130,7 +161,7 @@ class BricksHttp(private val context: BricksContext? = null) {
      * 拼接 URL - 使用 context 的 baseUrl
      */
     fun resolveUrl(path: String): String {
-        if (path.startsWith("http")) return path
+        if (path.startsWith("http://") || path.startsWith("https://")) return path
         val base = context?.baseUrl ?: ""
         val cleanBase = base.trimEnd('/')
         val cleanPath = path.trimStart('/')
@@ -140,4 +171,34 @@ class BricksHttp(private val context: BricksContext? = null) {
     fun close() {
         client.close()
     }
+
+    private fun Map<String, String>.withBackendContextIfNeeded(url: String): Map<String, String> =
+        if (url.isWebBricksBackendResource()) withWebBricksRequestContext(this, requestContext) else this
+
+    private fun HttpRequestBuilder.appendQueryParameters(params: Map<String, String>) {
+        url {
+            params.forEach { (k, v) ->
+                parameters.remove(k)
+                parameters.append(k, v)
+            }
+        }
+    }
+
+    private suspend fun HttpResponse.throwIfHttpError(body: String, requestUrl: String) {
+        val code = status.value
+        if (code in 300..399 || code == 401 || code == 403 || code >= 400) {
+            throw BricksHttpException(
+                statusCode = code,
+                responseBody = body,
+                location = headers[HttpHeaders.Location],
+                requestUrl = requestUrl
+            )
+        }
+    }
+
+    private fun parseJsonObjectOrError(text: String): JsonObject = try {
+        Json.parseToJsonElement(text).jsonObject
+    } catch (e: Exception) {
+        JsonObject(mapOf("error" to JsonPrimitive("Failed to parse JSON: ${e.message}"), "raw" to JsonPrimitive(text)))
+    }
 }
diff --git a/shared/src/commonMain/kotlin/com/bricks/mp/core/WebBricksRequestContext.kt b/shared/src/commonMain/kotlin/com/bricks/mp/core/WebBricksRequestContext.kt
new file mode 100644
index 0000000..8b9f396
--- /dev/null
+++ b/shared/src/commonMain/kotlin/com/bricks/mp/core/WebBricksRequestContext.kt
@@ -0,0 +1,56 @@
+package com.bricks.mp.core
+
+/**
+ * Backend request context required by bricks-mp when loading server-side .ui/.dspy resources.
+ *
+ * bricks-mp runs the frontend runtime in the client, so every backend .ui/.dspy
+ * request must identify itself as webbricks and carry viewport/language metadata.
+ */
+data class WebBricksRequestContext(
+    val width: Int = DEFAULT_WIDTH,
+    val height: Int = DEFAULT_HEIGHT,
+    val isMobile: Boolean = DEFAULT_IS_MOBILE,
+    val lang: String = DEFAULT_LANG
+) {
+    fun toQueryParameters(): Map<String, String> = mapOf(
+        PARAM_WEBBRICKS to "1",
+        PARAM_WIDTH to width.toString(),
+        PARAM_HEIGHT to height.toString(),
+        PARAM_IS_MOBILE to if (isMobile) "1" else "0",
+        PARAM_LANG to lang
+    )
+
+    companion object {
+        const val PARAM_WEBBRICKS = "_webbricks_"
+        const val PARAM_WIDTH = "_width"
+        const val PARAM_HEIGHT = "_height"
+        const val PARAM_IS_MOBILE = "_is_mobile"
+        const val PARAM_LANG = "_lang"
+
+        const val DEFAULT_WIDTH = 1280
+        const val DEFAULT_HEIGHT = 800
+        const val DEFAULT_IS_MOBILE = false
+        const val DEFAULT_LANG = "zh-CN"
+    }
+}
+
+/**
+ * Merge caller parameters with bricks-mp request context.
+ *
+ * Caller parameters may override viewport/language values when explicitly supplied,
+ * but _webbricks_ is always forced to 1 for .ui/.dspy backend requests.
+ */
+fun withWebBricksRequestContext(
+    params: Map<String, String>,
+    context: WebBricksRequestContext
+): Map<String, String> {
+    val merged = context.toQueryParameters().toMutableMap()
+    merged.putAll(params)
+    merged[WebBricksRequestContext.PARAM_WEBBRICKS] = "1"
+    return merged
+}
+
+fun String.isWebBricksBackendResource(): Boolean {
+    val path = substringBefore('?').substringBefore('#')
+    return path.endsWith(".ui") || path.endsWith(".dspy")
+}
diff --git a/shared/src/commonMain/kotlin/com/bricks/mp/sage/SageClient.kt b/shared/src/commonMain/kotlin/com/bricks/mp/sage/SageClient.kt
deleted file mode 100644
index 454a81a..0000000
--- a/shared/src/commonMain/kotlin/com/bricks/mp/sage/SageClient.kt
+++ /dev/null
@@ -1,229 +0,0 @@
-package com.bricks.mp.sage
-
-import com.bricks.mp.core.BricksParser
-import com.bricks.mp.core.BricksWidget
-import io.ktor.client.*
-import io.ktor.client.engine.cio.*
-import io.ktor.client.plugins.cookies.*
-import io.ktor.client.request.*
-import io.ktor.client.statement.*
-import io.ktor.http.*
-import kotlinx.coroutines.sync.Mutex
-import kotlinx.coroutines.sync.withLock
-import kotlinx.serialization.json.*
-
-/**
- * Sage 客户端 - 处理登录、Session 管理和 UI 加载
- * 
- * Sage 使用 Cookie Session 认证：
- * 1. GET 首页获取初始 session cookie
- * 2. POST /rbac/user/up_login.dspy 登录
- * 3. 后续请求自动携带 cookie
- * 4. GET /xxx.ui 获取 JSON 格式的 UI 描述
- */
-class SageClient {
-
-    companion object {
-        const val DEFAULT_BASE_URL = "https://ai.atvoe.com"
-    }
-
-    private val cookieStorage = AcceptAllCookiesStorage()
-
-    private val client = HttpClient(CIO) {
-        install(HttpCookies) {
-            storage = cookieStorage
-        }
-        expectSuccess = false
-        followRedirects = true
-    }
-
-    var baseUrl: String = DEFAULT_BASE_URL
-
-    // 登录状态
-    private val _isLoggedIn = kotlinx.coroutines.flow.MutableStateFlow(false)
-    val isLoggedIn: kotlinx.coroutines.flow.StateFlow<Boolean> = _isLoggedIn
-
-    private val _loginError = kotlinx.coroutines.flow.MutableStateFlow<String?>(null)
-    val loginError: kotlinx.coroutines.flow.StateFlow<String?> = _loginError
-
-    private val mutex = Mutex()
-
-    /**
-     * 登录 Sage 服务器
-     * POST /rbac/user/up_login.dspy
-     */
-    suspend fun login(username: String, password: String): Boolean = mutex.withLock {
-        _loginError.value = null
-        try {
-            // Step 1: GET the index page to obtain initial session cookies
-            // Sage requires a valid session cookie before accepting login POST
-            val indexResponse = client.get("$baseUrl/")
-            println("[Sage] GET / status: ${indexResponse.status}")
-
-            // Step 2: POST login
-            val url = "$baseUrl/rbac/user/up_login.dspy"
-            val encodedUser = java.net.URLEncoder.encode(username, "UTF-8")
-            val encodedPass = java.net.URLEncoder.encode(password, "UTF-8")
-            val formBody = "username=$encodedUser&password=$encodedPass"
-
-            val response = client.post(url) {
-                header(HttpHeaders.UserAgent, "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36")
-                header(HttpHeaders.Referrer, "$baseUrl/")
-                contentType(ContentType.Application.FormUrlEncoded)
-                setBody(formBody)
-            }
-
-            val body = response.bodyAsText()
-            println("[Sage] Login response status: ${response.status}")
-            println("[Sage] Login response body: ${body.take(300)}")
-
-            // Check if response is JSON
-            if (!body.trimStart().startsWith("{")) {
-                // Non-JSON response - likely an error page or auth failure
-                if (response.status.value == 401 || response.status.value == 403) {
-                    _loginError.value = "登录失败: 服务器拒绝请求 (${response.status.value})"
-                } else {
-                    _loginError.value = "登录失败: 服务器返回非JSON响应 (${response.status.value})"
-                }
-                println("[Sage] Non-JSON login response: ${body.take(200)}")
-                return@withLock false
-            }
-
-            // Sage 返回 UiMessage 格式: {"widgettype": "Message", "options": {...}}
-            val json = try {
-                Json.parseToJsonElement(body).jsonObject
-            } catch (e: Exception) {
-                _loginError.value = "登录响应解析错误: ${e.message}"
-                return@withLock false
-            }
-
-            val widgetType = json["widgettype"]?.jsonPrimitive?.content
-
-            if (widgetType == "Message" || widgetType == "UiMessage") {
-                val cookies = cookieStorage.get(URLBuilder(baseUrl).build())
-                println("[Sage] Login successful, cookies: ${cookies.size}")
-                _isLoggedIn.value = true
-                true
-            } else {
-                // 错误消息
-                val options = json["options"]?.jsonObject ?: JsonObject(emptyMap())
-                val message = options["message"]?.jsonPrimitive?.content
-                    ?: options["text"]?.jsonPrimitive?.content
-                    ?: body.take(100)
-                _loginError.value = message
-                println("[Sage] Login failed: $message")
-                false
-            }
-        } catch (e: Exception) {
-            _loginError.value = "登录失败: ${e.message}"
-            println("[Sage] Login error: ${e.message}")
-            false
-        }
-    }
-
-    /**
-     * 获取 .ui 文件（JSON 格式的 UI 描述）
-     */
-    suspend fun fetchUi(path: String): Result<BricksWidget> = mutex.withLock {
-        try {
-            val url = if (path.startsWith("http")) path else "$baseUrl/${path.trimStart('/')}"
-            println("[Sage] Fetching UI: $url")
-
-            val response = client.get(url) {
-                header(HttpHeaders.UserAgent, "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36")
-            }
-            val body = response.bodyAsText()
-
-            if (!response.status.isSuccess()) {
-                return@withLock Result.failure(Exception("HTTP ${response.status.value}: ${body.take(200)}"))
-            }
-
-            val widget = BricksParser.parse(body)
-            Result.success(widget)
-        } catch (e: Exception) {
-            println("[Sage] Fetch UI error: ${e.message}")
-            Result.failure(e)
-        }
-    }
-
-    /**
-     * 获取 .dspy API 返回的 JSON
-     */
-    suspend fun fetchApi(
-        path: String,
-        params: Map<String, String> = emptyMap(),
-        method: String = "GET",
-        formBody: Map<String, String> = emptyMap(),
-        jsonBody: JsonObject? = null
-    ): Result<JsonObject> = mutex.withLock {
-        try {
-            val url = if (path.startsWith("http")) path else "$baseUrl/${path.trimStart('/')}"
-
-            val response = when (method.uppercase()) {
-                "POST" -> client.post(url) {
-                    url {
-                        params.forEach { (k, v) -> parameters.append(k, v) }
-                    }
-                    header(HttpHeaders.UserAgent, "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36")
-                    when {
-                        jsonBody != null -> {
-                            contentType(ContentType.Application.Json)
-                            setBody(jsonBody)
-                        }
-                        formBody.isNotEmpty() -> {
-                            val bodyStr = formBody.entries.joinToString("&") { (k, v) ->
-                                "${java.net.URLEncoder.encode(k, "UTF-8")}=${java.net.URLEncoder.encode(v, "UTF-8")}"
-                            }
-                            contentType(ContentType.Application.FormUrlEncoded)
-                            setBody(bodyStr)
-                        }
-                    }
-                }
-                else -> client.get(url) {
-                    url {
-                        params.forEach { (k, v) -> parameters.append(k, v) }
-                    }
-                    header(HttpHeaders.UserAgent, "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36")
-                }
-            }
-
-            val body = response.bodyAsText()
-            val json = Json.parseToJsonElement(body).jsonObject
-            Result.success(json)
-        } catch (e: Exception) {
-            Result.failure(e)
-        }
-    }
-
-    /**
-     * 获取文本内容
-     */
-    suspend fun fetchText(path: String): Result<String> = mutex.withLock {
-        try {
-            val url = if (path.startsWith("http")) path else "$baseUrl/${path.trimStart('/')}"
-            val response = client.get(url)
-            Result.success(response.bodyAsText())
-        } catch (e: Exception) {
-            Result.failure(e)
-        }
-    }
-
-    /**
-     * 退出登录
-     */
-    suspend fun logout() = mutex.withLock {
-        try {
-            _isLoggedIn.value = false
-            println("[Sage] Logged out")
-        } catch (e: Exception) {
-            println("[Sage] Logout error: ${e.message}")
-        }
-    }
-
-    /**
-     * 关闭客户端
-     */
-    fun close() {
-        client.close()
-    }
-}
diff --git a/shared/src/jvmMain/kotlin/com/bricks/Main.kt b/shared/src/jvmMain/kotlin/com/bricks/Main.kt
index 3a89723..b3cb580 100644
--- a/shared/src/jvmMain/kotlin/com/bricks/Main.kt
+++ b/shared/src/jvmMain/kotlin/com/bricks/Main.kt
@@ -1,366 +1,178 @@
 package com.bricks
 
-import androidx.compose.foundation.background
-import androidx.compose.foundation.layout.*
-import androidx.compose.foundation.rememberScrollState
-import androidx.compose.foundation.text.KeyboardOptions
-import androidx.compose.foundation.verticalScroll
-import androidx.compose.material3.*
-import androidx.compose.runtime.*
-import androidx.compose.ui.Alignment
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TopAppBar
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.text.input.PasswordVisualTransformation
-import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Window
-import androidx.compose.ui.window.WindowPlacement
 import androidx.compose.ui.window.WindowState
 import androidx.compose.ui.window.application
+import com.bricks.mp.actions.ActionDispatcher
 import com.bricks.mp.core.BricksContext
 import com.bricks.mp.core.BricksHttp
 import com.bricks.mp.core.BricksWidget
 import com.bricks.mp.core.RenderWidget
-import com.bricks.mp.actions.ActionDispatcher
-import com.bricks.mp.sage.SageClient
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
+import java.awt.event.ComponentAdapter
+import java.awt.event.ComponentEvent
+import java.util.Locale
 
 /**
- * Sage macOS 桌面客户端入口
- * 登录 Sage 服务器 -> 加载 UI -> 渲染
+ * Generic bricks-mp desktop host entry.
+ *
+ * Product-specific bootstrapping (for example Sage login and center.ui loading)
+ * belongs in the application project. See README.md for a Sage application sample.
  */
 fun main() = application {
-    val sageClient = remember { SageClient() }
     val context = remember { BricksContext() }
     val http = remember { BricksHttp(context) }
     val scope = rememberCoroutineScope()
+    val windowState = remember { WindowState(width = 1280.dp, height = 800.dp) }
 
-    var isLoggedIn by remember { mutableStateOf(false) }
-    var currentWidget by remember { mutableStateOf<BricksWidget?>(null) }
-    var isLoading by remember { mutableStateOf(false) }
-    var errorMessage by remember { mutableStateOf<String?>(null) }
-
-    // 初始化上下文
     LaunchedEffect(Unit) {
-        context.baseUrl = SageClient.DEFAULT_BASE_URL
+        context.baseUrl = System.getProperty("bricks.baseUrl", "http://localhost:8080")
+        runCatching { http.fetchUi(System.getProperty("bricks.entry", "/")) }
+            .onSuccess { context.setCurrentWidget(it) }
+            .onFailure { println("[Bricks] Failed to load entry UI: ${it.message}") }
     }
 
     Window(
         onCloseRequest = {
-            sageClient.close()
             http.close()
             exitApplication()
         },
-        title = if (isLoggedIn) "Sage" else "Sage - Login",
-        state = remember {
-            WindowState(
-                placement = if (isLoggedIn) WindowPlacement.Maximized else WindowPlacement.Floating,
-                width = if (isLoggedIn) 1280.dp else 400.dp,
-                height = if (isLoggedIn) 800.dp else 500.dp
-            )
-        }
+        title = "bricks-mp",
+        state = windowState
     ) {
-        if (!isLoggedIn) {
-            // 登录界面
-            LoginScreen(
-                sageClient = sageClient,
-                onLoginSuccess = {
-                    isLoggedIn = true
-                    // 登录后加载主 UI
-                    scope.launch(Dispatchers.IO) {
-                        isLoading = true
-                        errorMessage = null
-                        // Sage 登录后加载入口 UI
-                        val result = sageClient.fetchUi("center.ui")
-                        result.fold(
-                            onSuccess = { widget ->
-                                currentWidget = widget
-                                isLoading = false
-                            },
-                            onFailure = { e ->
-                                errorMessage = "加载主界面失败: ${e.message}"
-                                isLoading = false
-                            }
-                        )
+        MaterialTheme {
+            val density = LocalDensity.current
+            val lang = remember { Locale.getDefault().toLanguageTag() }
+            val fallbackWidthPx = with(density) { windowState.size.width.roundToPx() }
+            val fallbackHeightPx = with(density) { windowState.size.height.roundToPx() }
+            var windowSizePx by remember { mutableStateOf(IntSize(fallbackWidthPx, fallbackHeightPx)) }
+            var dialogWidget by remember { mutableStateOf<BricksWidget?>(null) }
+            var message by remember { mutableStateOf<Triple<String, String, Boolean>?>(null) }
+
+            DisposableEffect(window) {
+                fun updateWindowSize() {
+                    val size = window.size
+                    if (size.width > 0 && size.height > 0) {
+                        windowSizePx = IntSize(size.width, size.height)
                     }
-                },
-                onLoginError = { error ->
-                    errorMessage = error
                 }
-            )
-        } else {
-            // 主应用界面
-            if (isLoading) {
-                LoadingScreen()
-            } else if (currentWidget != null) {
-                MainAppScreen(
-                    rootWidget = currentWidget!!,
-                    context = context,
-                    http = http,
-                    sageClient = sageClient,
-                    scope = scope,
-                    onLogout = {
-                        scope.launch {
-                            sageClient.logout()
-                            isLoggedIn = false
-                            currentWidget = null
-                        }
-                    },
-                    onNavigate = { path ->
-                        scope.launch(Dispatchers.IO) {
-                            isLoading = true
-                            errorMessage = null
-                            val result = sageClient.fetchUi(path)
-                            result.fold(
-                                onSuccess = { widget ->
-                                    currentWidget = widget
-                                    isLoading = false
-                                },
-                                onFailure = { e ->
-                                    errorMessage = "加载失败: ${e.message}"
-                                    isLoading = false
-                                }
-                            )
-                        }
-                    }
-                )
-            } else {
-                ErrorScreen(
-                    message = errorMessage ?: "无法加载主界面",
-                    onRetry = {
-                        scope.launch(Dispatchers.IO) {
-                            isLoading = true
-                            errorMessage = null
-                            val result = sageClient.fetchUi("center.ui")
-                            result.fold(
-                                onSuccess = { widget ->
-                                    currentWidget = widget
-                                    isLoading = false
-                                },
-                                onFailure = { e ->
-                                    errorMessage = "加载失败: ${e.message}"
-                                    isLoading = false
-                                }
-                            )
-                        }
-                    }
+
+                val listener = object : ComponentAdapter() {
+                    override fun componentResized(e: ComponentEvent) = updateWindowSize()
+                    override fun componentShown(e: ComponentEvent) = updateWindowSize()
+                }
+
+                updateWindowSize()
+                window.addComponentListener(listener)
+                onDispose { window.removeComponentListener(listener) }
+            }
+
+            LaunchedEffect(windowSizePx, lang) {
+                http.updateRequestContext(
+                    width = windowSizePx.width.takeIf { it > 0 } ?: fallbackWidthPx,
+                    height = windowSizePx.height.takeIf { it > 0 } ?: fallbackHeightPx,
+                    isMobile = false,
+                    lang = lang
                 )
             }
-        }
 
-        // 错误提示
-        errorMessage?.let { msg ->
-            LaunchedEffect(msg) {
-                // 可以通过 dialog 显示错误
-                println("[Sage] Error: $msg")
+            val actionDispatcher = remember(context, http, scope) {
+                ActionDispatcher(context = context, http = http, scope = scope).apply {
+                    onWidgetLoaded = { widget -> context.setCurrentWidget(widget) }
+                    onDialog = { widget, show -> dialogWidget = if (show) widget else null }
+                    onMessage = { title, body, isError -> message = Triple(title, body, isError) }
+                }
             }
-        }
-    }
-}
 
-/**
- * 登录界面
- */
-@Composable
-fun LoginScreen(
-    sageClient: SageClient,
-    onLoginSuccess: () -> Unit,
-    onLoginError: (String) -> Unit
-) {
-    var username by remember { mutableStateOf("") }
-    var password by remember { mutableStateOf("") }
-    var isLoading by remember { mutableStateOf(false) }
-    var loginError by remember { mutableStateOf<String?>(null) }
-    var baseUrl by remember { mutableStateOf(SageClient.DEFAULT_BASE_URL) }
-
-    val scope = rememberCoroutineScope()
-
-    Surface(modifier = Modifier.fillMaxSize()) {
-        Column(
-            modifier = Modifier
-                .fillMaxSize()
-                .padding(32.dp)
-                .verticalScroll(rememberScrollState()),
-            horizontalAlignment = Alignment.CenterHorizontally,
-            verticalArrangement = Arrangement.Center
-        ) {
-            // Logo / Title
-            Text(
-                text = "Sage",
-                fontSize = 36.sp,
-                fontWeight = FontWeight.Bold,
-                modifier = Modifier.padding(bottom = 8.dp)
-            )
-            Text(
-                text = "AI 平台",
-                fontSize = 16.sp,
-                color = MaterialTheme.colorScheme.onSurfaceVariant,
-                modifier = Modifier.padding(bottom = 32.dp)
-            )
-
-            // Server URL
-            OutlinedTextField(
-                value = baseUrl,
-                onValueChange = { baseUrl = it },
-                label = { Text("服务器地址") },
-                modifier = Modifier.fillMaxWidth().padding(bottom = 8.dp),
-                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Uri)
-            )
-
-            // Username
-            OutlinedTextField(
-                value = username,
-                onValueChange = { username = it },
-                label = { Text("用户名") },
-                modifier = Modifier.fillMaxWidth().padding(bottom = 8.dp),
-                singleLine = true
-            )
-
-            // Password
-            OutlinedTextField(
-                value = password,
-                onValueChange = { password = it },
-                label = { Text("密码") },
-                modifier = Modifier.fillMaxWidth().padding(bottom = 16.dp),
-                visualTransformation = PasswordVisualTransformation(),
-                singleLine = true
-            )
-
-            // Login button
-            Button(
-                onClick = {
+            val currentWidget by context.currentWidget.collectAsState()
+            BricksHostScreen(
+                widget = currentWidget,
+                actionDispatcher = actionDispatcher,
+                onReload = {
                     scope.launch {
-                        isLoading = true
-                        loginError = null
-                        sageClient.baseUrl = baseUrl
-
-                        val success = sageClient.login(username, password)
-                        if (success) {
-                            onLoginSuccess()
-                        } else {
-                            loginError = sageClient.loginError.value ?: "登录失败"
-                            onLoginError(loginError!!)
-                        }
-                        isLoading = false
+                        runCatching { http.fetchUi(System.getProperty("bricks.entry", "/")) }
+                            .onSuccess { context.setCurrentWidget(it) }
+                            .onFailure { message = Triple("Error", it.message ?: "Load failed", true) }
                     }
-                },
-                enabled = !isLoading && username.isNotBlank() && password.isNotBlank(),
-                modifier = Modifier.fillMaxWidth().height(48.dp)
-            ) {
-                if (isLoading) {
-                    CircularProgressIndicator(modifier = Modifier.size(24.dp), strokeWidth = 2.dp)
-                } else {
-                    Text("登录", fontSize = 16.sp)
                 }
+            )
+
+            dialogWidget?.let { widget ->
+                AlertDialog(
+                    onDismissRequest = { dialogWidget = null },
+                    title = { Text("Login") },
+                    text = { RenderWidget(widget, actionDispatcher) },
+                    confirmButton = {
+                        TextButton(onClick = { dialogWidget = null }) { Text("Close") }
+                    }
+                )
             }
 
-            // Error message
-            loginError?.let { error ->
-                Text(
-                    text = error,
-                    color = MaterialTheme.colorScheme.error,
-                    modifier = Modifier.padding(top = 16.dp),
-                    fontSize = 14.sp
+            message?.let { (title, body, _) ->
+                AlertDialog(
+                    onDismissRequest = { message = null },
+                    title = { Text(title) },
+                    text = { Text(body) },
+                    confirmButton = {
+                        TextButton(onClick = { message = null }) { Text("OK") }
+                    }
                 )
             }
         }
     }
 }
 
-/**
- * 主应用界面
- */
 @OptIn(androidx.compose.material3.ExperimentalMaterial3Api::class)
 @Composable
-fun MainAppScreen(
-    rootWidget: BricksWidget,
-    context: BricksContext,
-    http: BricksHttp,
-    sageClient: SageClient,
-    scope: kotlinx.coroutines.CoroutineScope,
-    onLogout: () -> Unit,
-    onNavigate: (String) -> Unit
+private fun BricksHostScreen(
+    widget: BricksWidget?,
+    actionDispatcher: ActionDispatcher,
+    onReload: () -> Unit
 ) {
-    val actionDispatcher = remember {
-        ActionDispatcher(
-            context = context,
-            http = http,
-            sageClient = sageClient,
-            scope = scope
-        ).apply {
-            onWidgetLoaded = { widget ->
-                context.setCurrentWidget(widget)
-            }
-            onMessage = { title, message, isError ->
-                println("[Sage] Message: $title - $message (error: $isError)")
-            }
-        }
-    }
-
-    // 监听 widget 变化
-    val currentWidget by context.currentWidget.collectAsState()
-
     Scaffold(
         topBar = {
             TopAppBar(
-                title = { Text("Sage") },
+                title = { Text("bricks-mp") },
                 actions = {
-                    TextButton(onClick = onLogout) {
-                        Text("退出")
+                    Button(onClick = onReload, modifier = Modifier.padding(end = 8.dp)) {
+                        Text("Reload")
                     }
                 }
             )
         }
     ) { padding ->
         Box(modifier = Modifier.padding(padding).fillMaxSize()) {
-            val widgetToRender = currentWidget ?: rootWidget
-            RenderWidget(
-                widget = widgetToRender,
-                actionDispatcher = actionDispatcher,
-                modifier = Modifier.fillMaxSize()
-            )
-        }
-    }
-}
-
-/**
- * 加载界面
- */
-@Composable
-fun LoadingScreen() {
-    Surface(modifier = Modifier.fillMaxSize()) {
-        Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-            Column(horizontalAlignment = Alignment.CenterHorizontally) {
-                CircularProgressIndicator()
-                Spacer(modifier = Modifier.height(16.dp))
-                Text("加载中...")
-            }
-        }
-    }
-}
-
-/**
- * 错误界面
- */
-@Composable
-fun ErrorScreen(
-    message: String,
-    onRetry: () -> Unit
-) {
-    Surface(modifier = Modifier.fillMaxSize()) {
-        Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-            Column(horizontalAlignment = Alignment.CenterHorizontally) {
-                Text("❌", fontSize = 48.sp)
-                Spacer(modifier = Modifier.height(16.dp))
-                Text(message)
-                Spacer(modifier = Modifier.height(16.dp))
-                Button(onClick = onRetry) {
-                    Text("重试")
-                }
+            if (widget == null) {
+                Text("No UI loaded", modifier = Modifier.padding(24.dp))
+            } else {
+                RenderWidget(
+                    widget = widget,
+                    actionDispatcher = actionDispatcher,
+                    modifier = Modifier.fillMaxSize()
+                )
             }
         }
     }