diff --git a/packages/app/src/composables/useAI.ts b/packages/app/src/composables/useAI.ts
index 8826dfa2..f3f698a0 100644
--- a/packages/app/src/composables/useAI.ts
+++ b/packages/app/src/composables/useAI.ts
@@ -6,6 +6,7 @@ import type { ImageAttachment } from '@aiui/core/types/message'
 import { usePersonaStore } from '@/stores/personas'
 import { useMemoryStore } from '@/stores/memory'
 import { useArchy } from '@/composables/useArchy'
+import { archyBridge } from '@/services/archyBridge'
 import { useCodeContext } from '@/composables/useCodeContext'
 import { apiFetch } from '@/utils/api-fetch'
 import { useSettingsStore } from '@/stores/settings'
@@ -374,6 +375,33 @@ async function streamOpenRouter(
   }, onError, signal)
 }
 
+/**
+ * Embedded-mode chat delegation (D-01/D-17): when AIUI is running inside
+ * Archy, the model call, the tool-calling loop, and the model key all live
+ * node-side. This sends only the latest user turn over the existing
+ * origin-checked postMessage bridge (`archyBridge.sendChat`) and emits the
+ * node's final answer as a single token — there is no streaming across the
+ * bridge in this tracer, only a one-shot `chat:request`/`chat:response`
+ * round trip.
+ */
+async function streamViaArchy(
+  messages: ChatMessage[],
+  onToken: (text: string) => void,
+  onError: (err: string) => void,
+  signal?: AbortSignal,
+): Promise<void> {
+  const lastUser = [...messages].reverse().find((m) => m.role === 'user')
+  const text = lastUser?.content ?? ''
+  try {
+    const result = await archyBridge.sendChat(text)
+    if (signal?.aborted) return
+    onToken(result.text)
+  } catch (err) {
+    if (signal?.aborted) return
+    onError(err instanceof Error ? err.message : 'Archy chat request failed')
+  }
+}
+
 async function readSSE(
   res: Response,
   onData: (data: string) => void,
@@ -560,7 +588,11 @@ export async function streamWithModel(
   activeModel.value = model
 
   try {
-    if (provider === 'claude') {
+    if (useArchy().isEmbedded.value) {
+      // D-17: embedded mode delegates the loop, the tools and the key to
+      // Archy — provider/model selection here doesn't apply node-side.
+      await streamViaArchy(history, onToken, onError, signal)
+    } else if (provider === 'claude') {
       await streamClaude(history, onToken, onError, 'You are a helpful assistant.', false, signal)
     } else if (provider === 'openrouter') {
       await streamOpenRouter(history, onToken, onError, 'You are a helpful assistant.', signal)
@@ -643,7 +675,11 @@ export function useAI() {
     const genParams = getConversationParams(chatStore)
 
     try {
-      if (provider === 'claude') {
+      if (useArchy().isEmbedded.value) {
+        // D-17: embedded mode delegates the loop, the tools and the key to
+        // Archy — provider/model selection here doesn't apply node-side.
+        await streamViaArchy(history, onToken, onError, signal)
+      } else if (provider === 'claude') {
         await streamClaude(history, onToken, onError, systemPrompt, proxyWebSearch, signal, genParams)
       } else if (provider === 'openrouter') {
         await streamOpenRouter(history, onToken, onError, systemPrompt, signal)
@@ -755,7 +791,11 @@ export function useAI() {
     const genParams = getConversationParams(chatStore)
 
     try {
-      if (provider === 'claude') {
+      if (useArchy().isEmbedded.value) {
+        // D-17: embedded mode delegates the loop, the tools and the key to
+        // Archy — provider/model selection here doesn't apply node-side.
+        await streamViaArchy(history, onToken, onError, signal)
+      } else if (provider === 'claude') {
         await streamClaude(history, onToken, onError, systemPrompt, chatStore.webSearchEnabled, signal, genParams)
       } else if (provider === 'openrouter') {
         await streamOpenRouter(history, onToken, onError, systemPrompt, signal)
diff --git a/packages/app/src/services/archyBridge.ts b/packages/app/src/services/archyBridge.ts
index 8cdce41f..b239d81e 100644
--- a/packages/app/src/services/archyBridge.ts
+++ b/packages/app/src/services/archyBridge.ts
@@ -74,6 +74,19 @@ function handleMessage(event: MessageEvent) {
       break
     }
 
+    case 'chat:response': {
+      const pending = pendingRequests.get(msg.id)
+      if (pending) {
+        pendingRequests.delete(msg.id)
+        if (msg.success) {
+          pending.resolve({ text: msg.text ?? '' })
+        } else {
+          pending.reject(new Error(msg.error || 'Chat request failed'))
+        }
+      }
+      break
+    }
+
     case 'permissions:update': {
       currentPermissions = msg.categories || []
       for (const cb of permissionsCallbacks) cb(currentPermissions)
@@ -189,6 +202,32 @@ export const archyBridge = {
     })
   },
 
+  /**
+   * Send a chat turn to Archy's node-side assistant loop (D-01: the model
+   * key and the tool-calling loop live on the node, never in this bundle).
+   * Returns the assistant's final text answer for this turn.
+   */
+  sendChat(text: string): Promise<{ text: string }> {
+    const id = generateId()
+    return new Promise((resolve, reject) => {
+      pendingRequests.set(id, { resolve: resolve as (v: unknown) => void, reject })
+      postToParent({
+        type: 'chat:request',
+        id,
+        text,
+      })
+
+      // Matches the node's ASSISTANT_HTTP_TIMEOUT (180s) — the assistant
+      // loop's tool-calling round trip can legitimately take that long.
+      setTimeout(() => {
+        if (pendingRequests.has(id)) {
+          pendingRequests.delete(id)
+          reject(new Error('Chat request timed out'))
+        }
+      }, 180000)
+    })
+  },
+
   /** Request Archy's theme info */
   requestTheme() {
     postToParent({ type: 'theme:request' })