diff --git a/neode-ui/src/services/contextBroker.ts b/neode-ui/src/services/contextBroker.ts
index 30b7dec2..1ae55e8c 100644
--- a/neode-ui/src/services/contextBroker.ts
+++ b/neode-ui/src/services/contextBroker.ts
@@ -5,6 +5,7 @@ import type {
   AIContextCategory,
   ArchyContextResponse,
   ArchyActionResponse,
+  ArchyChatResponse,
 } from '@/types/aiui-protocol'
 import { useAIPermissionsStore } from '@/stores/aiPermissions'
 import { useAppStore } from '@/stores/app'
@@ -81,6 +82,37 @@ export class ContextBroker {
       case 'theme:request':
         this.sendTheme()
         break
+      case 'chat:request':
+        this.handleChatRequest(msg.id, msg.text)
+        break
+    }
+  }
+
+  // Note: no permission category is threaded through here on purpose.
+  // Authority for a chat turn is resolved node-side from the RPC session's
+  // CallerScope (assistant.chat, core/archipelago/src/assistant/mod.rs) —
+  // duplicating a browser-side gate here would recreate the second,
+  // divergent security model D-02 exists to prevent. Do not "helpfully"
+  // add a permission check back into this handler.
+  private async handleChatRequest(id: string, text: string) {
+    try {
+      const result = await rpcClient.call<{ text: string }>({
+        method: 'assistant.chat',
+        params: { text },
+      })
+      this.postToIframe({
+        type: 'chat:response',
+        id,
+        success: true,
+        text: result.text,
+      } satisfies ArchyChatResponse)
+    } catch (err) {
+      this.postToIframe({
+        type: 'chat:response',
+        id,
+        success: false,
+        error: err instanceof Error ? err.message : 'Chat request failed',
+      } satisfies ArchyChatResponse)
     }
   }
 
diff --git a/neode-ui/src/types/aiui-protocol.ts b/neode-ui/src/types/aiui-protocol.ts
index a1aa2361..d799ba0a 100644
--- a/neode-ui/src/types/aiui-protocol.ts
+++ b/neode-ui/src/types/aiui-protocol.ts
@@ -45,11 +45,24 @@ export interface AIUIThemeRequest {
   type: 'theme:request'
 }
 
+/**
+ * A chat turn from AIUI's embedded-mode client. Carries only the raw user
+ * text — tool selection is node-side (D-01/D-03) and must never be
+ * expressible as an AIUI-originated action, so this is deliberately NOT an
+ * `AIActionType` member.
+ */
+export interface AIUIChatRequest {
+  type: 'chat:request'
+  id: string
+  text: string
+}
+
 export type AIUIRequest =
   | AIUIContextRequest
   | AIUIActionRequest
   | AIUIReadyMessage
   | AIUIThemeRequest
+  | AIUIChatRequest
 
 // ─── Archy → AIUI (Responses) ──────────────────────────────────────────────
 
@@ -81,11 +94,22 @@ export interface ArchyPermissionsUpdate {
   categories: AIContextCategory[]
 }
 
+/** The node's answer to a `chat:request`. On RPC failure, `error` carries
+ * only the error message — never the raw exception object. */
+export interface ArchyChatResponse {
+  type: 'chat:response'
+  id: string
+  success: boolean
+  text?: string
+  error?: string
+}
+
 export type ArchyResponse =
   | ArchyContextResponse
   | ArchyActionResponse
   | ArchyThemeResponse
   | ArchyPermissionsUpdate
+  | ArchyChatResponse
 
 // ─── All messages ───────────────────────────────────────────────────────────