diff --git a/app/backend/main.py b/app/backend/main.py
index 0d31060d..ca110bbb 100644
--- a/app/backend/main.py
+++ b/app/backend/main.py
@@ -4,6 +4,7 @@ import os
 from contextlib import asynccontextmanager
 from pathlib import Path
 
+from ag_ui.core import EventType, StateSnapshotEvent
 from dotenv import find_dotenv, load_dotenv
 from pydantic_ai import Agent
 from pydantic_ai.ui import SSE_CONTENT_TYPE
@@ -102,11 +103,33 @@ async def stream_chat(request: Request) -> Response:
 
     adapter = AGUIAdapter(agent=agent, run_input=run_input, accept=accept)
 
+    incoming_state = run_input.state if isinstance(run_input.state, dict) else {}
+
     async def event_stream():
         async with run_agui_stream(
-            adapter, toolset=toolset, deps=SkillDeps()
+            adapter, toolset=toolset, deps=SkillDeps(state=incoming_state)
         ) as stream:
-            async for chunk in adapter.encode_stream(stream):
+            # Emit a STATE_SNAPSHOT after RUN_STARTED so the client holds every
+            # namespace object before any STATE_DELTA patches into it. Without it,
+            # the first `add /rag/<field>/...` fails against a missing parent.
+            if incoming_state:
+                toolset.restore_state_snapshot(incoming_state)
+            snapshot = StateSnapshotEvent(
+                type=EventType.STATE_SNAPSHOT,
+                snapshot=toolset.build_state_snapshot(),
+            )
+
+            async def with_state_snapshot():
+                emitted = False
+                async for event in stream:
+                    yield event
+                    if not emitted and getattr(event, "type", None) == (
+                        EventType.RUN_STARTED
+                    ):
+                        yield snapshot
+                        emitted = True
+
+            async for chunk in adapter.encode_stream(with_state_snapshot()):
                 yield chunk
 
     return StreamingResponse(
@@ -216,7 +239,7 @@ async def visualize_chunk(request: Request) -> JSONResponse:
 
 
 @asynccontextmanager
-async def lifespan(app: Starlette):
+async def lifespan(_app: Starlette):
     """Shut down the cached HaikuRAG client cleanly on app exit.
 
     Awaits any in-flight background vacuum tasks and closes the LanceDB
diff --git a/app/frontend/components/Chat.tsx b/app/frontend/components/Chat.tsx
index a2f2f6b5..b1d14fed 100644
--- a/app/frontend/components/Chat.tsx
+++ b/app/frontend/components/Chat.tsx
@@ -438,13 +438,12 @@ function ChatContentInner({
 	useEffect(() => {
 		if (agent.messages.length > 0) return;
 		const session = getSession(sessionId);
-		if (!session) return;
-		if (session.ragState) {
-			agent.setState({
-				[AGUI_STATE_KEY]: normalizeRAGState(session.ragState),
-			});
-		}
-		if (session.messages.length > 0) {
+		// Seed the namespaced AG-UI state so the backend's first STATE_DELTA
+		// (e.g. add /rag/searches/...) has a namespace object to patch into.
+		agent.setState({
+			[AGUI_STATE_KEY]: normalizeRAGState(session?.ragState),
+		});
+		if (session && session.messages.length > 0) {
 			// biome-ignore lint/suspicious/noExplicitAny: AG-UI Message type is a broad union
 			agent.setMessages(session.messages as any[]);
 		}