diff --git a/backend/apps/apps_sdk/apps_sdk.py b/backend/apps/apps_sdk/apps_sdk.py
index 39de0e4d..635b4523 100644
--- a/backend/apps/apps_sdk/apps_sdk.py
+++ b/backend/apps/apps_sdk/apps_sdk.py
@@ -103,18 +103,25 @@ async def spawn_agent(body: SpawnAgentRequest) -> SpawnAgentReply:
 
     if not body.prompt.strip():
         raise HTTPException(status_code=422, detail="prompt is empty")
+    dashboard_id = body.dashboard_id
+    if dashboard_id is None:
+        # An app webview has no idea which dashboard it lives on; without one the canvas lifecycle
+        # never creates a card, so the spawn is real but invisible. Most-recent dashboard wins.
+        from backend.apps.dashboards.dashboards import load_all
+        boards = sorted(load_all(), key=lambda d: d.updated_at, reverse=True)
+        dashboard_id = boards[0].id if boards else None
     config = AgentConfig(
         name=body.name,
         prompt=body.prompt,
         model=body.model or "sonnet",
-        dashboard_id=body.dashboard_id,
+        dashboard_id=dashboard_id,
     )
     session = await agent_manager.launch_agent(config)
     asyncio.create_task(agent_manager.send_message(session.id, body.prompt))
     if body.x is not None and body.y is not None:
         await ws_manager.broadcast_global("apps_sdk:place_agent_card", {
             "session_id": session.id,
-            "dashboard_id": body.dashboard_id,
+            "dashboard_id": dashboard_id,
             "x": body.x,
             "y": body.y,
         })
diff --git a/backend/tests/test_apps_sdk.py b/backend/tests/test_apps_sdk.py
index a992164d..7f5012e1 100644
--- a/backend/tests/test_apps_sdk.py
+++ b/backend/tests/test_apps_sdk.py
@@ -89,10 +89,12 @@ def test_llm_rejects_an_empty_prompt():
 
 
 def test_spawn_agent_launches_and_broadcasts_position(monkeypatch):
+    import backend.apps.dashboards.dashboards as dash_mod
     from backend.apps.agents import agent_manager as am_mod
     from backend.apps.agents.core import ws_manager as ws_mod
     from backend.apps.agents.core.models import AgentSession
 
+    monkeypatch.setattr(dash_mod, "load_all", lambda: [], raising=True)
     launched = []
     messaged = []
     broadcasts = []
@@ -122,10 +124,12 @@ def test_spawn_agent_launches_and_broadcasts_position(monkeypatch):
 
 
 def test_spawn_agent_without_position_skips_the_broadcast(monkeypatch):
+    import backend.apps.dashboards.dashboards as dash_mod
     from backend.apps.agents import agent_manager as am_mod
     from backend.apps.agents.core import ws_manager as ws_mod
     from backend.apps.agents.core.models import AgentSession
 
+    monkeypatch.setattr(dash_mod, "load_all", lambda: [], raising=True)
     broadcasts = []
 
     async def p_launch(config):