diff --git a/navi/api/routes/synapse.py b/navi/api/routes/synapse.py
index 90b978a..cc07a9a 100644
--- a/navi/api/routes/synapse.py
+++ b/navi/api/routes/synapse.py
@@ -22,6 +22,7 @@
 
 from navi.api.deps import require_user
 from navi.auth import User
+from navi.synapse.outbound import synapse_source_ready
 from navi.synapse.settings_store import (
     CompletionNotify,
     PushTarget,
@@ -189,7 +190,10 @@
 ) -> dict:
     store = SynapseSettingsStore(await _pool())
     settings_row = await store.get(user.id)
-    return settings_row.model_dump(mode="json", exclude={"user_id"})
+    data = settings_row.model_dump(mode="json", exclude={"user_id"})
+    # Not persisted — tells the UI whether Synapse-linked options are usable.
+    data["source_ready"] = synapse_source_ready()
+    return data
 
 
 @settings_router.put("")
@@ -208,7 +212,9 @@
         )
         current.instructions = payload.instructions
     await store.save(current)
-    return current.model_dump(mode="json", exclude={"user_id"})
+    data = current.model_dump(mode="json", exclude={"user_id"})
+    data["source_ready"] = synapse_source_ready()
+    return data
 
 
 @settings_router.get("/versions")
diff --git a/tests/unit/api/test_synapse.py b/tests/unit/api/test_synapse.py
index 9673f83..20b7a6b 100644
--- a/tests/unit/api/test_synapse.py
+++ b/tests/unit/api/test_synapse.py
@@ -220,6 +220,8 @@
     assert body["push_target"] == "app"
     assert body["completion_notify"] == "important"
     assert body["instructions"] == ""
+    # tells the UI whether Synapse-linked options are usable (no keys in tests)
+    assert body["source_ready"] is False
 
 
 def test_synapse_settings_put_records_user_edit(synapse_client, monkeypatch):