Upload folder using huggingface_hub

app.py

@@ -97,6 +97,27 @@ async def _pulse(coro, holder, message, interval: int = 9):
         yield _ev(type="commentary", text=f"{message} ({int(time.monotonic() - start)}s)")
 
 
+# Cached per-boot preflight (N35). Fail-fast ONLY on genuinely-doomed config
+# (missing SerpApi key — build_trip_packages cannot fetch live flights/hotels).
+# Modal cold-start is NOT a hard failure: it streams via _pulse heartbeats and
+# the loop degrades to the deterministic parser, so we don't gate on it.
+_PREFLIGHT_OK: bool | None = None
+
+
+def _preflight() -> tuple[bool, str]:
+    """Return (ok, reason). ``reason`` is empty when ok. Cached positive."""
+    global _PREFLIGHT_OK
+    if _PREFLIGHT_OK:
+        return True, ""
+    if not os.environ.get("SERPAPI_API_KEY"):
+        return False, (
+            "SerpApi key is not set on this Space — live flight & hotel search is "
+            "unavailable. Add SERPAPI_API_KEY in Settings → Secrets, then restart."
+        )
+    _PREFLIGHT_OK = True
+    return True, ""
+
+
 async def _agent_explain(agent, user_text: str, trip: TripRequest, result) -> str:
     """Round 2 — Nemotron compares the packages. Best-effort ('' on failure)."""
     args_json = json.dumps(trip.model_dump(mode="json"))
@@ -136,6 +157,11 @@ async def plan_trip(user_text: str) -> str:
     + Nemotron's explanation). Falls back to the deterministic parser if the
     agent is unavailable or hedges.
     """
+    ok, why = _preflight()  # N35 — fail-fast on doomed config (missing key)
+    if not ok:
+        yield _ev(type="error", text=f"⚠️ {why}")
+        return
+
     yield _ev(type="commentary", text="Reading your trip request…")
 
     agent = None