Surface YOLO preflight in Detection Lab

backend/README.md

@@ -301,6 +301,12 @@ python scripts/yolo_preflight.py --model-path /absolute/path/to/local-model.pt -
 
 The preflight checks configuration, dependency availability, local model file existence, tile manifest validity, tile count and referenced tile paths. JSON output also includes runtime diagnostics for the model directory, `YOLO_CONFIG_DIR`, installed `torch`/`ultralytics` versions and CUDA availability when dependency checks pass. It does not load a YOLO model, run inference or download weights.
 
+The same read-only status is available through the API and Detection Lab UI:
+
+```bash
+curl http://localhost:1202/api/v1/detection/yolo/preflight
+```
+
 ### Run backend
 
 ```bash

backend/app/api/routes/detection.py

@@ -9,6 +9,7 @@ from app.db.session import get_db
 from app.schemas import DetectionQaRequest, DetectionRunRequest
 from app.services.detection_service import DetectionService
 from app.services.model_registry_service import ModelRegistryService
+from app.services.yolo_preflight_service import YoloPreflightService
 from app.utils.response import envelope
 
 router = APIRouter(prefix="/detection", tags=["detection"])
@@ -19,6 +20,16 @@ def list_detection_models() -> dict:
     return envelope({"models": [model.model_dump() for model in ModelRegistryService.list_model_capabilities()]})
 
 
+@router.get("/yolo/preflight", response_model=dict)
+def get_yolo_preflight(tile_manifest_path: str | None = None, check_model_load: bool = False) -> dict:
+    return envelope(
+        YoloPreflightService.run(
+            tile_manifest_path=tile_manifest_path,
+            check_model_load=check_model_load,
+        )
+    )
+
+
 @router.post("/run", response_model=dict)
 def run_detection(payload: DetectionRunRequest, db: Session = Depends(get_db)) -> dict:
     result = DetectionService.run_detection(

backend/tests/test_sprint118_yolo_preflight_ui.py

@@ -0,0 +1,25 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[2]
+
+
+def test_detection_lab_surfaces_yolo_runtime_preflight() -> None:
+    lab = (ROOT / "frontend" / "src" / "components" / "detection" / "DetectionLab.tsx").read_text(
+        encoding="utf-8"
+    )
+    hook = (ROOT / "frontend" / "src" / "hooks" / "useDetectionWorkflow.ts").read_text(encoding="utf-8")
+    api = (ROOT / "frontend" / "src" / "services" / "api" / "detection.ts").read_text(encoding="utf-8")
+    types = (ROOT / "frontend" / "src" / "types.ts").read_text(encoding="utf-8")
+    app = (ROOT / "frontend" / "src" / "App.tsx").read_text(encoding="utf-8")
+
+    assert "YOLO runtime preflight" in lab
+    assert "torch_version" in lab
+    assert "ultralytics_version" in lab
+    assert "cuda_available" in lab
+    assert "onRefreshYoloPreflight" in lab
+    assert "loadYoloPreflight" in hook
+    assert "getYoloPreflight" in api
+    assert "/api/v1/detection/yolo/preflight" in api
+    assert "interface YoloPreflightResponse" in types
+    assert "yoloPreflight={yoloPreflight}" in app

backend/tests/test_sprint13_yolo_preflight.py

@@ -5,7 +5,10 @@ import subprocess
 import sys
 from pathlib import Path
 
+from fastapi.testclient import TestClient
+
 from app.core.config import Settings
+from app.main import app
 from app.services.yolo_preflight_service import YoloPreflightService
 
 
@@ -213,3 +216,21 @@ def test_yolo_preflight_script_rejects_assumed_dependencies_for_model_load(tmp_p
 
     assert result.returncode != 0
     assert "--check-model-load cannot be combined with --assume-dependencies" in result.stderr
+
+
+def test_yolo_preflight_api_returns_canonical_envelope(monkeypatch, tmp_path: Path) -> None:
+    monkeypatch.setenv("YOLO_ENABLED", "false")
+    monkeypatch.setenv("YOLO_MODEL_PATH", str(tmp_path / "missing.pt"))
+    monkeypatch.setenv("YOLO_CONFIG_DIR", str(tmp_path / "ultralytics"))
+
+    response = TestClient(app).get("/api/v1/detection/yolo/preflight")
+
+    assert response.status_code == 200
+    payload = response.json()
+    assert set(payload) == {"data"}
+    assert payload["data"]["status"] == "not_configured"
+    assert payload["data"]["checks"]["enabled"] is False
+    assert payload["data"]["runtime"]["model_directory"] == str(tmp_path)
+    assert payload["data"]["runtime"]["yolo_config_dir"] == str(tmp_path / "ultralytics")
+    assert payload["data"]["will_download_models"] is False
+    assert payload["data"]["will_run_inference"] is False