diff --git a/backend/tests/test_doctor.py b/backend/tests/test_doctor.py
index 556177e78..97c0ba97d 100644
--- a/backend/tests/test_doctor.py
+++ b/backend/tests/test_doctor.py
@@ -187,6 +187,14 @@ class TestCheckModelsConfigured:
         result = doctor.check_models_configured(tmp_path / "config.yaml")
         assert result.status == "skip"
 
+    def test_commented_out_models_block(self, tmp_path):
+        # config.example.yaml ships a `models:` key whose entries are all
+        # commented out, so it parses as None rather than an empty list.
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text("config_version: 5\nmodels:\n  # - name: default\n")
+        result = doctor.check_models_configured(cfg)
+        assert result.status == "fail"
+
 
 # ---------------------------------------------------------------------------
 # check_llm_api_key
@@ -216,6 +224,14 @@ class TestCheckLLMApiKey:
         results = doctor.check_llm_api_key(tmp_path / "config.yaml")
         assert results == []
 
+    def test_commented_out_models_block_returns_empty(self, tmp_path):
+        # Regression: iterating a null `models:` raised TypeError, which the
+        # broad handler rendered as "('NoneType' object is not iterable)".
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text("config_version: 5\nmodels:\n  # - name: default\n")
+        results = doctor.check_llm_api_key(cfg)
+        assert results == []
+
 
 # ---------------------------------------------------------------------------
 # check_llm_auth
@@ -237,6 +253,12 @@ class TestCheckLLMAuth:
         results = doctor.check_llm_auth(cfg)
         assert any(result.status == "ok" and "Claude auth available" in result.label for result in results)
 
+    def test_commented_out_models_block_returns_empty(self, tmp_path):
+        cfg = tmp_path / "config.yaml"
+        cfg.write_text("config_version: 5\nmodels:\n  # - name: default\n")
+        assert doctor.check_llm_auth(cfg) == []
+        assert doctor.check_llm_package(cfg) == []
+
 
 # ---------------------------------------------------------------------------
 # check_web_search
diff --git a/scripts/doctor.py b/scripts/doctor.py
index 79c2728b3..b2830fd3b 100644
--- a/scripts/doctor.py
+++ b/scripts/doctor.py
@@ -280,7 +280,7 @@ def check_models_configured(config_path: Path) -> CheckResult:
         return CheckResult("models configured", "skip")
     try:
         data = _load_yaml_file(config_path)
-        models = data.get("models", [])
+        models = data.get("models") or []
         if models:
             return CheckResult("models configured", "ok", f"{len(models)} model(s)")
         return CheckResult(
@@ -326,7 +326,7 @@ def check_llm_api_key(config_path: Path) -> list[CheckResult]:
         with open(config_path, encoding="utf-8") as f:
             data = yaml.safe_load(f) or {}
 
-        for model in data.get("models", []):
+        for model in data.get("models") or []:
             # Collect all values that look like $ENV_VAR references
             def _collect_env_refs(obj: object) -> list[str]:
                 refs: list[str] = []
@@ -373,7 +373,7 @@ def check_llm_package(config_path: Path) -> list[CheckResult]:
             data = yaml.safe_load(f) or {}
 
         seen_packages: set[str] = set()
-        for model in data.get("models", []):
+        for model in data.get("models") or []:
             use = model.get("use", "")
             if ":" in use:
                 package_path = use.split(":")[0]
@@ -408,7 +408,7 @@ def check_llm_auth(config_path: Path) -> list[CheckResult]:
     results: list[CheckResult] = []
     try:
         data = _load_yaml_file(config_path)
-        for model in data.get("models", []):
+        for model in data.get("models") or []:
             use = model.get("use", "")
             model_name = model.get("name", "default")