diff --git a/gateway/config.py b/gateway/config.py
index d3da3c30f..2b94d608f 100644
--- a/gateway/config.py
+++ b/gateway/config.py
@@ -412,6 +412,52 @@ class GatewayConfig:
         return self.unauthorized_dm_behavior
 
 
+def _validate_fallback_providers() -> None:
+    """Validate fallback_providers from config.yaml at gateway startup.
+
+    Checks that each entry has 'provider' and 'model' fields and logs
+    warnings for malformed entries.  This catches broken fallback chains
+    before they silently degrade into no-fallback mode.
+    """
+    try:
+        _home = get_hermes_home()
+        _config_path = _home / "config.yaml"
+        if not _config_path.exists():
+            return
+        import yaml
+        with open(_config_path, encoding="utf-8") as _f:
+            _cfg = yaml.safe_load(_f) or {}
+        fbp = _cfg.get("fallback_providers")
+        if not fbp:
+            return
+        if not isinstance(fbp, list):
+            logger.warning(
+                "fallback_providers should be a YAML list, got %s. "
+                "Fallback chain will be disabled.",
+                type(fbp).__name__,
+            )
+            return
+        for i, entry in enumerate(fbp):
+            if not isinstance(entry, dict):
+                logger.warning(
+                    "fallback_providers[%d] is not a dict (got %s). Skipping entry.",
+                    i, type(entry).__name__,
+                )
+                continue
+            if not entry.get("provider"):
+                logger.warning(
+                    "fallback_providers[%d] missing 'provider' field. Skipping entry.",
+                    i,
+                )
+            if not entry.get("model"):
+                logger.warning(
+                    "fallback_providers[%d] missing 'model' field. Skipping entry.",
+                    i,
+                )
+    except Exception:
+        pass  # Non-fatal; validation is advisory
+
+
 def load_gateway_config() -> GatewayConfig:
     """
     Load gateway configuration from multiple sources.
@@ -645,6 +691,19 @@ def load_gateway_config() -> GatewayConfig:
                 platform.value, env_name,
             )
 
+    # Warn about API Server enabled without a key (unauthenticated endpoint)
+    if Platform.API_SERVER in config.platforms:
+        api_cfg = config.platforms[Platform.API_SERVER]
+        if api_cfg.enabled and not api_cfg.extra.get("key"):
+            logger.warning(
+                "api_server is enabled but API_SERVER_KEY is not set. "
+                "The API endpoint will run unauthenticated. "
+                "Set API_SERVER_KEY in ~/.hermes/.env to secure it.",
+            )
+
+    # Validate fallback_providers structure from config.yaml
+    _validate_fallback_providers()
+
     return config
 
 
diff --git a/hermes_cli/config.py b/hermes_cli/config.py
index 45debf72f..6f2e72e68 100644
--- a/hermes_cli/config.py
+++ b/hermes_cli/config.py
@@ -1338,6 +1338,11 @@ _KNOWN_ROOT_KEYS = {
     "fallback_providers", "credential_pool_strategies", "toolsets",
     "agent", "terminal", "display", "compression", "delegation",
     "auxiliary", "custom_providers", "memory", "gateway",
+    "session_reset", "browser", "checkpoints", "smart_model_routing",
+    "voice", "stt", "tts", "human_delay", "security", "privacy",
+    "cron", "logging", "approvals", "command_allowlist", "quick_commands",
+    "personalities", "skills", "honcho", "timezone", "discord",
+    "whatsapp", "prefill_messages_file", "file_read_max_chars",
 }
 
 # Valid fields inside a custom_providers list entry
@@ -1498,6 +1503,72 @@ def validate_config_structure(config: Optional[Dict[str, Any]] = None) -> List["
                 f"Move '{key}' under the appropriate section",
             ))
 
+    # ── fallback_providers must be a list of dicts with provider + model ─
+    fbp = config.get("fallback_providers")
+    if fbp is not None:
+        if not isinstance(fbp, list):
+            issues.append(ConfigIssue(
+                "error",
+                f"fallback_providers should be a YAML list, got {type(fbp).__name__}",
+                "Change to:\n"
+                "  fallback_providers:\n"
+                "    - provider: openrouter\n"
+                "      model: google/gemini-3-flash-preview",
+            ))
+        elif fbp:
+            for i, entry in enumerate(fbp):
+                if not isinstance(entry, dict):
+                    issues.append(ConfigIssue(
+                        "warning",
+                        f"fallback_providers[{i}] is not a dict (got {type(entry).__name__})",
+                        "Each entry needs at minimum: provider, model",
+                    ))
+                    continue
+                if not entry.get("provider"):
+                    issues.append(ConfigIssue(
+                        "warning",
+                        f"fallback_providers[{i}] is missing 'provider' field — this fallback will be skipped",
+                        "Add: provider: openrouter (or another provider name)",
+                    ))
+                if not entry.get("model"):
+                    issues.append(ConfigIssue(
+                        "warning",
+                        f"fallback_providers[{i}] is missing 'model' field — this fallback will be skipped",
+                        "Add: model: google/gemini-3-flash-preview (or another model slug)",
+                    ))
+
+    # ── session_reset validation ─────────────────────────────────────────
+    session_reset = config.get("session_reset", {})
+    if isinstance(session_reset, dict):
+        idle_minutes = session_reset.get("idle_minutes")
+        if idle_minutes is not None:
+            if not isinstance(idle_minutes, (int, float)) or idle_minutes <= 0:
+                issues.append(ConfigIssue(
+                    "warning",
+                    f"session_reset.idle_minutes={idle_minutes} is invalid (must be a positive number)",
+                    "Set to a positive integer, e.g. 1440 (24 hours). Using 0 causes immediate resets.",
+                ))
+        at_hour = session_reset.get("at_hour")
+        if at_hour is not None:
+            if not isinstance(at_hour, (int, float)) or not (0 <= at_hour <= 23):
+                issues.append(ConfigIssue(
+                    "warning",
+                    f"session_reset.at_hour={at_hour} is invalid (must be 0-23)",
+                    "Set to an hour between 0 and 23, e.g. 4 for 4am",
+                ))
+
+    # ── API Server key check ─────────────────────────────────────────────
+    # If api_server is enabled via env, but no key is set, warn.
+    # This catches the "API_SERVER_KEY not configured" error from gateway logs.
+    api_server_enabled = os.getenv("API_SERVER_ENABLED", "").lower() in ("true", "1", "yes")
+    api_server_key = os.getenv("API_SERVER_KEY", "").strip()
+    if api_server_enabled and not api_server_key:
+        issues.append(ConfigIssue(
+            "warning",
+            "API_SERVER is enabled but API_SERVER_KEY is not set — the API server will run unauthenticated",
+            "Set API_SERVER_KEY in ~/.hermes/.env to secure the API endpoint",
+        ))
+
     return issues
 
 
diff --git a/tests/hermes_cli/test_config_validation.py b/tests/hermes_cli/test_config_validation.py
index b2435e585..43fd31856 100644
--- a/tests/hermes_cli/test_config_validation.py
+++ b/tests/hermes_cli/test_config_validation.py
@@ -249,3 +249,111 @@ class TestConfigIssueDataclass:
         a = ConfigIssue("error", "msg", "hint")
         b = ConfigIssue("error", "msg", "hint")
         assert a == b
+
+
+class TestFallbackProvidersValidation:
+    """fallback_providers must be a list of dicts with provider + model."""
+
+    def test_non_list(self):
+        """fallback_providers as string should error."""
+        issues = validate_config_structure({
+            "fallback_providers": "openrouter:google/gemini-3-flash-preview",
+        })
+        errors = [i for i in issues if i.severity == "error"]
+        assert any("fallback_providers" in i.message and "list" in i.message for i in errors)
+
+    def test_dict_instead_of_list(self):
+        """fallback_providers as dict should error."""
+        issues = validate_config_structure({
+            "fallback_providers": {"provider": "openrouter", "model": "test"},
+        })
+        errors = [i for i in issues if i.severity == "error"]
+        assert any("fallback_providers" in i.message and "dict" in i.message for i in errors)
+
+    def test_entry_missing_provider(self):
+        """Entry without provider should warn."""
+        issues = validate_config_structure({
+            "fallback_providers": [{"model": "google/gemini-3-flash-preview"}],
+        })
+        assert any("missing 'provider'" in i.message for i in issues)
+
+    def test_entry_missing_model(self):
+        """Entry without model should warn."""
+        issues = validate_config_structure({
+            "fallback_providers": [{"provider": "openrouter"}],
+        })
+        assert any("missing 'model'" in i.message for i in issues)
+
+    def test_entry_not_dict(self):
+        """Non-dict entries should warn."""
+        issues = validate_config_structure({
+            "fallback_providers": ["not-a-dict"],
+        })
+        assert any("not a dict" in i.message for i in issues)
+
+    def test_valid_entries(self):
+        """Valid fallback_providers should produce no fallback-related issues."""
+        issues = validate_config_structure({
+            "fallback_providers": [
+                {"provider": "openrouter", "model": "google/gemini-3-flash-preview"},
+                {"provider": "gemini", "model": "gemini-2.5-flash"},
+            ],
+        })
+        fb_issues = [i for i in issues if "fallback_providers" in i.message]
+        assert len(fb_issues) == 0
+
+    def test_empty_list_no_issues(self):
+        """Empty list is valid (fallback disabled)."""
+        issues = validate_config_structure({
+            "fallback_providers": [],
+        })
+        fb_issues = [i for i in issues if "fallback_providers" in i.message]
+        assert len(fb_issues) == 0
+
+
+class TestSessionResetValidation:
+    """session_reset.idle_minutes must be positive."""
+
+    def test_zero_idle_minutes(self):
+        """idle_minutes=0 should warn."""
+        issues = validate_config_structure({
+            "session_reset": {"idle_minutes": 0},
+        })
+        assert any("idle_minutes=0" in i.message for i in issues)
+
+    def test_negative_idle_minutes(self):
+        """idle_minutes=-5 should warn."""
+        issues = validate_config_structure({
+            "session_reset": {"idle_minutes": -5},
+        })
+        assert any("idle_minutes=-5" in i.message for i in issues)
+
+    def test_string_idle_minutes(self):
+        """idle_minutes as string should warn."""
+        issues = validate_config_structure({
+            "session_reset": {"idle_minutes": "abc"},
+        })
+        assert any("idle_minutes=" in i.message for i in issues)
+
+    def test_valid_idle_minutes(self):
+        """Valid idle_minutes should not warn."""
+        issues = validate_config_structure({
+            "session_reset": {"idle_minutes": 1440},
+        })
+        idle_issues = [i for i in issues if "idle_minutes" in i.message]
+        assert len(idle_issues) == 0
+
+    def test_invalid_at_hour(self):
+        """at_hour=25 should warn."""
+        issues = validate_config_structure({
+            "session_reset": {"at_hour": 25},
+        })
+        assert any("at_hour=25" in i.message for i in issues)
+
+    def test_valid_at_hour(self):
+        """Valid at_hour should not warn."""
+        issues = validate_config_structure({
+            "session_reset": {"at_hour": 4},
+        })
+        hour_issues = [i for i in issues if "at_hour" in i.message]
+        assert len(hour_issues) == 0