fix(gateway): tolerate scalar gateway config block

The streaming fallback path read yaml_cfg.get("gateway", {}).get("streaming") when top-level streaming was absent or malformed. If a user accidentally set gateway to a scalar value, config loading crashed with AttributeError instead of ignoring the malformed block and using defaults.

Read the gateway block once, verify it is a mapping before accessing nested streaming, and keep the existing gateway.platforms fallback using the same checked value.

Adds a regression test for config.yaml containing gateway: disabled.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

gateway/config.py

@@ -1039,6 +1039,8 @@ def load_gateway_config() -> GatewayConfig:
             if "stt_echo_transcripts" in yaml_cfg:
                 gw_data["stt_echo_transcripts"] = yaml_cfg["stt_echo_transcripts"]
 
+            gateway_cfg = yaml_cfg.get("gateway")
+
             if "group_sessions_per_user" in yaml_cfg:
                 gw_data["group_sessions_per_user"] = yaml_cfg["group_sessions_per_user"]
 
@@ -1066,7 +1068,11 @@ def load_gateway_config() -> GatewayConfig:
             if not isinstance(streaming_cfg, dict):
                 # Fall back to nested gateway.streaming written by
                 # ``hermes config set gateway.streaming.*``
-                streaming_cfg = yaml_cfg.get("gateway", {}).get("streaming")
+                streaming_cfg = (
+                    gateway_cfg.get("streaming")
+                    if isinstance(gateway_cfg, dict)
+                    else None
+                )
             if isinstance(streaming_cfg, dict):
                 gw_data["streaming"] = streaming_cfg
 
@@ -1099,7 +1105,6 @@ def load_gateway_config() -> GatewayConfig:
             # ``gateway.platforms`` are loaded the same way as top-level
             # ``platforms``. Merge nested first so top-level config keeps
             # precedence, matching the existing gateway.streaming fallback.
-            gateway_cfg = yaml_cfg.get("gateway")
             gateway_platforms = gateway_cfg.get("platforms") if isinstance(gateway_cfg, dict) else None
             platforms_data = gw_data.setdefault("platforms", {})
             if not isinstance(platforms_data, dict):

tests/gateway/test_config.py

@@ -608,6 +608,18 @@ class TestLoadGatewayConfig:
 
         assert config.max_concurrent_sessions == 2
 
+    def test_scalar_gateway_section_does_not_crash_streaming_fallback(self, tmp_path, monkeypatch):
+        hermes_home = tmp_path / ".hermes"
+        hermes_home.mkdir()
+        config_path = hermes_home / "config.yaml"
+        config_path.write_text("gateway: disabled\n", encoding="utf-8")
+
+        monkeypatch.setenv("HERMES_HOME", str(hermes_home))
+
+        config = load_gateway_config()
+
+        assert config.streaming.transport == "auto"
+
     def test_bridges_discord_thread_require_mention_from_config_yaml(self, tmp_path, monkeypatch):
         """discord.thread_require_mention in config.yaml should reach the runtime env var."""
         hermes_home = tmp_path / ".hermes"