fix(gateway): preserve max turns after env reload

gateway/run.py

@@ -299,6 +299,36 @@ _env_path = _hermes_home / '.env'
 load_hermes_dotenv(hermes_home=_hermes_home, project_env=Path(__file__).resolve().parents[1] / '.env')
 
 
+def _reload_runtime_env_preserving_config_authority() -> None:
+    """Reload .env for fresh credentials without letting stale .env override config.
+
+    Gateway processes are long-lived, so per-turn code reloads ~/.hermes/.env to
+    pick up rotated API keys. config.yaml remains authoritative for agent budget
+    settings such as agent.max_turns; otherwise a stale HERMES_MAX_ITERATIONS in
+    .env can replace the startup bridge on later turns.
+    """
+    load_hermes_dotenv(
+        hermes_home=_hermes_home,
+        project_env=Path(__file__).resolve().parents[1] / '.env',
+    )
+
+    config_path = _hermes_home / 'config.yaml'
+    if not config_path.exists():
+        return
+    try:
+        import yaml as _yaml
+        with open(config_path, encoding="utf-8") as f:
+            cfg = _yaml.safe_load(f) or {}
+        from hermes_cli.config import _expand_env_vars
+        cfg = _expand_env_vars(cfg)
+    except Exception:
+        return
+
+    agent_cfg = cfg.get("agent", {})
+    if isinstance(agent_cfg, dict) and "max_turns" in agent_cfg:
+        os.environ["HERMES_MAX_ITERATIONS"] = str(agent_cfg["max_turns"])
+
+
 _DOCKER_VOLUME_SPEC_RE = re.compile(r"^(?P<host>.+):(?P<container>/[^:]+?)(?::(?P<options>[^:]+))?$")
 _DOCKER_MEDIA_OUTPUT_CONTAINER_PATHS = {"/output", "/outputs"}
 
@@ -13524,13 +13554,9 @@ class GatewayRunner:
                 combined_ephemeral = (combined_ephemeral + "\n\n" + self._ephemeral_system_prompt).strip()
 
             # Re-read .env and config for fresh credentials (gateway is long-lived,
-            # keys may change without restart).
-            try:
-                load_dotenv(_env_path, override=True, encoding="utf-8")
-            except UnicodeDecodeError:
-                load_dotenv(_env_path, override=True, encoding="latin-1")
-            except Exception:
-                pass
+            # keys may change without restart). Keep config.yaml authoritative for
+            # runtime budget settings bridged into env vars.
+            _reload_runtime_env_preserving_config_authority()
 
             try:
                 model, runtime_kwargs = self._resolve_session_agent_runtime(

tests/gateway/test_runtime_env_reload_config_authority.py

@@ -0,0 +1,53 @@
+"""Regression tests for gateway per-turn env reload preserving config authority.
+
+Issue #19158: startup bridges config.yaml agent.max_turns into
+HERMES_MAX_ITERATIONS, but a later per-turn load_dotenv(..., override=True)
+can restore a stale .env HERMES_MAX_ITERATIONS value before the next turn.
+"""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+import yaml
+
+from gateway import run as gateway_run
+
+
+def test_reload_runtime_env_preserves_config_max_turns(tmp_path: Path, monkeypatch) -> None:
+    hermes_home = tmp_path / ".hermes"
+    hermes_home.mkdir()
+    (hermes_home / "config.yaml").write_text(
+        yaml.safe_dump({"agent": {"max_turns": 9000}}),
+        encoding="utf-8",
+    )
+    (hermes_home / ".env").write_text(
+        "HERMES_MAX_ITERATIONS=90\nOPENROUTER_API_KEY=fresh-key\n",
+        encoding="utf-8",
+    )
+
+    monkeypatch.setattr(gateway_run, "_hermes_home", hermes_home)
+    monkeypatch.setenv("HERMES_MAX_ITERATIONS", "9000")
+    monkeypatch.delenv("OPENROUTER_API_KEY", raising=False)
+
+    gateway_run._reload_runtime_env_preserving_config_authority()
+
+    assert os.environ["OPENROUTER_API_KEY"] == "fresh-key"
+    assert os.environ["HERMES_MAX_ITERATIONS"] == "9000"
+
+
+def test_reload_runtime_env_keeps_env_max_iterations_when_config_omits_key(
+    tmp_path: Path, monkeypatch
+) -> None:
+    hermes_home = tmp_path / ".hermes"
+    hermes_home.mkdir()
+    (hermes_home / "config.yaml").write_text(yaml.safe_dump({"agent": {}}), encoding="utf-8")
+    (hermes_home / ".env").write_text("HERMES_MAX_ITERATIONS=123\n", encoding="utf-8")
+
+    monkeypatch.setattr(gateway_run, "_hermes_home", hermes_home)
+    monkeypatch.delenv("HERMES_MAX_ITERATIONS", raising=False)
+
+    gateway_run._reload_runtime_env_preserving_config_authority()
+
+    assert os.environ["HERMES_MAX_ITERATIONS"] == "123"