fix(auxiliary): gate Anthropic base_url override on Anthropic-compatible host (#52608)

agent/auxiliary_client.py

@@ -665,6 +665,28 @@ def _pool_runtime_base_url(entry: Any, fallback: str = "") -> str:
     return str(url or "").strip().rstrip("/")
 
 
+# Hostnames (lowercase, exact) that the auxiliary Anthropic path is allowed to
+# be pointed at via config.yaml model.base_url. Anything else falls back to the
+# Anthropic default — operators routing main-session traffic through a
+# non-Anthropic host (e.g. OpenRouter, OpenAI) with provider=anthropic in config
+# must NOT have that foreign host leak into the auxiliary client. See #52608.
+_ANTHROPIC_COMPATIBLE_HOSTS = frozenset({
+    "api.anthropic.com",
+})
+
+
+def _is_anthropic_compatible_host(url: str) -> bool:
+    """Return True if ``url``'s hostname is an Anthropic endpoint we trust for aux calls."""
+    if not url:
+        return False
+    try:
+        from urllib.parse import urlparse
+        host = (urlparse(url).hostname or "").strip().lower().rstrip(".")
+        return host in _ANTHROPIC_COMPATIBLE_HOSTS
+    except Exception:
+        return False
+
+
 def _nous_min_key_ttl_seconds() -> int:
     try:
         return max(60, int(os.getenv("HERMES_NOUS_MIN_KEY_TTL_SECONDS", "1800")))
@@ -2255,9 +2277,16 @@ def _try_anthropic(explicit_api_key: str = None) -> Tuple[Optional[Any], Optiona
     if not token:
         return None, None
 
-    # Allow base URL override from config.yaml model.base_url, but only
-    # when the configured provider is anthropic — otherwise a non-Anthropic
-    # base_url (e.g. Codex endpoint) would leak into Anthropic requests.
+    # Allow base URL override from config.yaml model.base_url, but only when:
+    #   1. the configured provider is anthropic (otherwise a non-Anthropic
+    #      base_url, e.g. Codex endpoint, would leak into Anthropic requests), AND
+    #   2. the override URL actually points at an Anthropic-compatible endpoint.
+    # Without gate (2), operators who route main-session traffic through a
+    # non-Anthropic provider that accepts Anthropic-format requests (e.g.
+    # OpenRouter at openrouter.ai/api/v1, with provider=anthropic in config.yaml)
+    # would have every auxiliary side-channel call (memory extractors,
+    # reflection, vision, title generation) 401 from the foreign host —
+    # see issue #52608.
     base_url = _pool_runtime_base_url(entry, _ANTHROPIC_DEFAULT_BASE_URL) if pool_present else _ANTHROPIC_DEFAULT_BASE_URL
     try:
         from hermes_cli.config import load_config
@@ -2267,7 +2296,7 @@ def _try_anthropic(explicit_api_key: str = None) -> Tuple[Optional[Any], Optiona
             cfg_provider = str(model_cfg.get("provider") or "").strip().lower()
             if cfg_provider == "anthropic":
                 cfg_base_url = (model_cfg.get("base_url") or "").strip().rstrip("/")
-                if cfg_base_url:
+                if cfg_base_url and _is_anthropic_compatible_host(cfg_base_url):
                     base_url = cfg_base_url
     except Exception:
         pass

tests/agent/test_auxiliary_client_base_url_host_validation_52608.py

@@ -0,0 +1,189 @@
+"""Regression tests for issue #52608.
+
+auxiliary_client `_try_anthropic()` must NOT apply `cfg["model"]["base_url"]`
+when the configured base_url host is not an Anthropic-compatible endpoint
+(e.g. OpenRouter, OpenAI). Operators routing main traffic through a
+non-Anthropic provider's endpoint while keeping `provider: anthropic` would
+otherwise have every side-channel call (memory extractors, reflection,
+vision, title generation) 401 from the foreign host.
+"""
+from unittest.mock import MagicMock, patch
+
+
+def _extract_base_url_passed_to_build(mock_build):
+    """Pull the base_url that `_try_anthropic()` actually handed to build_anthropic_client."""
+    args, _kwargs = mock_build.call_args
+    # build_anthropic_client(token, base_url) per agent/auxiliary_client.py line 2180
+    assert len(args) >= 2, f"expected (token, base_url), got args={args}"
+    return args[1]
+
+
+class TestTryAnthropicBaseUrlHostValidation:
+    """Issue #52608: side-channel calls must not be sent to a non-Anthropic host."""
+
+    def test_openrouter_base_url_does_not_leak_into_auxiliary(self, tmp_path, monkeypatch):
+        """cfg.model.base_url=https://openrouter.ai/api/v1 must NOT override aux base_url."""
+        import yaml
+        from agent.auxiliary_client import _try_anthropic
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        (tmp_path / "config.yaml").write_text(yaml.safe_dump({
+            "model": {
+                "provider": "anthropic",
+                "model": "claude-haiku-4-5-20251001",
+                "base_url": "https://openrouter.ai/api/v1",
+            }
+        }))
+
+        with (
+            patch(
+                "agent.auxiliary_client._select_pool_entry", return_value=(False, None)
+            ),
+            patch(
+                "agent.anthropic_adapter.resolve_anthropic_token",
+                return_value="***",
+            ),
+            patch(
+                "agent.anthropic_adapter.build_anthropic_client"
+            ) as mock_build,
+        ):
+            mock_build.return_value = MagicMock()
+            client, _model = _try_anthropic()
+
+        assert client is not None, "auxiliary client must still be created"
+        actual = _extract_base_url_passed_to_build(mock_build)
+        assert actual == "https://api.anthropic.com", (
+            f"Auxiliary client must use the Anthropic default base_url, "
+            f"not the operator's main-session override. Got: {actual!r}"
+        )
+
+    def test_anthropic_default_host_is_preserved(self, tmp_path, monkeypatch):
+        """The common case (operator sets model.base_url to api.anthropic.com) must still apply."""
+        import yaml
+        from agent.auxiliary_client import _try_anthropic
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        (tmp_path / "config.yaml").write_text(yaml.safe_dump({
+            "model": {
+                "provider": "anthropic",
+                "model": "claude-haiku-4-5-20251001",
+                "base_url": "https://api.anthropic.com",
+            }
+        }))
+
+        with (
+            patch(
+                "agent.auxiliary_client._select_pool_entry", return_value=(False, None)
+            ),
+            patch(
+                "agent.anthropic_adapter.resolve_anthropic_token",
+                return_value="***",
+            ),
+            patch(
+                "agent.anthropic_adapter.build_anthropic_client"
+            ) as mock_build,
+        ):
+            mock_build.return_value = MagicMock()
+            client, _model = _try_anthropic()
+
+        assert client is not None
+        actual = _extract_base_url_passed_to_build(mock_build)
+        assert actual == "https://api.anthropic.com"
+
+    def test_openai_base_url_does_not_leak(self, tmp_path, monkeypatch):
+        """Generic non-Anthropic host must not be applied as auxiliary base_url."""
+        import yaml
+        from agent.auxiliary_client import _try_anthropic
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        (tmp_path / "config.yaml").write_text(yaml.safe_dump({
+            "model": {
+                "provider": "anthropic",
+                "model": "claude-haiku-4-5-20251001",
+                "base_url": "https://api.openai.com/v1",
+            }
+        }))
+
+        with (
+            patch(
+                "agent.auxiliary_client._select_pool_entry", return_value=(False, None)
+            ),
+            patch(
+                "agent.anthropic_adapter.resolve_anthropic_token",
+                return_value="***",
+            ),
+            patch(
+                "agent.anthropic_adapter.build_anthropic_client"
+            ) as mock_build,
+        ):
+            mock_build.return_value = MagicMock()
+            client, _model = _try_anthropic()
+
+        assert client is not None
+        actual = _extract_base_url_passed_to_build(mock_build)
+        assert actual == "https://api.anthropic.com", (
+            f"Non-Anthropic host must not be applied. Got: {actual!r}"
+        )
+
+    def test_empty_base_url_falls_back_to_default(self, tmp_path, monkeypatch):
+        """Empty model.base_url must not crash and must fall back to default."""
+        import yaml
+        from agent.auxiliary_client import _try_anthropic
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        (tmp_path / "config.yaml").write_text(yaml.safe_dump({
+            "model": {
+                "provider": "anthropic",
+                "model": "claude-haiku-4-5-20251001",
+                "base_url": "",
+            }
+        }))
+
+        with (
+            patch(
+                "agent.auxiliary_client._select_pool_entry", return_value=(False, None)
+            ),
+            patch(
+                "agent.anthropic_adapter.resolve_anthropic_token",
+                return_value="***",
+            ),
+            patch(
+                "agent.anthropic_adapter.build_anthropic_client"
+            ) as mock_build,
+        ):
+            mock_build.return_value = MagicMock()
+            client, _model = _try_anthropic()
+
+        assert client is not None
+        actual = _extract_base_url_passed_to_build(mock_build)
+        assert actual == "https://api.anthropic.com"
+
+    def test_anthropic_host_with_path_is_preserved(self, tmp_path, monkeypatch):
+        """api.anthropic.com with a path suffix must still pass the host check."""
+        import yaml
+        from agent.auxiliary_client import _try_anthropic
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        (tmp_path / "config.yaml").write_text(yaml.safe_dump({
+            "model": {
+                "provider": "anthropic",
+                "model": "claude-haiku-4-5-20251001",
+                "base_url": "https://api.anthropic.com/v1/messages",
+            }
+        }))
+
+        with (
+            patch(
+                "agent.auxiliary_client._select_pool_entry", return_value=(False, None)
+            ),
+            patch(
+                "agent.anthropic_adapter.resolve_anthropic_token",
+                return_value="***",
+            ),
+            patch(
+                "agent.anthropic_adapter.build_anthropic_client"
+            ) as mock_build,
+        ):
+            mock_build.return_value = MagicMock()
+            client, _model = _try_anthropic()
+
+        assert client is not None
+        actual = _extract_base_url_passed_to_build(mock_build)
+        assert actual == "https://api.anthropic.com/v1/messages", (
+            f"Anthropic host with path must be preserved. Got: {actual!r}"
+        )