fix(provider): honor ANTHROPIC_BASE_URL in native Anthropic provider

README.md

@@ -178,7 +178,7 @@ inference gateways.
 | Provider (`SKILLSPECTOR_PROVIDER`) | Credential env var | Endpoint | Default model |
 | ---------- | ---- | ---- | ---- |
 | `openai` | `OPENAI_API_KEY` (+ optional `OPENAI_BASE_URL`) | api.openai.com (or any OpenAI-compatible URL) | `gpt-5.4` |
-| `anthropic` | `ANTHROPIC_API_KEY` | api.anthropic.com | `claude-opus-4-6` |
+| `anthropic` | `ANTHROPIC_API_KEY` (+ optional `ANTHROPIC_BASE_URL`) | api.anthropic.com or override | `claude-opus-4-6` |
 | `anthropic_proxy` | `ANTHROPIC_PROXY_API_KEY` + `ANTHROPIC_PROXY_ENDPOINT_URL` | Any Vertex-style raw-predict proxy | `claude-sonnet-4-6` |
 | `nv_build` | `NVIDIA_INFERENCE_KEY` | build.nvidia.com | `deepseek-ai/deepseek-v4-flash` |
 
@@ -483,6 +483,7 @@ Issues (2)
 | `OPENAI_API_KEY` | Credential for the OpenAI provider (`SKILLSPECTOR_PROVIDER=openai`). Also serves as the tier-2 fallback in the credential waterfall when the active provider returns no credentials. | Required for LLM analysis when `SKILLSPECTOR_PROVIDER=openai` |
 | `OPENAI_BASE_URL` | Override the OpenAI endpoint (e.g. point at Ollama). | Optional |
 | `ANTHROPIC_API_KEY` | Credential for the Anthropic provider (`SKILLSPECTOR_PROVIDER=anthropic`). | Required for LLM analysis when `SKILLSPECTOR_PROVIDER=anthropic` |
+| `ANTHROPIC_BASE_URL` | Override the Anthropic endpoint. | Optional |
 | `ANTHROPIC_PROXY_ENDPOINT_URL` | Full endpoint URL for the Anthropic proxy provider (Vertex-style raw-predict). | Required when `SKILLSPECTOR_PROVIDER=anthropic_proxy` |
 | `ANTHROPIC_PROXY_API_KEY` | Bearer token for the Anthropic proxy provider. | Required when `SKILLSPECTOR_PROVIDER=anthropic_proxy` |
 | `ANTHROPIC_PROXY_API_VERSION` | `anthropic_version` value sent in the request body (default: `vertex-2023-10-16`). | Optional |

src/skillspector/providers/anthropic/provider.py

@@ -15,10 +15,10 @@
 
 """Anthropic provider — Claude models via api.anthropic.com.
 
-Reads ``ANTHROPIC_API_KEY`` for credentials and constructs
-``langchain_anthropic.ChatAnthropic`` directly. Defaults to Opus 4.6 for
-analyzers and Sonnet 4.6 for ``meta_analyzer`` (cheaper for the
-high-volume filter pass), mirroring the policy used by
+Reads ``ANTHROPIC_API_KEY`` for credentials and honors
+``ANTHROPIC_BASE_URL`` as an explicit endpoint override.
+Defaults to Opus 4.6 for analyzers and Sonnet 4.6 for ``meta_analyzer``
+(cheaper for the high-volume filter pass), mirroring the policy used by
 ``NvInferenceProvider``.
 """
 
@@ -48,11 +48,12 @@ class AnthropicProvider:
     }
 
     def resolve_credentials(self) -> tuple[str, str | None] | None:
-        """Return ``(api_key, base_url)`` from ``ANTHROPIC_API_KEY``."""
+        """Return ``(api_key, base_url)`` from ``ANTHROPIC_API_KEY`` / ``ANTHROPIC_BASE_URL``."""
         api_key = os.environ.get("ANTHROPIC_API_KEY", "").strip()
         if not api_key:
             return None
-        return api_key, None
+        base_url = os.environ.get("ANTHROPIC_BASE_URL", "").strip() or None
+        return api_key, base_url
 
     def create_chat_model(
         self,
@@ -66,11 +67,11 @@ def create_chat_model(
         if creds is None:
             return None
 
-        api_key, _ = creds
+        api_key, base_url = creds
         return ChatAnthropic(
             model_name=model,
             api_key=SecretStr(api_key),
-            base_url=ANTHROPIC_BASE_URL,
+            base_url=base_url or ANTHROPIC_BASE_URL,
             max_tokens_to_sample=max_tokens,
             timeout=timeout,
             stop=None,

tests/provider/test_provider_endpoint.py

@@ -71,11 +71,15 @@ def test_openai_provider_makes_live_structured_request(
     assert result == ProviderResult(ok=True)
 
 
-def test_anthropic_provider_makes_live_structured_request() -> None:
+def test_anthropic_provider_makes_live_structured_request(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
     """Anthropic provider reaches its default endpoint and returns structured output."""
     from skillspector.providers.anthropic import ANTHROPIC_BASE_URL, AnthropicProvider
 
     _skip_without_env("ANTHROPIC_API_KEY")
+    # This live provider check must hit Anthropic's default base URL, not a proxy.
+    monkeypatch.delenv("ANTHROPIC_BASE_URL", raising=False)
 
     model = _model_from_env("SKILLSPECTOR_ANTHROPIC_TEST_MODEL", AnthropicProvider.DEFAULT_MODEL)
     llm = AnthropicProvider().create_chat_model(model, max_tokens=32, timeout=60)

tests/unit/test_llm_utils.py

@@ -40,6 +40,7 @@
 
 _LLM_ENV_VARS = (
     "ANTHROPIC_API_KEY",
+    "ANTHROPIC_BASE_URL",
     "OPENAI_API_KEY",
     "OPENAI_BASE_URL",
     "NVIDIA_INFERENCE_KEY",
@@ -96,10 +97,11 @@ def test_anthropic_provider_wins_with_native_credentials(
     ) -> None:
         monkeypatch.setenv("SKILLSPECTOR_PROVIDER", "anthropic")
         monkeypatch.setenv("ANTHROPIC_API_KEY", "sk-ant-x")
+        monkeypatch.setenv("ANTHROPIC_BASE_URL", "http://anthropic.example/v1")
         monkeypatch.setenv("OPENAI_API_KEY", "openai-key")
         key, base = _resolve_llm_credentials()
         assert key == "sk-ant-x"
-        assert base is None
+        assert base == "http://anthropic.example/v1"
 
     def test_no_credentials_raises_with_helpful_message(self) -> None:
         with pytest.raises(ValueError) as exc_info:

tests/unit/test_providers.py

@@ -66,6 +66,7 @@ def _clean_provider_env(monkeypatch: pytest.MonkeyPatch):
     monkeypatch.delenv("OPENAI_BASE_URL", raising=False)
     monkeypatch.delenv("OPENAI_PROJECT_ID", raising=False)
     monkeypatch.delenv("ANTHROPIC_API_KEY", raising=False)
+    monkeypatch.delenv("ANTHROPIC_BASE_URL", raising=False)
     monkeypatch.delenv("SKILLSPECTOR_MODEL", raising=False)
     monkeypatch.delenv("SKILLSPECTOR_MODEL_REGISTRY", raising=False)
     monkeypatch.delenv("SKILLSPECTOR_PROVIDER", raising=False)
@@ -248,12 +249,32 @@ def test_resolves_anthropic_api_key_without_openai_endpoint(
         creds = AnthropicProvider().resolve_credentials()
         assert creds == ("sk-ant-x", None)
 
-    def test_creates_native_chat_anthropic(self, monkeypatch: pytest.MonkeyPatch) -> None:
+    def test_resolves_anthropic_base_url_override(self, monkeypatch: pytest.MonkeyPatch) -> None:
         monkeypatch.setenv("ANTHROPIC_API_KEY", "sk-ant-x")
+        monkeypatch.setenv("ANTHROPIC_BASE_URL", "http://anthropic.example/v1")
+        creds = AnthropicProvider().resolve_credentials()
+        assert creds == ("sk-ant-x", "http://anthropic.example/v1")
+
+    def test_creates_native_chat_anthropic_with_default_base_url(
+        self, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        monkeypatch.setenv("ANTHROPIC_API_KEY", "sk-ant-x")
+        llm = AnthropicProvider().create_chat_model("claude-opus-4-6", max_tokens=123)
+        assert isinstance(llm, ChatAnthropic)
+        assert llm.model == "claude-opus-4-6"
+        assert llm.max_tokens == 123
+        assert str(llm.anthropic_api_url).rstrip("/") == "https://api.anthropic.com"
+
+    def test_creates_native_chat_anthropic_with_base_url_override(
+        self, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        monkeypatch.setenv("ANTHROPIC_API_KEY", "sk-ant-x")
+        monkeypatch.setenv("ANTHROPIC_BASE_URL", "http://anthropic.example/v1")
         llm = AnthropicProvider().create_chat_model("claude-opus-4-6", max_tokens=123)
         assert isinstance(llm, ChatAnthropic)
         assert llm.model == "claude-opus-4-6"
         assert llm.max_tokens == 123
+        assert str(llm.anthropic_api_url).rstrip("/") == "http://anthropic.example/v1"
 
     def test_create_chat_model_returns_none_without_key(self) -> None:
         # No ANTHROPIC_API_KEY → no client, signalling the caller to fall back.