feat(you_com): prefer YDC_API_KEY env var (keep YOUCOM_API_KEY fallback)

YDC_API_KEY is You.com's canonical API key env var (used by its own docs,
SDK, and the LangChain/CrewAI/DSPy integrations). The you_com search provider
previously only read YOUCOM_API_KEY. This makes YDC_API_KEY the preferred
name while keeping YOUCOM_API_KEY as a backward-compatible fallback, so
existing configs keep working.

- resolve_server_api_key now reads ("YDC_API_KEY", "YOUCOM_API_KEY") in order
- get_complete_url checks YDC_API_KEY before YOUCOM_API_KEY
- example config comment updated to YDC_API_KEY
- tests: YDC takes precedence over legacy key; legacy key still works

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

litellm/llms/you_com/search/transformation.py

@@ -43,7 +43,7 @@ class YouComSearchConfig(BaseSearchConfig):
     # Keyed tier (higher rate limits): authenticate with X-API-Key.
     YOU_COM_API_BASE = "https://ydc-index.io"
     # Keyless free tier: IP-throttled (100 queries/day) and requires no auth.
-    # Used automatically when YOUCOM_API_KEY is not set.
+    # Used automatically when no API key (YDC_API_KEY / YOUCOM_API_KEY) is set.
     YOU_COM_FREE_API_BASE = "https://api.you.com/v1/agents/search"
 
     @staticmethod
@@ -60,14 +60,15 @@ class YouComSearchConfig(BaseSearchConfig):
         """
         Set headers for the You.com Search API.
 
-        If YOUCOM_API_KEY (or an explicit api_key) is present, use the keyed
-        endpoint with the `X-API-Key` header. Otherwise fall through to the
-        keyless free tier; no auth header is required.
+        If an API key is present (YDC_API_KEY, the legacy YOUCOM_API_KEY, or an
+        explicit api_key), use the keyed endpoint with the `X-API-Key` header.
+        Otherwise fall through to the keyless free tier; no auth header is
+        required.
         """
         api_key = self.resolve_server_api_key(
             caller_api_key=api_key,
             caller_api_base=api_base,
-            key_env_vars=("YOUCOM_API_KEY",),
+            key_env_vars=("YDC_API_KEY", "YOUCOM_API_KEY"),
             base_env_var="YOUCOM_API_BASE",
             default_api_base=self.YOU_COM_API_BASE,
         )
@@ -92,14 +93,18 @@ class YouComSearchConfig(BaseSearchConfig):
         Pick the endpoint based on whether an API key is configured.
 
         - api_base explicit override     -> use it as-is (normalized)
-        - YOUCOM_API_KEY set             -> keyed endpoint (ydc-index.io/v1/search)
+        - YDC_API_KEY / YOUCOM_API_KEY   -> keyed endpoint (ydc-index.io/v1/search)
         - no key                         -> keyless free tier (api.you.com/v1/agents/search)
         """
         if api_base is None:
             api_base = get_secret_str("YOUCOM_API_BASE")
 
         if api_base is None:
-            api_key = kwargs.get("api_key") or get_secret_str("YOUCOM_API_KEY")
+            api_key = (
+                kwargs.get("api_key")
+                or get_secret_str("YDC_API_KEY")
+                or get_secret_str("YOUCOM_API_KEY")
+            )
             if api_key:
                 api_base = self.YOU_COM_API_BASE
             else:

litellm/proxy/example_config_yaml/websearch_interception_config.yaml

@@ -8,7 +8,7 @@ search_tools:
   - search_tool_name: "my-perplexity-search"
     litellm_params:
       search_provider: "perplexity"
-  # Alternative provider example (requires YOUCOM_API_KEY):
+  # Alternative provider example (requires YDC_API_KEY):
   # - search_tool_name: "my-you-com-search"
   #   litellm_params:
   #     search_provider: "you_com"

tests/test_litellm/llms/you_com/test_you_com_search.py

@@ -20,9 +20,11 @@ class TestYouComSearch:
     @pytest.fixture(autouse=True)
     def _set_api_key(self, monkeypatch):
         """
-        Default fixture: YOUCOM_API_KEY is set, scoped to this test.
-        Tests that need the key absent should call `monkeypatch.delenv` themselves.
+        Default fixture: the canonical YDC_API_KEY is cleared and the legacy
+        YOUCOM_API_KEY is set, scoped to this test. Tests that need the key
+        absent should call `monkeypatch.delenv` themselves.
         """
+        monkeypatch.delenv("YDC_API_KEY", raising=False)
         monkeypatch.setenv("YOUCOM_API_KEY", "test-api-key")
 
     @pytest.mark.asyncio
@@ -328,6 +330,71 @@ class TestYouComSearch:
             headers = call_args.kwargs.get("headers", {})
             assert headers["X-API-Key"] == "my-programmatic-key"
 
+    @pytest.mark.asyncio
+    async def test_you_com_search_prefers_ydc_api_key_over_legacy(self, monkeypatch):
+        """
+        YDC_API_KEY is the canonical env var and must take precedence over the
+        legacy YOUCOM_API_KEY when both are set: the keyed endpoint is selected
+        and X-API-Key carries the YDC_API_KEY value.
+        """
+        monkeypatch.setenv("YDC_API_KEY", "ydc-key")
+        monkeypatch.setenv("YOUCOM_API_KEY", "legacy-key")
+
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {
+            "results": {"web": [], "news": []},
+            "metadata": {},
+        }
+
+        with patch(
+            "litellm.llms.custom_httpx.http_handler.AsyncHTTPHandler.post",
+            new_callable=AsyncMock,
+        ) as mock_post:
+            mock_post.return_value = mock_response
+
+            await litellm.asearch(
+                query="anything",
+                search_provider="you_com",
+            )
+
+            call_args = mock_post.call_args
+            assert call_args.kwargs["url"] == "https://ydc-index.io/v1/search"
+            headers = call_args.kwargs.get("headers", {})
+            assert headers["X-API-Key"] == "ydc-key"
+
+    @pytest.mark.asyncio
+    async def test_you_com_search_legacy_youcom_api_key_still_works(self, monkeypatch):
+        """
+        Backwards compatibility: with only the legacy YOUCOM_API_KEY set (and
+        YDC_API_KEY absent), the keyed endpoint is still selected.
+        """
+        monkeypatch.delenv("YDC_API_KEY", raising=False)
+        monkeypatch.setenv("YOUCOM_API_KEY", "legacy-key")
+
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {
+            "results": {"web": [], "news": []},
+            "metadata": {},
+        }
+
+        with patch(
+            "litellm.llms.custom_httpx.http_handler.AsyncHTTPHandler.post",
+            new_callable=AsyncMock,
+        ) as mock_post:
+            mock_post.return_value = mock_response
+
+            await litellm.asearch(
+                query="anything",
+                search_provider="you_com",
+            )
+
+            call_args = mock_post.call_args
+            assert call_args.kwargs["url"] == "https://ydc-index.io/v1/search"
+            headers = call_args.kwargs.get("headers", {})
+            assert headers["X-API-Key"] == "legacy-key"
+
     def test_you_com_search_complete_url_uses_programmatic_api_key(self, monkeypatch):
         """
         get_complete_url selects the keyed endpoint from a forwarded api_key even