diff --git a/python/packages/kagent-adk/src/kagent/adk/_a2a.py b/python/packages/kagent-adk/src/kagent/adk/_a2a.py
index 7b08e6f17..a62f00d67 100644
--- a/python/packages/kagent-adk/src/kagent/adk/_a2a.py
+++ b/python/packages/kagent-adk/src/kagent/adk/_a2a.py
@@ -52,6 +52,19 @@ def thread_dump(request: Request) -> PlainTextResponse:
 kagent_url_override = os.getenv("KAGENT_URL")
 
 
+def _configure_anthropic_client() -> None:
+    """
+    Configure the Anthropic client to use ANTHROPIC_BASE_URL.
+
+    Reads ANTHROPIC_BASE_URL from the environment (matching the Go-side
+    env.AnthropicAPIBaseURL registration) and logs its presence. The Anthropic
+    SDK natively reads ANTHROPIC_BASE_URL, so no explicit remapping is needed.
+    """
+    anthropic_api_base = os.getenv("ANTHROPIC_BASE_URL")
+    if anthropic_api_base:
+        logger.info(f"Configured Anthropic client with base URL: {anthropic_api_base}")
+
+
 class KAgentApp:
     def __init__(
         self,
@@ -86,6 +99,8 @@ def __init__(
         self.agent_config = agent_config
 
     def build(self, local=False) -> FastAPI:
+        _configure_anthropic_client()
+
         session_service = InMemorySessionService()
         token_service = None
         http_client: Optional[httpx.AsyncClient] = None
diff --git a/python/packages/kagent-adk/src/kagent/adk/models/_anthropic.py b/python/packages/kagent-adk/src/kagent/adk/models/_anthropic.py
index b8e9e68cd..b1313fd8d 100644
--- a/python/packages/kagent-adk/src/kagent/adk/models/_anthropic.py
+++ b/python/packages/kagent-adk/src/kagent/adk/models/_anthropic.py
@@ -44,11 +44,12 @@ def _create_http_client(self):
     @cached_property
     def _anthropic_client(self) -> AsyncAnthropic:
         api_key = self._api_key or os.environ.get("ANTHROPIC_API_KEY")
+        base_url = self.base_url or os.environ.get("ANTHROPIC_BASE_URL")
         kwargs = {}
         if api_key:
             kwargs["api_key"] = api_key
-        if self.base_url:
-            kwargs["base_url"] = self.base_url
+        if base_url:
+            kwargs["base_url"] = base_url
         if self.extra_headers:
             kwargs["default_headers"] = self.extra_headers
 
diff --git a/python/packages/kagent-adk/tests/unittests/models/test_anthropic.py b/python/packages/kagent-adk/tests/unittests/models/test_anthropic.py
index c69739c12..1e7f8f5d9 100644
--- a/python/packages/kagent-adk/tests/unittests/models/test_anthropic.py
+++ b/python/packages/kagent-adk/tests/unittests/models/test_anthropic.py
@@ -35,6 +35,23 @@ def test_client_uses_base_url(self):
             _ = llm._anthropic_client
             assert mock_anthropic.call_args.kwargs["base_url"] == "https://proxy.internal/anthropic"
 
+    def test_client_falls_back_to_env_base_url(self):
+        llm = KAgentAnthropicLlm(model="claude-3-sonnet-20240229")
+        with mock.patch.dict("os.environ", {"ANTHROPIC_BASE_URL": "https://env-proxy.internal/anthropic"}):
+            with mock.patch("kagent.adk.models._anthropic.AsyncAnthropic") as mock_anthropic:
+                mock_anthropic.return_value = mock.MagicMock(spec=AsyncAnthropic)
+                _ = llm._anthropic_client
+                assert mock_anthropic.call_args.kwargs["base_url"] == "https://env-proxy.internal/anthropic"
+
+    def test_explicit_base_url_takes_precedence_over_env(self):
+        llm = KAgentAnthropicLlm(model="claude-3-sonnet-20240229", base_url="https://explicit.internal/anthropic")
+        with mock.patch.dict("os.environ", {"ANTHROPIC_BASE_URL": "https://env.internal/anthropic"}):
+            with mock.patch("kagent.adk.models._anthropic.AsyncAnthropic") as mock_anthropic:
+                mock_anthropic.return_value = mock.MagicMock(spec=AsyncAnthropic)
+                _ = llm._anthropic_client
+                # Explicit base_url wins over env
+                assert mock_anthropic.call_args.kwargs["base_url"] == "https://explicit.internal/anthropic"
+
     def test_client_uses_extra_headers(self):
         llm = KAgentAnthropicLlm(model="claude-3-sonnet-20240229", extra_headers={"X-Org": "test-org"})
         with mock.patch("kagent.adk.models._anthropic.AsyncAnthropic") as mock_anthropic: