fix(anthropic): support effort="max" and remove beta headers (#35141)

Author: ccurme

libs/partners/anthropic/langchain_anthropic/chat_models.py

@@ -872,7 +872,7 @@ class ChatAnthropic(BaseChatModel):
     `#!python {"type": "adaptive"}`
     """
 
-    effort: Literal["high", "medium", "low"] | None = None
+    effort: Literal["max", "high", "medium", "low"] | None = None
     """Control how many tokens Claude uses when responding.
 
     This parameter will be merged into the `output_config` parameter when making
@@ -887,13 +887,8 @@ class ChatAnthropic(BaseChatModel):
 
     !!! note "Model Support"
 
-        This feature is currently only supported by Claude Opus 4.5.
-
-    !!! note "Automatic beta header"
-
-        The required `effort-2025-11-24` beta header is
-        automatically appended to the request when using `effort`, so you
-        don't need to manually specify it in the `betas` parameter.
+        This feature is generally available on Claude Opus 4.6 and Claude Opus 4.5.
+        The `max` effort level is only supported by Claude Opus 4.6.
     """
 
     mcp_servers: list[dict[str, Any]] | None = None
@@ -1164,16 +1159,6 @@ def _get_request_payload(
         if output_config:
             payload["output_config"] = output_config
 
-            # Auto-append required beta for effort
-            if "effort" in output_config:
-                required_beta = "effort-2025-11-24"
-                if payload["betas"]:
-                    # Merge with existing betas
-                    if required_beta not in payload["betas"]:
-                        payload["betas"] = [*payload["betas"], required_beta]
-                else:
-                    payload["betas"] = [required_beta]
-
         if "response_format" in payload:
             # response_format present when using agents.create_agent's ProviderStrategy
             # ---

libs/partners/anthropic/tests/unit_tests/test_chat_models.py

@@ -2085,7 +2085,7 @@ async def test_model_profile_not_blocking() -> None:
 def test_effort_parameter_validation() -> None:
     """Test that effort parameter is validated correctly.
 
-    The effort parameter is currently in beta and only supported by Claude Opus 4.5.
+    The effort parameter is generally available on Claude Opus 4.6 and Opus 4.5.
     """
     # Valid effort values should work
     model = ChatAnthropic(model="claude-opus-4-5-20251101", effort="high")
@@ -2097,20 +2097,22 @@ def test_effort_parameter_validation() -> None:
     model = ChatAnthropic(model="claude-opus-4-5-20251101", effort="low")
     assert model.effort == "low"
 
+    model = ChatAnthropic(model="claude-opus-4-6", effort="max")
+    assert model.effort == "max"
+
     # Invalid effort values should raise ValidationError
     with pytest.raises(ValidationError, match="Input should be"):
         ChatAnthropic(model="claude-opus-4-5-20251101", effort="invalid")  # type: ignore[arg-type]
 
 
-def test_effort_populates_betas() -> None:
-    """Test that effort parameter auto-populates required betas."""
+def test_effort_in_output_config_payload() -> None:
+    """Test that effort parameter is properly added to output_config in payload."""
     model = ChatAnthropic(model="claude-opus-4-5-20251101", effort="medium")
     assert model.effort == "medium"
 
-    # Test that effort works with dated API ID
+    # Test that effort is added to output_config
     payload = model._get_request_payload("Test query")
     assert payload["output_config"]["effort"] == "medium"
-    assert "effort-2025-11-24" in payload["betas"]
 
 
 def test_effort_in_output_config() -> None:
@@ -2136,43 +2138,6 @@ def test_effort_priority() -> None:
     assert payload["output_config"]["effort"] == "high"
 
 
-def test_effort_beta_header_auto_append() -> None:
-    """Test that effort beta header is automatically appended."""
-    # Test with top-level effort parameter
-    model = ChatAnthropic(model="claude-opus-4-5-20251101", effort="medium")
-    payload = model._get_request_payload("Test query")
-    assert "effort-2025-11-24" in payload["betas"]
-
-    # Test with output_config
-    model = ChatAnthropic(
-        model="claude-opus-4-5-20251101",
-        output_config={"effort": "low"},
-    )
-    payload = model._get_request_payload("Test query")
-    assert "effort-2025-11-24" in payload["betas"]
-
-    # Test that beta is not duplicated if already present
-    model = ChatAnthropic(
-        model="claude-opus-4-5-20251101",
-        effort="high",
-        betas=["effort-2025-11-24"],
-    )
-    payload = model._get_request_payload("Test query")
-    assert payload["betas"].count("effort-2025-11-24") == 1
-
-    # Test combining effort with other betas
-    model = ChatAnthropic(
-        model="claude-opus-4-5-20251101",
-        effort="medium",
-        betas=["context-1m-2025-08-07"],
-    )
-    payload = model._get_request_payload("Test query")
-    assert set(payload["betas"]) == {
-        "context-1m-2025-08-07",
-        "effort-2025-11-24",
-    }
-
-
 def test_output_config_without_effort() -> None:
     """Test that output_config can be used without effort."""
     # output_config might have other fields in the future
@@ -2182,10 +2147,6 @@ def test_output_config_without_effort() -> None:
     )
     payload = model._get_request_payload("Test query")
     assert payload["output_config"] == {"some_future_param": "value"}
-    # No effort beta should be added
-    assert payload.get("betas") is None or "effort-2025-11-24" not in payload.get(
-        "betas", []
-    )
 
 
 def test_extras_with_defer_loading() -> None: