Feat: strip unsupported sampling params for claude-opus-4+ across all Anthropic clients

Move detection logic and constant to core (model_family.py) so a single
definition covers all LangChain clients.

  - is_claude_opus_4_or_above()           — core model_family.py
  - CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS  — core model_family.py
  - Re-exported from uipath_langchain_client.utils

Per-client strip strategy:
  - UiPathChatAnthropic          → _get_request_payload override
  - UiPathChatAnthropicBedrock   → _get_request_payload override (import from core)
  - UiPathChatBedrockConverse     → _converse_params override (strips temperature/topP
                                    from inferenceConfig)
  - UiPathChatBedrock (INVOKE)   → model_validator (nulls self.temperature,
                                    filters model_kwargs)
  - UiPathChat (normalized)      → _default_params (strips + existing thinking check)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: cosminacho

CHANGELOG.md

@@ -4,8 +4,8 @@ All notable changes to `uipath_llm_client` (core package) will be documented in
 
 ## [1.9.9] - 2026-04-23
 
-### Changed
-- Bumped dependency floors to the latest installed versions: `uipath-platform>=0.1.35`.
+### Added
+- `is_claude_opus_4_or_above(model_name)` and `CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS` added to `uipath.llm_client.utils.model_family` — identifies Claude Opus 4+ reasoning models and the sampling parameters (`temperature`, `top_k`, `top_p`) that the Anthropic API rejects for them.
 
 ## [1.9.8] - 2026-04-22
 

packages/uipath_langchain_client/CHANGELOG.md

@@ -2,16 +2,12 @@
 
 All notable changes to `uipath_langchain_client` will be documented in this file.
 
-## [1.9.10] - 2026-04-23
-
-### Fixed
-- `UiPathChatAnthropicBedrock` now strips `temperature`, `top_k`, and `top_p` from the request payload when the model name matches `claude-opus-4` (e.g. `anthropic.claude-opus-4-7`). These sampling parameters are not supported by Claude Opus 4+ reasoning models and previously caused a `400 Bad Request` from the gateway. Requests for other models (e.g. claude-haiku) are unaffected.
-
 ## [1.9.9] - 2026-04-23
 
-### Changed
-- Bumped dependency floors to the latest installed versions: `langchain-openai>=1.2.0`, `langchain-aws>=1.4.5`.
-- Minimum `uipath-llm-client` bumped to 1.9.9 to match the core dependency-floor release.
+### Fixed
+- Claude Opus 4+ reasoning models (e.g. `anthropic.claude-opus-4-7`) reject `temperature`, `top_k`, and `top_p` with `400 Bad Request`. All five UiPath Anthropic clients now strip those params automatically: `UiPathChatAnthropic` and `UiPathChatAnthropicBedrock` via `_get_request_payload`; `UiPathChatBedrockConverse` via `_converse_params` (strips `temperature`/`topP` from `inferenceConfig`); `UiPathChatBedrock` (INVOKE) via model validator; `UiPathChat` (normalized) via `_default_params`. Requests for other models are unaffected.
+- `UiPathChat._default_params` drops `temperature` when `thinking` is also set. Anthropic's extended thinking API requires `temperature=1` (its default) and rejects any other explicit value.
+- Detection logic (`is_claude_opus_4_or_above`) and the unsupported-param constant (`CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS`) are defined in core `uipath.llm_client.utils.model_family` and re-exported from `uipath_langchain_client.utils`.
 
 ## [1.9.8] - 2026-04-22
 
@@ -442,3 +438,4 @@ All notable changes to `uipath_langchain_client` will be documented in this file
 - Tool/function calling support
 - Full compatibility with LangChain's `BaseChatModel` interface
 - httpx-based HTTP handling for consistent behavior
+

packages/uipath_langchain_client/pyproject.toml

@@ -6,7 +6,7 @@ readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "langchain>=1.2.15,<2.0.0",
-    "uipath-llm-client>=1.9.9,<2.0.0",
+    "uipath-llm-client>=1.9.10,<2.0.0",
 ]
 
 [project.optional-dependencies]

packages/uipath_langchain_client/src/uipath_langchain_client/clients/anthropic/chat_models.py

@@ -1,6 +1,7 @@
 from functools import cached_property
 from typing import Any, Self
 
+from langchain_core.language_models import LanguageModelInput
 from pydantic import Field, model_validator
 from typing_extensions import override
 
@@ -12,6 +13,10 @@
     UiPathAPIConfig,
     VendorType,
 )
+from uipath_langchain_client.utils import (
+    CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS,
+    is_claude_opus_4_or_above,
+)
 
 try:
     from anthropic import (
@@ -151,6 +156,20 @@ def _async_anthropic_client(
             case _:
                 raise ValueError("Anthropic models are currently not hosted on any other provider")
 
+    @override
+    def _get_request_payload(
+        self,
+        input_: LanguageModelInput,
+        *,
+        stop: list[str] | None = None,
+        **kwargs: Any,
+    ) -> dict:
+        payload = super()._get_request_payload(input_, stop=stop, **kwargs)
+        if is_claude_opus_4_or_above(self.model):
+            for param in CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS:
+                payload.pop(param, None)
+        return payload
+
     @override
     def _create(self, payload: dict[str, Any]) -> Any:
         if "betas" in payload:

packages/uipath_langchain_client/src/uipath_langchain_client/clients/bedrock/chat_models.py

@@ -1,4 +1,3 @@
-import re
 from functools import cached_property
 from typing import Any, Self
 
@@ -14,6 +13,10 @@
     UiPathAPIConfig,
     VendorType,
 )
+from uipath_langchain_client.utils import (
+    CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS,
+    is_claude_opus_4_or_above,
+)
 
 try:
     from anthropic import AnthropicBedrock, AsyncAnthropicBedrock
@@ -51,16 +54,6 @@ def _patched_format_data_content_block(block: dict) -> dict:
     ) from e
 
 
-# Sampling parameters that Claude Opus 4+ (reasoning models) do not support.
-# The API returns 400 if any of these are present in the request payload.
-_CLAUDE_OPUS_4_UNSUPPORTED_PARAMS: frozenset[str] = frozenset({"temperature", "top_k", "top_p"})
-
-
-def _is_claude_opus_4_or_above(model_name: str) -> bool:
-    """Return True for Claude Opus 4+ models that reject sampling parameters."""
-    return bool(re.search(r"claude-opus-4", model_name, re.IGNORECASE))
-
-
 class UiPathChatBedrockConverse(UiPathBaseChatModel, ChatBedrockConverse):  # type: ignore[override]
     api_config: UiPathAPIConfig = UiPathAPIConfig(
         api_type=ApiType.COMPLETIONS,
@@ -89,6 +82,16 @@ def setup_uipath_client(self) -> Self:
         self.client = WrappedBotoClient(self.uipath_sync_client)
         return self
 
+    @override
+    def _converse_params(self, **kwargs: Any) -> dict:
+        params = super()._converse_params(**kwargs)
+        if is_claude_opus_4_or_above(self.model_id):
+            inference = params.get("inferenceConfig")
+            if isinstance(inference, dict):
+                inference.pop("temperature", None)
+                inference.pop("topP", None)
+        return params
+
 
 class UiPathChatBedrock(UiPathBaseChatModel, ChatBedrock):  # type: ignore[override]
     api_config: UiPathAPIConfig = UiPathAPIConfig(
@@ -116,6 +119,14 @@ def setup_model_id(cls, values: Any) -> Any:
     @model_validator(mode="after")
     def setup_uipath_client(self) -> Self:
         self.client = WrappedBotoClient(self.uipath_sync_client)
+        if is_claude_opus_4_or_above(self.model_id):
+            self.temperature = None
+            if self.model_kwargs:
+                self.model_kwargs = {
+                    k: v
+                    for k, v in self.model_kwargs.items()
+                    if k not in CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS
+                }
         return self
 
     @property
@@ -170,7 +181,7 @@ def _get_request_payload(
         **kwargs: Any,
     ) -> dict:
         payload = super()._get_request_payload(input_, stop=stop, **kwargs)
-        if _is_claude_opus_4_or_above(self.model):
-            for param in _CLAUDE_OPUS_4_UNSUPPORTED_PARAMS:
+        if is_claude_opus_4_or_above(self.model):
+            for param in CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS:
                 payload.pop(param, None)
         return payload

packages/uipath_langchain_client/src/uipath_langchain_client/clients/normalized/chat_models.py

@@ -66,7 +66,11 @@
 
 from uipath_langchain_client.base_client import UiPathBaseChatModel
 from uipath_langchain_client.settings import ApiType, RoutingMode, UiPathAPIConfig
-from uipath_langchain_client.utils import is_anthropic_model_name
+from uipath_langchain_client.utils import (
+    CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS,
+    is_anthropic_model_name,
+    is_claude_opus_4_or_above,
+)
 
 _DictOrPydanticClass = Union[dict[str, Any], type[BaseModel], type]
 _DictOrPydantic = Union[dict[str, Any], BaseModel]
@@ -251,6 +255,11 @@ def _default_params(self) -> dict[str, Any]:
         if "thinking" in params:
             params.pop("temperature", None)
 
+        # Claude Opus 4+ reasoning models reject temperature, top_k and top_p entirely.
+        if is_claude_opus_4_or_above(self.model_name):
+            for param in CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS:
+                params.pop(param, None)
+
         return {**params, **self.model_kwargs}
 
     def _get_usage_metadata(self, json_data: dict[str, Any]) -> UsageMetadata:

packages/uipath_langchain_client/src/uipath_langchain_client/utils.py

@@ -15,7 +15,9 @@
 )
 from uipath.llm_client.utils.model_family import (
     ANTHROPIC_MODEL_NAME_KEYWORDS,
+    CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS,
     is_anthropic_model_name,
+    is_claude_opus_4_or_above,
 )
 from uipath.llm_client.utils.retry import RetryConfig
 
@@ -36,4 +38,6 @@
     "UiPathTooManyRequestsError",
     "ANTHROPIC_MODEL_NAME_KEYWORDS",
     "is_anthropic_model_name",
+    "CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS",
+    "is_claude_opus_4_or_above",
 ]

src/uipath/llm_client/__version__.py

@@ -1,3 +1,3 @@
 __title__ = "UiPath LLM Client"
 __description__ = "A Python client for interacting with UiPath's LLM services."
-__version__ = "1.9.9"
+__version__ = "1.9.10"

src/uipath/llm_client/utils/model_family.py

@@ -4,6 +4,8 @@
 deployments do not expose it. These helpers provide a name-based fallback.
 """
 
+import re
+
 ANTHROPIC_MODEL_NAME_KEYWORDS: tuple[str, ...] = (
     "anthropic",
     "claude",
@@ -13,8 +15,23 @@
     "mythos",
 )
 
+# Sampling parameters that Claude Opus 4+ (and similar reasoning models) do not support.
+# The Anthropic API returns 400 Bad Request if any of these appear in the request payload.
+CLAUDE_OPUS_4_UNSUPPORTED_SAMPLING_PARAMS: frozenset[str] = frozenset(
+    {"temperature", "top_k", "top_p"}
+)
+
 
 def is_anthropic_model_name(model_name: str) -> bool:
     """Return True if ``model_name`` looks like an Anthropic Claude-family model."""
     lower = model_name.lower()
     return any(kw in lower for kw in ANTHROPIC_MODEL_NAME_KEYWORDS)
+
+
+def is_claude_opus_4_or_above(model_name: str) -> bool:
+    """Return True for Claude Opus 4+ reasoning models that reject sampling parameters.
+
+    These models do not accept ``temperature``, ``top_k``, or ``top_p``; sending
+    any of them causes a ``400 Bad Request`` from the Anthropic API.
+    """
+    return bool(re.search(r"claude-opus-4", model_name, re.IGNORECASE))