Fix: drop temperature from UiPathChat payload when thinking is set

Anthropic's extended thinking API requires temperature=1 (its default)
and rejects any other explicit value alongside a thinking config.
_default_params now silently removes temperature when thinking is
present so callers don't have to manually avoid the combination.

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

Author: cosminacho

packages/uipath_langchain_client/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 All notable changes to `uipath_langchain_client` will be documented in this file.
 
+## [1.9.9] - 2026-04-23
+
+### Fixed
+- `UiPathChat._default_params` now drops `temperature` when `thinking` is also set. Anthropic's extended thinking API requires `temperature=1` (its default) and rejects any other explicit value, so forwarding a caller-supplied temperature alongside a `thinking` config would cause a gateway validation error.
+
 ## [1.9.8] - 2026-04-22
 
 ### Changed

packages/uipath_langchain_client/src/uipath_langchain_client/__version__.py

@@ -1,3 +1,3 @@
 __title__ = "UiPath LangChain Client"
 __description__ = "A Python client for interacting with UiPath's LLM services via LangChain."
-__version__ = "1.9.8"
+__version__ = "1.9.9"

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

@@ -243,10 +243,15 @@ def _default_params(self) -> dict[str, Any]:
         }
 
         set_fields = self.model_fields_set
-        return {
-            **{k: v for k, v in candidates.items() if k in set_fields},
-            **self.model_kwargs,
-        }
+        params = {k: v for k, v in candidates.items() if k in set_fields}
+
+        # Anthropic extended thinking requires temperature=1 (the API default).
+        # Sending any explicit temperature alongside thinking causes a validation error,
+        # so we drop it here and let the gateway apply the correct default.
+        if "thinking" in params:
+            params.pop("temperature", None)
+
+        return {**params, **self.model_kwargs}
 
     def _get_usage_metadata(self, json_data: dict[str, Any]) -> UsageMetadata:
         return UsageMetadata(