fix: use availableOperationCodes for BYOM validation, bump to 1.5.9

- Core: use availableOperationCodes field in LLMGateway BYOM validation
- LangChain: remove fix_host_header event hooks from UiPathChatOpenAI
- Bump both packages to 1.5.9

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: cosminacho

CHANGELOG.md

@@ -2,10 +2,15 @@
 
 All notable changes to `uipath_llm_client` (core package) will be documented in this file.
 
+## [1.5.9] - 2026-03-26
+
+### Fix
+- Use `availableOperationCodes` field (instead of `operationCodes`) when validating BYOM operation codes
+
 ## [1.5.8] - 2026-03-26
 
 ### Fix
-- Set correct host for BYOM requests which resulted in 403 from cloudflare
+- Pass `base_url` to `OpenAI` and `AsyncOpenAI` constructors in `UiPathOpenAI` and `UiPathAsyncOpenAI` to ensure the correct endpoint is forwarded to the underlying SDK clients
 
 ## [1.5.7] - 2026-03-23
 

packages/uipath_langchain_client/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 All notable changes to `uipath_langchain_client` will be documented in this file.
 
+## [1.5.9] - 2026-03-26
+
+### Fix
+- Remove `fix_host_header` event hooks from `UiPathChatOpenAI`; host header management is handled by the underlying httpx client
+
 ## [1.5.8] - 2026-03-26
 
 ### Fix

packages/uipath_langchain_client/pyproject.toml

@@ -6,7 +6,7 @@ readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "langchain>=1.2.13",
-    "uipath-llm-client>=1.5.8",
+    "uipath-llm-client>=1.5.9",
 ]
 
 [project.optional-dependencies]

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__ = "1.5.8"
+__version__ = "1.5.9"

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

@@ -60,17 +60,6 @@ async def fix_url_and_api_flavor_header_async(request: Request):
         self.uipath_sync_client.event_hooks["request"].append(fix_url_and_api_flavor_header)
         self.uipath_async_client.event_hooks["request"].append(fix_url_and_api_flavor_header_async)
 
-        correct_host = URL(base_url).host
-
-        def fix_host_header(request: Request) -> None:
-            request.headers["host"] = correct_host
-
-        async def fix_host_header_async(request: Request) -> None:
-            request.headers["host"] = correct_host
-
-        self.uipath_sync_client.event_hooks["request"].append(fix_host_header)
-        self.uipath_async_client.event_hooks["request"].append(fix_host_header_async)
-
         self.root_client = OpenAI(
             api_key="PLACEHOLDER",
             max_retries=0,  # handled by the UiPath client

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__ = "1.5.8"
+__version__ = "1.5.9"