Fix: BYOM Claude detection in LiteLLM client via shared name helper

BYOM discovery does not expose modelFamily, so the LiteLLM client's
is_claude checks silently fell through for custom-named Claude
deployments. Extract the keyword heuristic into a shared
is_anthropic_model_name() helper in core and use it as a fallback
whenever modelFamily is None. Refactor the two langchain call sites
to consume the same helper.

Core 1.9.0 -> 1.9.1. Langchain now requires core >= 1.9.1.

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

Author: cosminacho

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 All notable changes to `uipath_llm_client` (core package) will be documented in this file.
 
+## [1.9.1] - 2026-04-17
+
+### Added
+- `is_anthropic_model_name()` helper and `ANTHROPIC_MODEL_NAME_KEYWORDS` tuple in `settings.constants` — name-based Claude detection for BYOM deployments where discovery does not expose `modelFamily`
+
+### Fixed
+- `UiPathLiteLLM` now detects Claude-family models by name when `modelFamily` is unavailable (BYOM), correctly routing Bedrock/Vertex provider selection and default flavors
+
 ## [1.9.0] - 2026-04-17
 
 ### Added

packages/uipath_langchain_client/CHANGELOG.md

@@ -5,7 +5,10 @@ All notable changes to `uipath_langchain_client` will be documented in this file
 ## [1.9.1] - 2026-04-17
 
 ### Fixed
-- Detect Anthropic-family models by additional name keywords (`anthropic`, `opus`, `sonnet`, `haiku`, `mythos`) alongside `claude` — applies to Bedrock INVOKE factory routing and the normalized client's empty tool-call content workaround
+- Detect Anthropic-family models by additional name keywords (`anthropic`, `opus`, `sonnet`, `haiku`, `mythos`) alongside `claude` — applies to Bedrock INVOKE factory routing and the normalized client's empty tool-call content workaround. Uses the shared `is_anthropic_model_name()` helper from core 1.9.1.
+
+### Changed
+- Minimum `uipath-llm-client` bumped to 1.9.1 for the shared `is_anthropic_model_name()` helper
 
 ## [1.9.0] - 2026-04-17
 

packages/uipath_langchain_client/pyproject.toml

@@ -6,7 +6,7 @@ readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "langchain>=1.2.15",
-    "uipath-llm-client>=1.9.0",
+    "uipath-llm-client>=1.9.1",
 ]
 
 [project.optional-dependencies]

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

@@ -65,7 +65,12 @@
 from pydantic import AliasChoices, BaseModel, Field
 
 from uipath_langchain_client.base_client import UiPathBaseChatModel
-from uipath_langchain_client.settings import ApiType, RoutingMode, UiPathAPIConfig
+from uipath_langchain_client.settings import (
+    ApiType,
+    RoutingMode,
+    UiPathAPIConfig,
+    is_anthropic_model_name,
+)
 
 _DictOrPydanticClass = Union[dict[str, Any], type[BaseModel], type]
 _DictOrPydantic = Union[dict[str, Any], BaseModel]
@@ -412,10 +417,7 @@ def _preprocess_request(
                         converted_message["content"] = ""
                 if (
                     self.model_name
-                    and any(
-                        kw in self.model_name.lower()
-                        for kw in ("anthropic", "claude", "opus", "sonnet", "haiku", "mythos")
-                    )
+                    and is_anthropic_model_name(self.model_name)
                     and not converted_message["content"]
                 ):
                     converted_message["content"] = "tool_call"

packages/uipath_langchain_client/src/uipath_langchain_client/factory.py

@@ -35,6 +35,7 @@
     UiPathBaseSettings,
     VendorType,
     get_default_client_settings,
+    is_anthropic_model_name,
 )
 
 
@@ -174,13 +175,7 @@ def get_chat_model(
         case VendorType.AWSBEDROCK:
             if (
                 model_family == ModelFamily.ANTHROPIC_CLAUDE and api_flavor != ApiFlavor.CONVERSE
-            ) or (
-                api_flavor == ApiFlavor.INVOKE
-                and any(
-                    kw in model_name.lower()
-                    for kw in ("anthropic", "claude", "opus", "sonnet", "haiku", "mythos")
-                )
-            ):
+            ) or (api_flavor == ApiFlavor.INVOKE and is_anthropic_model_name(model_name)):
                 from uipath_langchain_client.clients.bedrock.chat_models import (
                     UiPathChatAnthropicBedrock,
                 )

packages/uipath_langchain_client/src/uipath_langchain_client/settings.py

@@ -31,6 +31,7 @@
     ModelFamily,
     RoutingMode,
     VendorType,
+    is_anthropic_model_name,
 )
 
 __all__ = [
@@ -47,4 +48,5 @@
     "VendorType",
     "API_FLAVOR_TO_VENDOR_TYPE",
     "BYOM_TO_ROUTING_FLAVOR",
+    "is_anthropic_model_name",
 ]

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__ = "1.9.0"
+__version__ = "1.9.1"

src/uipath/llm_client/clients/litellm/client.py

@@ -34,6 +34,7 @@
     ModelFamily,
     RoutingMode,
     VendorType,
+    is_anthropic_model_name,
 )
 from uipath.llm_client.utils.retry import RetryConfig
 
@@ -191,7 +192,6 @@ def _discover_and_build_api_config(
         model_info = self._client_settings.get_model_info(self._model_name, vendor_type=vendor_type)
 
         model_family = model_info.get("modelFamily", None)
-
         discovered_vendor = model_info.get("vendor", None)
         discovered_flavor = model_info.get("apiFlavor", None)
 
@@ -217,20 +217,18 @@ def _discover_and_build_api_config(
         if resolved_flavor is None and resolved_vendor in ("openai", "azure"):
             resolved_flavor = ApiFlavor.CHAT_COMPLETIONS
 
+        # Claude detection: modelFamily from discovery, or name heuristic for BYOM
+        # (BYOM discovery does not expose modelFamily).
+        is_claude = model_family == ModelFamily.ANTHROPIC_CLAUDE or (
+            model_family is None and is_anthropic_model_name(self._model_name)
+        )
+
         # Claude on Bedrock defaults to invoke
-        if (
-            resolved_flavor is None
-            and resolved_vendor == "awsbedrock"
-            and model_family == ModelFamily.ANTHROPIC_CLAUDE
-        ):
+        if resolved_flavor is None and resolved_vendor == "awsbedrock" and is_claude:
             resolved_flavor = ApiFlavor.INVOKE
 
         # Claude on Vertex defaults to anthropic-claude
-        if (
-            resolved_flavor is None
-            and resolved_vendor == "vertexai"
-            and model_family == ModelFamily.ANTHROPIC_CLAUDE
-        ):
+        if resolved_flavor is None and resolved_vendor == "vertexai" and is_claude:
             resolved_flavor = ApiFlavor.ANTHROPIC_CLAUDE
 
         api_config = UiPathAPIConfig(
@@ -247,7 +245,9 @@ def _resolve_llm_provider(self) -> str:
         The model_family disambiguates cases where the same vendor hosts
         models from different providers (e.g. Claude on Vertex AI or Bedrock).
         """
-        is_claude = self._model_family == ModelFamily.ANTHROPIC_CLAUDE
+        is_claude = self._model_family == ModelFamily.ANTHROPIC_CLAUDE or (
+            self._model_family is None and is_anthropic_model_name(self._model_name)
+        )
         vendor = str(self._api_config.vendor_type or "openai")
 
         # Claude on Vertex AI → vertex_ai (uses VertexAIAnthropicConfig)

src/uipath/llm_client/settings/constants.py

@@ -70,3 +70,19 @@ class ByomApiFlavor(StrEnum):
     ByomApiFlavor.AWS_BEDROCK_INVOKE: ApiFlavor.INVOKE,
     ByomApiFlavor.AWS_BEDROCK_CONVERSE: ApiFlavor.CONVERSE,
 }
+
+
+ANTHROPIC_MODEL_NAME_KEYWORDS: tuple[str, ...] = (
+    "anthropic",
+    "claude",
+    "opus",
+    "sonnet",
+    "haiku",
+    "mythos",
+)
+
+
+def is_anthropic_model_name(model_name: str) -> bool:
+    """Heuristic fallback for when discovery's ``modelFamily`` is unavailable (e.g. BYOM)."""
+    lower = model_name.lower()
+    return any(kw in lower for kw in ANTHROPIC_MODEL_NAME_KEYWORDS)