feat: per-vendor model_name defaults on new chat clients

Ports the legacy model_name defaults from the pre-migration
UiPathRequestMixin / BedrockModels / GeminiModels over to the new
uipath_langchain_client-backed re-exports so callers can construct
UiPathChat(), UiPathChatBedrock(), UiPathChatVertex() etc. with no args.

Defaults per vendor:
- OpenAI / Azure (UiPathChat, UiPathAzureChatOpenAI, UiPathChatOpenAI):
  UIPATH_MODEL_NAME env var, fallback gpt-4.1-mini-2025-04-14.
- Bedrock (UiPathChatBedrock, UiPathChatAnthropicBedrock,
  UiPathChatBedrockConverse): anthropic.claude-haiku-4-5-20251001-v1:0.
- Vertex (UiPathChatGoogleGenerativeAI, UiPathChatVertex): gemini-2.5-flash.

Classes without a legacy equivalent (UiPathChatAnthropic,
UiPathChatAnthropicVertex, UiPathChatFireworks) keep model= required.

Implementation: defaults are attached inline in the per-vendor re-export
files (chat/openai.py, chat/bedrock.py, chat/vertex.py, chat/models.py).
For most classes this is a one-liner FieldInfo mutation
(cls.model_fields["model_name"].default_factory = factory;
cls.model_rebuild(force=True)) which pydantic V2 scopes per class.

UiPathChatBedrockConverse is the one class where the field-default path
does not suffice — its upstream ChatBedrockConverse.set_disable_streaming
before-validator reads model / model_id from the raw input dict before
field defaults fire — so it gets a thin subclass with our own
@model_validator(mode="before") that injects the default into values.

Version bump 0.10.5 -> 0.10.6.

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

Author: cosminacho

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "uipath-langchain"
-version = "0.10.5"
+version = "0.10.6"
 description = "Python SDK that enables developers to build and deploy LangGraph agents to the UiPath Cloud Platform"
 readme = { file = "README.md", content-type = "text/markdown" }
 requires-python = ">=3.11"

src/uipath_langchain/chat/__init__.py

@@ -24,45 +24,35 @@ def __getattr__(name):
 
         return get_chat_model
     if name == "UiPathChat":
-        from uipath_langchain_client.clients.normalized.chat_models import (
-            UiPathChat,
-        )
+        from .openai import UiPathChat
 
         return UiPathChat
     if name == "UiPathAzureChatOpenAI":
-        from uipath_langchain_client.clients.openai.chat_models import (
-            UiPathAzureChatOpenAI,
-        )
+        from .openai import UiPathAzureChatOpenAI
 
         return UiPathAzureChatOpenAI
     if name == "UiPathChatOpenAI":
-        from uipath_langchain_client.clients.openai.chat_models import (
-            UiPathChatOpenAI,
-        )
+        from .openai import UiPathChatOpenAI
 
         return UiPathChatOpenAI
     if name == "UiPathChatGoogleGenerativeAI":
-        from uipath_langchain_client.clients.google.chat_models import (
-            UiPathChatGoogleGenerativeAI,
-        )
+        from .vertex import UiPathChatGoogleGenerativeAI
 
         return UiPathChatGoogleGenerativeAI
+    if name == "UiPathChatVertex":
+        from .vertex import UiPathChatVertex
+
+        return UiPathChatVertex
     if name == "UiPathChatBedrock":
-        from uipath_langchain_client.clients.bedrock.chat_models import (
-            UiPathChatBedrock,
-        )
+        from .bedrock import UiPathChatBedrock
 
         return UiPathChatBedrock
     if name == "UiPathChatBedrockConverse":
-        from uipath_langchain_client.clients.bedrock.chat_models import (
-            UiPathChatBedrockConverse,
-        )
+        from .bedrock import UiPathChatBedrockConverse
 
         return UiPathChatBedrockConverse
     if name == "UiPathChatAnthropicBedrock":
-        from uipath_langchain_client.clients.bedrock.chat_models import (
-            UiPathChatAnthropicBedrock,
-        )
+        from .bedrock import UiPathChatAnthropicBedrock
 
         return UiPathChatAnthropicBedrock
     if name == "UiPathChatAnthropic":
@@ -83,12 +73,6 @@ def __getattr__(name):
         )
 
         return UiPathChatFireworks
-    if name == "UiPathChatVertex":
-        from uipath_langchain_client.clients.google.chat_models import (
-            UiPathChatGoogleGenerativeAI,
-        )
-
-        return UiPathChatGoogleGenerativeAI
     if name in ("OpenAIModels", "BedrockModels", "GeminiModels"):
         from uipath_langchain.chat._legacy import supported_models
 

src/uipath_langchain/chat/bedrock.py

@@ -1,8 +1,36 @@
+from typing import Any
+
+from pydantic import model_validator
 from uipath_langchain_client.clients.bedrock.chat_models import (
     UiPathChatAnthropicBedrock,
     UiPathChatBedrock,
-    UiPathChatBedrockConverse,
 )
+from uipath_langchain_client.clients.bedrock.chat_models import (
+    UiPathChatBedrockConverse as _UpstreamUiPathChatBedrockConverse,
+)
+
+DEFAULT_MODEL_NAME = "anthropic.claude-haiku-4-5-20251001-v1:0"
+
+
+def _default_factory() -> str:
+    return DEFAULT_MODEL_NAME
+
+
+for _cls in (UiPathChatBedrock, UiPathChatAnthropicBedrock):
+    _cls.model_fields["model_name"].default_factory = _default_factory
+    _cls.model_rebuild(force=True)
+
+
+class UiPathChatBedrockConverse(_UpstreamUiPathChatBedrockConverse):
+    @model_validator(mode="before")
+    @classmethod
+    def _inject_default_model(cls, values: Any) -> Any:
+        if isinstance(values, dict) and not any(
+            k in values for k in ("model", "model_id", "model_name")
+        ):
+            values = {**values, "model": _default_factory()}
+        return values
+
 
 __all__ = [
     "UiPathChatBedrock",

src/uipath_langchain/chat/models.py

@@ -1,8 +1,4 @@
-from uipath_langchain_client.clients.normalized.chat_models import UiPathChat
-from uipath_langchain_client.clients.openai.chat_models import (
-    UiPathAzureChatOpenAI,
-    UiPathChatOpenAI,
-)
+from .openai import UiPathAzureChatOpenAI, UiPathChat, UiPathChatOpenAI
 
 __all__ = [
     "UiPathChat",

src/uipath_langchain/chat/openai.py

@@ -1,9 +1,25 @@
+import os
+
+from uipath_langchain_client.clients.normalized.chat_models import UiPathChat
 from uipath_langchain_client.clients.openai.chat_models import (
     UiPathAzureChatOpenAI,
     UiPathChatOpenAI,
 )
 
+DEFAULT_MODEL_NAME = "gpt-4.1-mini-2025-04-14"
+
+
+def _default_factory() -> str:
+    return os.getenv("UIPATH_MODEL_NAME", DEFAULT_MODEL_NAME)
+
+
+for _cls in (UiPathChat, UiPathAzureChatOpenAI, UiPathChatOpenAI):
+    _cls.model_fields["model_name"].default_factory = _default_factory
+    _cls.model_rebuild(force=True)
+
+
 __all__ = [
+    "UiPathChat",
     "UiPathAzureChatOpenAI",
     "UiPathChatOpenAI",
 ]

src/uipath_langchain/chat/vertex.py

@@ -2,8 +2,21 @@
     UiPathChatGoogleGenerativeAI,
 )
 
+DEFAULT_MODEL_NAME = "gemini-2.5-flash"
+
+
+def _default_factory() -> str:
+    return DEFAULT_MODEL_NAME
+
+
+UiPathChatGoogleGenerativeAI.model_fields[
+    "model_name"
+].default_factory = _default_factory
+UiPathChatGoogleGenerativeAI.model_rebuild(force=True)
+
 UiPathChatVertex = UiPathChatGoogleGenerativeAI
 
+
 __all__ = [
     "UiPathChatGoogleGenerativeAI",
     "UiPathChatVertex",

tests/chat/test_default_model_name.py

@@ -0,0 +1,126 @@
+import pytest
+from pydantic import ValidationError
+from uipath_langchain_client.clients.bedrock.chat_models import (
+    UiPathChatBedrockConverse as _UpstreamBedrockConverse,
+)
+from uipath_langchain_client.clients.normalized.chat_models import (
+    UiPathChat as _UpstreamUiPathChat,
+)
+
+from uipath_langchain.chat import (
+    UiPathAzureChatOpenAI,
+    UiPathChat,
+    UiPathChatAnthropic,
+    UiPathChatAnthropicBedrock,
+    UiPathChatAnthropicVertex,
+    UiPathChatBedrock,
+    UiPathChatBedrockConverse,
+    UiPathChatFireworks,
+    UiPathChatGoogleGenerativeAI,
+    UiPathChatOpenAI,
+    UiPathChatVertex,
+)
+
+_DEFAULT_OPENAI = "gpt-4.1-mini-2025-04-14"
+_DEFAULT_BEDROCK = "anthropic.claude-haiku-4-5-20251001-v1:0"
+_DEFAULT_VERTEX = "gemini-2.5-flash"
+
+_FAKE_JWT = (
+    "eyJhbGciOiAiSFMyNTYiLCAidHlwIjogIkpXVCJ9."
+    "eyJzdWIiOiAidGVzdCIsICJpc3MiOiAidGVzdCJ9."
+    "signature"
+)
+
+
+@pytest.fixture(autouse=True)
+def _platform_env(monkeypatch):
+    monkeypatch.setenv("UIPATH_ACCESS_TOKEN", _FAKE_JWT)
+    monkeypatch.setenv("UIPATH_URL", "https://example.com/org/tenant/orchestrator_/")
+    monkeypatch.setenv("UIPATH_TENANT_ID", "tenant")
+    monkeypatch.setenv("UIPATH_ORGANIZATION_ID", "org")
+    monkeypatch.delenv("UIPATH_MODEL_NAME", raising=False)
+
+
+_CASES = [
+    (UiPathChat, _DEFAULT_OPENAI),
+    (UiPathAzureChatOpenAI, _DEFAULT_OPENAI),
+    (UiPathChatOpenAI, _DEFAULT_OPENAI),
+    (UiPathChatGoogleGenerativeAI, _DEFAULT_VERTEX),
+    (UiPathChatVertex, _DEFAULT_VERTEX),
+    (UiPathChatBedrock, _DEFAULT_BEDROCK),
+    (UiPathChatBedrockConverse, _DEFAULT_BEDROCK),
+    (UiPathChatAnthropicBedrock, _DEFAULT_BEDROCK),
+]
+
+
+@pytest.mark.parametrize("cls, expected", _CASES)
+class TestInstantiationWithoutModelKwarg:
+    def test_no_args_uses_default(self, cls, expected):
+        llm = cls()
+        assert llm.model_name == expected
+
+    def test_explicit_model_kwarg_overrides_default(self, cls, expected):
+        llm = cls(model="custom-model-id")
+        assert llm.model_name == "custom-model-id"
+
+
+def test_uipath_chat_no_args():
+    llm = UiPathChat()
+    assert llm.model_name == _DEFAULT_OPENAI
+
+
+def test_uipath_chat_bedrock_no_args():
+    llm = UiPathChatBedrock()
+    assert llm.model_name == _DEFAULT_BEDROCK
+
+
+def test_uipath_chat_bedrock_converse_no_args():
+    llm = UiPathChatBedrockConverse()
+    assert llm.model_name == _DEFAULT_BEDROCK
+
+
+def test_uipath_chat_vertex_no_args():
+    llm = UiPathChatVertex()
+    assert llm.model_name == _DEFAULT_VERTEX
+
+
+class TestOpenAIEnvVarOverride:
+    def test_env_var_overrides_openai_default(self, monkeypatch):
+        monkeypatch.setenv("UIPATH_MODEL_NAME", "gpt-5-preview")
+        llm = UiPathChat()
+        assert llm.model_name == "gpt-5-preview"
+
+    def test_env_var_does_not_leak_into_bedrock(self, monkeypatch):
+        monkeypatch.setenv("UIPATH_MODEL_NAME", "gpt-5-preview")
+        llm = UiPathChatBedrock()
+        assert llm.model_name == _DEFAULT_BEDROCK
+
+    def test_env_var_does_not_leak_into_vertex(self, monkeypatch):
+        monkeypatch.setenv("UIPATH_MODEL_NAME", "gpt-5-preview")
+        llm = UiPathChatGoogleGenerativeAI()
+        assert llm.model_name == _DEFAULT_VERTEX
+
+
+class TestExportsWithoutDefaults:
+    def test_anthropic_raises_without_model(self):
+        with pytest.raises(ValidationError, match="model"):
+            UiPathChatAnthropic()
+
+    def test_anthropic_vertex_raises_without_model(self):
+        with pytest.raises(ValidationError, match="model"):
+            UiPathChatAnthropicVertex()
+
+    def test_fireworks_raises_without_model(self):
+        with pytest.raises(ValidationError, match="model"):
+            UiPathChatFireworks()
+
+
+class TestReExportedClassIdentity:
+    def test_uipath_chat_is_upstream_class(self):
+        assert UiPathChat is _UpstreamUiPathChat
+
+    def test_uipath_chat_vertex_alias_matches_google(self):
+        assert UiPathChatVertex is UiPathChatGoogleGenerativeAI
+
+    def test_bedrock_converse_is_subclass_of_upstream(self):
+        assert issubclass(UiPathChatBedrockConverse, _UpstreamBedrockConverse)