fix: resolve real customer model for BYO aliases in bedrock factory (#103)

Author: andreiancuta-uipath

packages/uipath_langchain_client/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 All notable changes to `uipath_langchain_client` will be documented in this file.
 
+## [1.15.1] - 2026-06-30
+
+### Fixed
+- Bedrock clients now determine the provider and base model from the underlying customer model, in the case of BYOM configurations. This fixes a bug where agents with Bedrock BYOM configurations with custom aliases would fail to run.
+
 ## [1.15.0] - 2026-06-25
 
 ### Added

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__ = "1.15.0"
+__version__ = "1.15.1"

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

@@ -48,6 +48,14 @@ def _patched_format_data_content_block(block: dict) -> dict:
     ) from e
 
 
+def _setup_model_id(values: Any) -> Any:
+    if isinstance(values, dict) and "model_id" not in values:
+        model = values.get("model") or values.get("model_name")
+        if model:
+            values = {**values, "model_id": model}
+    return values
+
+
 class UiPathChatBedrockConverse(UiPathBaseChatModel, ChatBedrockConverse):  # type: ignore[override]
     api_config: UiPathAPIConfig = UiPathAPIConfig(
         api_type=ApiType.COMPLETIONS,
@@ -65,11 +73,7 @@ class UiPathChatBedrockConverse(UiPathBaseChatModel, ChatBedrockConverse):  # ty
     @model_validator(mode="before")
     @classmethod
     def setup_model_id(cls, values: Any) -> Any:
-        if isinstance(values, dict) and "model_id" not in values:
-            model = values.get("model") or values.get("model_name")
-            if model:
-                values = {**values, "model_id": model}
-        return values
+        return _setup_model_id(values)
 
     @model_validator(mode="after")
     def setup_uipath_client(self) -> Self:
@@ -94,11 +98,7 @@ class UiPathChatBedrock(UiPathBaseChatModel, ChatBedrock):  # type: ignore[overr
     @model_validator(mode="before")
     @classmethod
     def setup_model_id(cls, values: Any) -> Any:
-        if isinstance(values, dict) and "model_id" not in values:
-            model = values.get("model") or values.get("model_name")
-            if model:
-                values = {**values, "model_id": model}
-        return values
+        return _setup_model_id(values)
 
     @model_validator(mode="after")
     def setup_uipath_client(self) -> Self:

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

@@ -0,0 +1,53 @@
+"""Bedrock backing-model and provider resolution."""
+
+from typing import Any
+
+_BEDROCK_REGIONS = (
+    "eu",
+    "us",
+    "us-gov",
+    "apac",
+    "sa",
+    "amer",
+    "global",
+    "jp",
+    "au",
+)
+
+
+def _split_model_id(model_id: str) -> tuple[str, str] | None:
+    model_id = model_id.strip()
+    parts = model_id.split(".")
+
+    if parts[0] in _BEDROCK_REGIONS:
+        parts = parts[1:]
+
+    if len(parts) < 2:
+        return None
+
+    provider = parts[0]
+    if not provider or " " in provider or "/" in provider:
+        return None
+
+    return model_id, provider
+
+
+def _resolve_backing_model(model_info: dict[str, Any]) -> tuple[str, str] | None:
+    byo_details = model_info.get("byomDetails") or {}
+    customer_model = byo_details.get("customerModel")
+    if isinstance(customer_model, str):
+        return _split_model_id(customer_model)
+    return None
+
+
+def apply_backing_model_detection_hints(
+    model_kwargs: dict[str, Any], model_info: dict[str, Any]
+) -> None:
+    if "base_model_id" in model_kwargs or "base_model" in model_kwargs:
+        return
+    backing = _resolve_backing_model(model_info)
+    if not backing:
+        return
+    base_model_id, provider = backing
+    model_kwargs["base_model_id"] = base_model_id
+    model_kwargs.setdefault("provider", provider)

packages/uipath_langchain_client/src/uipath_langchain_client/factory.py

@@ -26,6 +26,9 @@
     UiPathBaseChatModel,
     UiPathBaseEmbeddings,
 )
+from uipath_langchain_client.clients.bedrock.model_resolution import (
+    apply_backing_model_detection_hints,
+)
 from uipath_langchain_client.settings import (
     API_FLAVOR_TO_VENDOR_TYPE,
     BYOM_TO_ROUTING_FLAVOR,
@@ -205,20 +208,22 @@ def get_chat_model(
                     **model_kwargs,
                 )
 
-            if api_flavor == ApiFlavor.INVOKE:
-                if model_family == ModelFamily.ANTHROPIC_CLAUDE:
-                    from uipath_langchain_client.clients.bedrock.chat_models import (
-                        UiPathChatAnthropicBedrock,
-                    )
-
-                    return UiPathChatAnthropicBedrock(
-                        model=model_name,
-                        settings=client_settings,
-                        byo_connection_id=byo_connection_id,
-                        model_details=model_details,
-                        **model_kwargs,
-                    )
+            if api_flavor == ApiFlavor.INVOKE and model_family == ModelFamily.ANTHROPIC_CLAUDE:
+                from uipath_langchain_client.clients.bedrock.chat_models import (
+                    UiPathChatAnthropicBedrock,
+                )
 
+                return UiPathChatAnthropicBedrock(
+                    model=model_name,
+                    settings=client_settings,
+                    byo_connection_id=byo_connection_id,
+                    model_details=model_details,
+                    **model_kwargs,
+                )
+
+            apply_backing_model_detection_hints(model_kwargs, model_info)
+
+            if api_flavor == ApiFlavor.INVOKE:
                 from uipath_langchain_client.clients.bedrock.chat_models import (
                     UiPathChatBedrock,
                 )

tests/langchain/clients/bedrock/test_model_resolution.py

@@ -0,0 +1,85 @@
+"""Unit tests for Bedrock backing-model resolution."""
+
+import pytest
+from uipath_langchain_client.clients.bedrock.model_resolution import (
+    apply_backing_model_detection_hints,
+)
+
+
+class TestApplyBackingModelDetectionHints:
+    @pytest.mark.parametrize(
+        "customer_model,expected_provider",
+        [
+            ("anthropic.claude-sonnet-4-5-20250929-v1:0", "anthropic"),
+            ("global.anthropic.claude-sonnet-4-6", "anthropic"),
+            ("amazon.nova-pro-v1:0", "amazon"),
+        ],
+    )
+    def test_byo_uses_customer_model(self, customer_model, expected_provider):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {
+                "modelName": "AWS - Bedrock",
+                "byomDetails": {
+                    "customerModel": customer_model,
+                    "integrationServiceConnectionId": "conn-x",
+                },
+            },
+        )
+        assert kwargs["base_model_id"] == customer_model
+        assert kwargs["provider"] == expected_provider
+
+    def test_unparseable_customer_model_sets_no_hints(self):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {
+                "modelName": "AWS - Bedrock",
+                "byomDetails": {"customerModel": "my-claude-sonnet-4-5"},
+            },
+        )
+        assert "base_model_id" not in kwargs
+        assert "provider" not in kwargs
+
+    def test_non_byo_model_sets_no_hints(self):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {
+                "modelName": "anthropic.claude-3-5-sonnet-20240620-v1:0",
+                "byomDetails": None,
+            },
+        )
+        assert "base_model_id" not in kwargs
+        assert "provider" not in kwargs
+
+    def test_byo_alias_without_customer_model_sets_no_hints(self):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {
+                "modelName": "VeryCustomBedddrockAlias",
+                "byomDetails": {"integrationServiceConnectionId": "conn-x"},
+            },
+        )
+        assert "base_model_id" not in kwargs
+        assert "provider" not in kwargs
+
+    def test_does_not_override_caller_supplied_hints(self):
+        kwargs = {"base_model_id": "amazon.nova-pro-v1:0", "provider": "amazon"}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {"byomDetails": {"customerModel": "anthropic.claude-sonnet-4-5-20250929-v1:0"}},
+        )
+        assert kwargs["base_model_id"] == "amazon.nova-pro-v1:0"
+        assert kwargs["provider"] == "amazon"
+
+    def test_caller_base_model_alias_is_not_shadowed_by_base_model_id(self):
+        kwargs = {"base_model": "amazon.nova-pro-v1:0"}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {"byomDetails": {"customerModel": "anthropic.claude-sonnet-4-5-20250929-v1:0"}},
+        )
+        assert "base_model_id" not in kwargs
+        assert kwargs["base_model"] == "amazon.nova-pro-v1:0"

tests/langchain/features/test_factory_function.py

@@ -1,9 +1,16 @@
 from unittest.mock import MagicMock
 
 import pytest
+from uipath_langchain_client.clients.bedrock.chat_models import (
+    UiPathChatBedrock,
+    UiPathChatBedrockConverse,
+)
 from uipath_langchain_client.clients.normalized.chat_models import UiPathChat
 from uipath_langchain_client.clients.normalized.embeddings import UiPathEmbeddings
-from uipath_langchain_client.factory import get_chat_model, get_embedding_model
+from uipath_langchain_client.factory import (
+    get_chat_model,
+    get_embedding_model,
+)
 
 from tests.langchain.conftest import COMPLETION_MODEL_NAMES, EMBEDDING_MODEL_NAMES
 from uipath.llm_client.settings import ApiFlavor, UiPathBaseSettings, VendorType
@@ -379,3 +386,94 @@ def test_anthropic_messages_routes_to_uipath_chat_anthropic(
         )
         assert captured["vendor_type"] == VendorType.AWSBEDROCK
         assert captured["api_flavor"] == ApiFlavor.ANTHROPIC_MESSAGES
+
+
+_BYO_BEDROCK_CONVERSE = {
+    "modelName": "AWS - Bedrock",
+    "vendor": "AwsBedrock",
+    "modelFamily": None,
+    "apiFlavor": None,
+    "modelSubscriptionType": "BYOMAdded",
+    "byomDetails": {
+        "customerModel": "anthropic.claude-sonnet-4-5-20250929-v1:0",
+        "integrationServiceConnectionId": "conn-x",
+    },
+}
+_BYO_BEDROCK_INVOKE = {**_BYO_BEDROCK_CONVERSE, "apiFlavor": "AwsBedrockInvoke"}
+
+
+class TestBedrockFactoryBaseModel:
+    @pytest.fixture()
+    def client_settings(self):
+        import os
+        from unittest.mock import patch
+
+        from uipath.llm_client.settings.llmgateway import LLMGatewaySettings
+
+        env = {
+            "LLMGW_URL": "http://test-bedrock",
+            "LLMGW_SEMANTIC_ORG_ID": "org",
+            "LLMGW_SEMANTIC_TENANT_ID": "tenant",
+            "LLMGW_REQUESTING_PRODUCT": "test",
+            "LLMGW_REQUESTING_FEATURE": "test",
+            "LLMGW_ACCESS_TOKEN": "dummy-token",
+        }
+        with patch.dict(os.environ, env, clear=True):
+            return LLMGatewaySettings()
+
+    @pytest.fixture(autouse=True)
+    def _clear_discovery_cache(self):
+        UiPathBaseSettings._discovery_cache.clear()
+        yield
+        UiPathBaseSettings._discovery_cache.clear()
+
+    def _seed(self, client_settings, model_info):
+        key = client_settings._discovery_cache_key()
+        client_settings._discovery_cache[key] = [model_info]
+
+    def test_converse_byo_alias_gets_backing_base_model(self, client_settings):
+        self._seed(client_settings, _BYO_BEDROCK_CONVERSE)
+        model = get_chat_model(
+            "AWS - Bedrock",
+            byo_connection_id="conn-x",
+            client_settings=client_settings,
+        )
+        assert isinstance(model, UiPathChatBedrockConverse)
+        assert model.model_id == "AWS - Bedrock"
+        assert model.base_model_id == "anthropic.claude-sonnet-4-5-20250929-v1:0"
+        assert model.supports_tool_choice_values == ("auto", "any", "tool")
+
+        from langchain_core.tools import tool
+
+        @tool
+        def ping() -> str:
+            """ping."""
+            return "pong"
+
+        model.bind_tools([ping], tool_choice="any")
+
+    def test_converse_direct_construction_takes_explicit_backing_model(self, client_settings):
+        self._seed(client_settings, _BYO_BEDROCK_CONVERSE)
+        model = UiPathChatBedrockConverse(
+            model="AWS - Bedrock",
+            settings=client_settings,
+            byo_connection_id="conn-x",
+            base_model="anthropic.claude-sonnet-4-5-20250929-v1:0",
+            provider="anthropic",
+        )
+        assert model.base_model_id == "anthropic.claude-sonnet-4-5-20250929-v1:0"
+        assert model.provider == "anthropic"
+        assert model.supports_tool_choice_values == ("auto", "any", "tool")
+
+    def test_invoke_byo_alias_gets_provider(self, client_settings):
+        self._seed(client_settings, _BYO_BEDROCK_INVOKE)
+        model = get_chat_model(
+            "AWS - Bedrock",
+            byo_connection_id="conn-x",
+            client_settings=client_settings,
+        )
+        assert isinstance(model, UiPathChatBedrock)
+        assert model.model_id == "AWS - Bedrock"
+        assert model.base_model_id == "anthropic.claude-sonnet-4-5-20250929-v1:0"
+        assert model.provider == "anthropic"
+        assert model._get_provider() == "anthropic"