fix: resolve real bedrock backing model for BYO aliases in factory

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
+- BYO AWS Bedrock backing-model resolution now reads the authoritative `byomDetails.customerModel` field that LLM Gateway discovery exposes for "add your own" (BYOMAdded) connections (LLM-3900). This is the upstream model the customer configured; `get_chat_model` uses it as `base_model_id`/`provider` for capability detection while the connection alias is still sent as `model_id` for gateway routing. Replaces the earlier speculative `byomDetails.baseModel`/`backingModel` lookups, which guessed at a field that did not yet exist. When `customerModel` is absent (UiPath-owned models) it falls back to the discovery `modelName`, which is itself the real model id.
+
 ## [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

@@ -4,6 +4,10 @@
 from pydantic import Field, model_validator
 
 from uipath_langchain_client.base_client import UiPathBaseChatModel
+from uipath_langchain_client.clients.bedrock.model_resolution import (
+    apply_backing_model_detection_hints,
+    provider_from_model,
+)
 from uipath_langchain_client.settings import (
     ApiFlavor,
     ApiType,
@@ -48,6 +52,47 @@ def _patched_format_data_content_block(block: dict) -> dict:
     ) from e
 
 
+def _setup_model_id_and_bedrock_hints(values: Any) -> Any:
+    if not isinstance(values, dict):
+        return values
+
+    updated = values
+    if "model_id" not in updated:
+        model = updated.get("model") or updated.get("model_name")
+        if model:
+            updated = {**updated, "model_id": model}
+
+    try:
+        base_model_id = updated.get("base_model_id") or updated.get("base_model")
+        if base_model_id and "provider" not in updated:
+            provider = provider_from_model(base_model_id)
+            if provider:
+                updated = {**updated, "provider": provider}
+
+        if "base_model_id" in updated or "base_model" in updated:
+            return updated
+
+        settings = updated.get("client_settings") or updated.get("settings")
+        model = updated.get("model") or updated.get("model_name") or updated.get("model_id")
+        if settings is None or model is None:
+            return updated
+
+        model_info = settings.get_model_info(
+            model,
+            byo_connection_id=updated.get("byo_connection_id"),
+        )
+        hints: dict[str, Any] = {}
+        apply_backing_model_detection_hints(hints, model_info)
+        if not hints:
+            return updated
+
+        updated = {**updated, **{k: v for k, v in hints.items() if k not in updated}}
+    except Exception:
+        return updated
+
+    return updated
+
+
 class UiPathChatBedrockConverse(UiPathBaseChatModel, ChatBedrockConverse):  # type: ignore[override]
     api_config: UiPathAPIConfig = UiPathAPIConfig(
         api_type=ApiType.COMPLETIONS,
@@ -65,11 +110,7 @@ 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_and_bedrock_hints(values)
 
     @model_validator(mode="after")
     def setup_uipath_client(self) -> Self:
@@ -94,11 +135,7 @@ 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_and_bedrock_hints(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 +1,94 @@
+"""Bedrock backing-model and provider resolution.
+
+Pure string/dict helpers that derive the real upstream Bedrock model id (and its
+provider) from an LLM Gateway discovery record. Kept free of ``botocore`` /
+``langchain_aws`` so they can be imported and tested without the ``bedrock`` extra,
+and so both the factory and the Bedrock clients depend on this module rather than on
+each other.
+"""
+
+from typing import Any
+
+_BEDROCK_REGION_PREFIXES = (
+    "eu.",
+    "us.",
+    "us-gov.",
+    "apac.",
+    "sa.",
+    "amer.",
+    "global.",
+    "jp.",
+    "au.",
+)
+
+
+def _normalize_model_id(model_id: Any) -> str | None:
+    if not isinstance(model_id, str):
+        return None
+
+    model_id = model_id.strip()
+    if not model_id:
+        return None
+
+    foundation_model_marker = "/foundation-model/"
+    if foundation_model_marker in model_id:
+        model_id = model_id.rsplit(foundation_model_marker, 1)[1]
+
+    model_id_without_region = model_id
+    for region_prefix in _BEDROCK_REGION_PREFIXES:
+        if model_id_without_region.startswith(region_prefix):
+            model_id_without_region = model_id_without_region[len(region_prefix) :]
+            break
+
+    if "." not in model_id_without_region:
+        return None
+
+    provider = model_id_without_region.split(".", 1)[0]
+    if not provider or " " in provider or "/" in provider:
+        return None
+
+    return model_id
+
+
+def _resolve_backing_model_id(model_info: dict[str, Any]) -> str | None:
+    byo_details = model_info.get("byomDetails") or {}
+
+    candidates = (
+        # Authoritative source: the upstream model the customer configured for a
+        # BYO ("add your own") connection. LLM Gateway discovery exposes it as
+        # byomDetails.customerModel (LLM-3900). For UiPath-owned models it is
+        # absent and we fall back to the discovery model name (the alias the
+        # factory was instantiated with, which is itself the real model id).
+        byo_details.get("customerModel"),
+        model_info.get("modelName"),
+    )
+    for candidate in candidates:
+        backing_model_id = _normalize_model_id(candidate)
+        if backing_model_id:
+            return backing_model_id
+    return None
+
+
+def provider_from_model(base_model_id: str | None) -> str | None:
+    base_model_id = _normalize_model_id(base_model_id)
+    if not base_model_id:
+        return None
+    model_id_without_region = base_model_id
+    for region_prefix in _BEDROCK_REGION_PREFIXES:
+        if model_id_without_region.startswith(region_prefix):
+            model_id_without_region = model_id_without_region[len(region_prefix) :]
+            break
+    provider = model_id_without_region.split(".", 1)[0]
+    return provider
+
+
+def apply_backing_model_detection_hints(
+    model_kwargs: dict[str, Any], model_info: dict[str, Any]
+) -> None:
+    # These fields are read by both Invoke and Converse clients to determine vendor
+    backing_model_id = _resolve_backing_model_id(model_info)
+    if backing_model_id:
+        model_kwargs.setdefault("base_model_id", backing_model_id)
+    provider = provider_from_model(backing_model_id)
+    if provider:
+        model_kwargs.setdefault("provider", provider)

packages/uipath_langchain_client/src/uipath_langchain_client/factory.py

@@ -205,20 +205,26 @@ 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,
+                )
 
+            from uipath_langchain_client.clients.bedrock.model_resolution import (
+                apply_backing_model_detection_hints,
+            )
+
+            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 +1,83 @@
+"""Unit tests for Bedrock backing-model resolution.
+
+Exercised through the module's public surface (``apply_backing_model_detection_hints``
+and ``provider_from_model``); the internal ``_resolve_backing_model_id`` /
+``_normalize_model_id`` helpers are covered transitively by the hints they produce.
+"""
+
+import pytest
+from uipath_langchain_client.clients.bedrock.model_resolution import (
+    apply_backing_model_detection_hints,
+    provider_from_model,
+)
+
+
+class TestApplyBackingModelDetectionHints:
+    def test_byo_uses_customer_model(self):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {
+                "modelName": "AWS - Bedrock",
+                "byomDetails": {
+                    "customerModel": "anthropic.claude-sonnet-4-5-20250929-v1:0",
+                    "integrationServiceConnectionId": "conn-x",
+                },
+            },
+        )
+        assert kwargs["base_model_id"] == "anthropic.claude-sonnet-4-5-20250929-v1:0"
+        assert kwargs["provider"] == "anthropic"
+
+    def test_uipath_owned_uses_model_name(self):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(
+            kwargs,
+            {
+                "modelName": "anthropic.claude-3-5-sonnet-20240620-v1:0",
+                "byomDetails": None,
+            },
+        )
+        assert kwargs["base_model_id"] == "anthropic.claude-3-5-sonnet-20240620-v1:0"
+        assert kwargs["provider"] == "anthropic"
+
+    def test_falls_back_to_model_name(self):
+        kwargs: dict = {}
+        apply_backing_model_detection_hints(kwargs, {"modelName": "amazon.nova-pro-v1:0"})
+        assert kwargs["base_model_id"] == "amazon.nova-pro-v1:0"
+        assert kwargs["provider"] == "amazon"
+
+    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"
+
+
+@pytest.mark.parametrize(
+    "model_id,expected",
+    [
+        ("anthropic.claude-sonnet-4-5-20250929-v1:0", "anthropic"),
+        ("global.anthropic.claude-sonnet-4-6", "anthropic"),
+        ("amazon.nova-pro-v1:0", "amazon"),
+        ("AWS - Bedrock", None),
+        ("my-claude-sonnet-4-5", None),
+        (None, None),
+    ],
+)
+def test_provider_from_model(model_id, expected):
+    assert provider_from_model(model_id) == expected