UN-2896 [FIX] Self-review: close the remaining deprecated-adapter paths

- platform-service: the adapter_instance route's blanket `except Exception` re-wrapped every APIError as a 500, so both the new deprecation error and the pre-existing "not found" reported as server errors and logged a traceback. Re-raise APIError untouched, as the neighbouring route does. - Move the adapter_id check into AdapterInstanceSerializer.validate: adapter_id is writable, so update/partial_update could set a deprecated id that create rejected. - Default profile creation and the project-import warning gated on is_usable alone, letting a deprecated default land in a new profile without passing through the serializer. - set_default_triad accepted a deprecated adapter as a user default straight from the API. - New is_adapter_selectable() states the rule once: usable, available, and not deprecated. - DefaultTriad: disable deprecated options instead of dropping them. Filtering emptied adapterList for an org whose adapters are all deprecated, which gated the effect that loads the current defaults, and left the current default rendering as a bare UUID. Claude-Session: https://claude.ai/code/session_01DXuiGyUwXyU1EVQBeMHppe
Deepak-Kesavan · Aug 31, 2026 · Aug 31, 2026 · Sep 1, 2026 · Sep 1, 2026 · Sep 7, 2026
commit 4cecc1a60fe669c29c0479bb0b8c887dabec391b
diff --git a/backend/adapter_processor_v2/adapter_processor.py b/backend/adapter_processor_v2/adapter_processor.py
@@ -13,6 +13,7 @@
 from adapter_processor_v2.deprecated_adapters import (
     get_deprecation_message,
     is_adapter_deprecated,
+    is_adapter_selectable,
 )
 from adapter_processor_v2.exceptions import (
     AdapterNotFound,
@@ -210,6 +211,14 @@ def __fetch_adapters_by_key_value(key: str, value: Any) -> Adapter:
         adapters = adapter_kit.get_adapters_list()
         return [iterate for iterate in adapters if iterate[key] == value]
 
+    @staticmethod
+    def _resolve_selectable_adapter(adapter_pk: str) -> AdapterInstance:
+        """Adapter for ``adapter_pk``, refusing one that can no longer be chosen."""
+        adapter = AdapterInstance.objects.get(pk=adapter_pk)
+        if not is_adapter_selectable(adapter):
+            raise DeprecatedAdapter(get_deprecation_message(adapter.adapter_id))
+        return adapter
+
     @staticmethod
     def set_default_triad(default_triad: dict[str, str], user: User) -> None:
         try:
@@ -222,34 +231,38 @@ def set_default_triad(default_triad: dict[str, str], user: User) -> None:
             )
 
             if default_triad.get(AdapterKeys.LLM_DEFAULT, None):
-                user_default_adapter.default_llm_adapter = AdapterInstance.objects.get(
-                    pk=default_triad[AdapterKeys.LLM_DEFAULT]
+                user_default_adapter.default_llm_adapter = (
+                    AdapterProcessor._resolve_selectable_adapter(
+                        default_triad[AdapterKeys.LLM_DEFAULT]
+                    )
                 )
             if default_triad.get(AdapterKeys.EMBEDDING_DEFAULT, None):
                 user_default_adapter.default_embedding_adapter = (
-                    AdapterInstance.objects.get(
-                        pk=default_triad[AdapterKeys.EMBEDDING_DEFAULT]
+                    AdapterProcessor._resolve_selectable_adapter(
+                        default_triad[AdapterKeys.EMBEDDING_DEFAULT]
                     )
                 )
 
             if default_triad.get(AdapterKeys.VECTOR_DB_DEFAULT, None):
                 user_default_adapter.default_vector_db_adapter = (
-                    AdapterInstance.objects.get(
-                        pk=default_triad[AdapterKeys.VECTOR_DB_DEFAULT]
+                    AdapterProcessor._resolve_selectable_adapter(
+                        default_triad[AdapterKeys.VECTOR_DB_DEFAULT]
                     )
                 )
 
             if default_triad.get(AdapterKeys.X2TEXT_DEFAULT, None):
-                user_default_adapter.default_x2text_adapter = AdapterInstance.objects.get(
-                    pk=default_triad[AdapterKeys.X2TEXT_DEFAULT]
+                user_default_adapter.default_x2text_adapter = (
+                    AdapterProcessor._resolve_selectable_adapter(
+                        default_triad[AdapterKeys.X2TEXT_DEFAULT]
+                    )
                 )
 
             user_default_adapter.save()
 
             logger.info("Changed defaults successfully")
         except Exception as e:
             logger.error(f"Unable to save defaults because: {e}")
-            if isinstance(e, InValidAdapterId):
+            if isinstance(e, (InValidAdapterId, DeprecatedAdapter)):
                 raise e
             else:
                 raise InternalServiceError()

diff --git a/backend/adapter_processor_v2/deprecated_adapters.py b/backend/adapter_processor_v2/deprecated_adapters.py
@@ -40,6 +40,22 @@ def get_deprecation_metadata(adapter_id: str | None) -> dict[str, Any] | None:
     return dict(metadata) if metadata else None
 
 
+def is_adapter_selectable(adapter: Any) -> bool:
+    """Whether an ``AdapterInstance`` may back a new profile, default or config.
+
+    Covers the three ways an adapter stops being a valid choice: usage
+    exhausted (``is_usable``), withdrawn from the SDK (``is_available``), and
+    deprecated here. Existing selections are not re-validated against this —
+    they stay readable so users can see what to migrate off.
+    """
+    return bool(
+        adapter is not None
+        and adapter.is_usable
+        and adapter.is_available
+        and not is_adapter_deprecated(adapter.adapter_id)
+    )
+
+
 def get_deprecation_message(adapter_id: str | None) -> str:
     """User-facing reason ``adapter_id`` can no longer be used."""
     metadata = get_deprecation_metadata(adapter_id)

diff --git a/backend/adapter_processor_v2/serializers.py b/backend/adapter_processor_v2/serializers.py
@@ -5,7 +5,7 @@
 from cryptography.fernet import Fernet
 from django.conf import settings
 from rest_framework import serializers
-from rest_framework.serializers import ModelSerializer
+from rest_framework.serializers import ModelSerializer, ValidationError
 from tenant_account_v2.sharing_helpers import (
     serialize_group_refs,
     serialize_owner_refs,
@@ -15,6 +15,7 @@
 from adapter_processor_v2.adapter_processor import AdapterProcessor
 from adapter_processor_v2.constants import AdapterKeys
 from adapter_processor_v2.deprecated_adapters import (
+    get_deprecation_message,
     get_deprecation_metadata,
     is_adapter_deprecated,
 )
@@ -95,6 +96,19 @@ class AdapterInstanceSerializer(BaseAdapterSerializer):
     Used for CRUD other than listing
     """
 
+    def validate(self, attrs: dict[str, Any]) -> dict[str, Any]:
+        """Reject a deprecated adapter_id.
+
+        Sits on the serializer rather than the create view because
+        ``adapter_id`` is writable, so update/partial_update reach it too.
+        """
+        adapter_id = attrs.get(AdapterKeys.ADAPTER_ID)
+        if is_adapter_deprecated(adapter_id):
+            raise ValidationError(
+                {AdapterKeys.ADAPTER_ID: get_deprecation_message(adapter_id)}
+            )
+        return attrs
+
     def to_internal_value(self, data: dict[str, Any]) -> dict[str, Any]:
         if data.get(AdapterKeys.ADAPTER_METADATA, None):
             encryption_secret: str = settings.ENCRYPTION_KEY

diff --git a/backend/adapter_processor_v2/tests/test_deprecated_adapters.py b/backend/adapter_processor_v2/tests/test_deprecated_adapters.py
@@ -8,12 +8,14 @@
 from __future__ import annotations
 
 import pytest
+from rest_framework.serializers import ValidationError
 
 from adapter_processor_v2.adapter_processor import AdapterProcessor
 from adapter_processor_v2.deprecated_adapters import (
     DEPRECATED_ADAPTERS,
     get_deprecation_message,
     is_adapter_deprecated,
+    is_adapter_selectable,
 )
 from adapter_processor_v2.exceptions import DeprecatedAdapter
 from unstract.sdk1.adapters.adapterkit import Adapterkit
@@ -62,3 +64,48 @@ def test_deprecation_message_names_the_replacement():
 def test_unknown_adapter_is_not_deprecated():
     assert not is_adapter_deprecated("openai|some-uuid")
     assert not is_adapter_deprecated(None)
+
+
+class _FakeAdapter:
+    """Stand-in for AdapterInstance; is_adapter_selectable reads 4 fields."""
+
+    def __init__(self, adapter_id, is_usable=True, is_available=True):
+        self.adapter_id = adapter_id
+        self.is_usable = is_usable
+        self.is_available = is_available
+
+
+def test_selectable_adapter_passes():
+    assert is_adapter_selectable(_FakeAdapter("openai|some-uuid"))
+
+
+@pytest.mark.parametrize(
+    "adapter",
+    [
+        None,
+        _FakeAdapter(LLM_WHISPERER_V1),
+        _FakeAdapter("openai|some-uuid", is_usable=False),
+        _FakeAdapter("openai|some-uuid", is_available=False),
+    ],
+    ids=["none", "deprecated", "usage-exhausted", "withdrawn-from-sdk"],
+)
+def test_unselectable_adapters_are_refused(adapter):
+    """Guards default-profile creation and set_default_triad."""
+    assert not is_adapter_selectable(adapter)
+
+
+def test_serializer_rejects_deprecated_adapter_id():
+    """Covers create AND update/partial_update, since adapter_id is writable."""
+    from adapter_processor_v2.serializers import AdapterInstanceSerializer
+
+    serializer = AdapterInstanceSerializer()
+    with pytest.raises(ValidationError) as exc:
+        serializer.validate({"adapter_id": LLM_WHISPERER_V1})
+    assert "adapter_id" in exc.value.detail
+
+
+def test_serializer_allows_supported_adapter_id():
+    from adapter_processor_v2.serializers import AdapterInstanceSerializer
+
+    attrs = {"adapter_id": "llmwhisperer|a5e6b8af-3e1f-4a80-b006-d017e8e67f93"}
+    assert AdapterInstanceSerializer().validate(attrs) == attrs
diff --git a/backend/adapter_processor_v2/views.py b/backend/adapter_processor_v2/views.py
@@ -253,10 +253,9 @@ def create(self, request: Any) -> Response:
         ):
             use_platform_unstract_key = True
 
+        # Deprecated adapter_ids are rejected in AdapterInstanceSerializer.validate,
+        # which also covers update/partial_update.
         serializer.is_valid(raise_exception=True)
-        adapter_id = serializer.validated_data.get(AdapterKeys.ADAPTER_ID)
-        if is_adapter_deprecated(adapter_id):
-            raise DeprecatedAdapter(get_deprecation_message(adapter_id))
         adapter_type = serializer.validated_data.get(AdapterKeys.ADAPTER_TYPE)
         self._enforce_llm_creation_restriction(request, adapter_type)
 

diff --git a/backend/prompt_studio/prompt_studio_core_v2/prompt_studio_helper.py b/backend/prompt_studio/prompt_studio_core_v2/prompt_studio_helper.py
@@ -8,6 +8,7 @@
 
 from account_v2.constants import Common
 from account_v2.models import User
+from adapter_processor_v2.deprecated_adapters import is_adapter_selectable
 from adapter_processor_v2.models import AdapterInstance, UserDefaultAdapter
 from django.conf import settings
 from django.db import transaction
@@ -143,8 +144,8 @@ def create_default_profile_manager(user: User, tool_id: uuid) -> None:
             "vector_store": default_adapter.default_vector_db_adapter,
             "x2text": default_adapter.default_x2text_adapter,
         }
-        # A valid profile needs a usable default for every adapter type
-        if not all(adapter and adapter.is_usable for adapter in adapters.values()):
+        # A valid profile needs a selectable default for every adapter type
+        if not all(is_adapter_selectable(adapter) for adapter in adapters.values()):
             logger.info(
                 "Skipping default profile creation: "
                 "incomplete or unusable default adapters"
@@ -3137,7 +3138,7 @@ def validate_adapter_configuration(
                 ]
 
                 for adapter in adapters_to_check:
-                    if not adapter or not adapter.is_usable:
+                    if not is_adapter_selectable(adapter):
                         warning_message = (
                             "Some adapters may need to be configured before you can use "
                             "this project. Please check the profile settings."

diff --git a/frontend/src/components/settings/default-triad/DefaultTriad.jsx b/frontend/src/components/settings/default-triad/DefaultTriad.jsx
@@ -3,7 +3,6 @@ import { Button, Select, Typography } from "antd";
 import { useEffect, useState } from "react";
 import { useNavigate } from "react-router-dom";
 
-import { usableAdapters } from "../../../helpers/GetStaticData";
 import { fetchAllPages } from "../../../helpers/pagination";
 import { useAxiosPrivate } from "../../../hooks/useAxiosPrivate";
 import { useExceptionHandler } from "../../../hooks/useExceptionHandler.jsx";
@@ -67,7 +66,7 @@ function DefaultTriad() {
       url: `/api/v1/unstract/${sessionDetails?.orgId}/adapter/`,
     })
       .then((adapters) => {
-        setAdapterList(usableAdapters(adapters));
+        setAdapterList(adapters);
       })
       .catch((err) => {
         setAlertDetails(
@@ -203,8 +202,14 @@ function DefaultTriad() {
                     {dropdownData
                       .filter((data) => data?.adapter_type === type)
                       .map((data) => (
-                        <Option key={data?.id} value={data?.id}>
-                          {data?.adapter_name}
+                        <Option
+                          key={data?.id}
+                          value={data?.id}
+                          disabled={data?.is_deprecated}
+                        >
+                          {data?.is_deprecated
+                            ? `${data?.adapter_name} (deprecated)`
+                            : data?.adapter_name}
                         </Option>
                       ))}
                   </Select>

diff --git a/platform-service/src/unstract/platform_service/controller/platform.py b/platform-service/src/unstract/platform_service/controller/platform.py
@@ -390,6 +390,11 @@ def adapter_instance() -> Any:
             f"{adapter_instance_id}, Error: {msg}"
         )
         raise APIError(message=msg, code=403)
+    except APIError:
+        # Already carries its own status and user-facing message (adapter not
+        # found, adapter deprecated); re-wrapping would report it as a 500 and
+        # log a traceback for what is a client-side condition.
+        raise
     except Exception as e:
         msg = f"Error while getting db adapter settings for {adapter_instance_id}: {e}"
         raise APIError(message=msg)