diff --git a/app/api/api_v1/routers/search.py b/app/api/api_v1/routers/search.py
index 87d5a28d..c621f006 100644
--- a/app/api/api_v1/routers/search.py
+++ b/app/api/api_v1/routers/search.py
@@ -157,7 +157,7 @@ def search_documents(
     )
 
     if not validate_corpora_ids(db, allowed_corpora_ids):
-        msg = "One or more of the given corpora do not exist in the database."
+        msg = "Error validating corpora IDs."
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail=msg,
diff --git a/app/db/crud/helpers/validate.py b/app/db/crud/helpers/validate.py
index 05a158c9..b017bf6b 100644
--- a/app/db/crud/helpers/validate.py
+++ b/app/db/crud/helpers/validate.py
@@ -1,4 +1,5 @@
 import logging
+from typing import Optional, cast
 
 from db_client.models.dfce.family import Corpus
 from sqlalchemy import distinct, select
@@ -7,16 +8,23 @@
 _LOGGER = logging.getLogger(__name__)
 
 
-def validate_corpora_ids(db: Session, allowed_corpora_ids: list[str]) -> bool:
-    """Validate whether all given corpus IDs exist in the DB.
+def validate_corpora_ids(
+    db: Session, corpora_ids: list[str], allowed_corpora_ids: Optional[list[str]] = None
+) -> bool:
+    """Validate all given corpus IDs against a list of allowed corpora.
 
     :param Session db: The DB session to connect to.
-    :param list[str] allowed_corpora_ids: The corpus import IDs we want
-        to validate.
-    :return bool: Return whether or not all the corpora exist in the DB.
+    :param list[str] corpora_ids: The corpus import IDs we want to
+        validate.
+    :param Optional[list[str]] allowed_corpora_ids: The corpus import
+        IDs we want to validate against.
+    :return bool: Return whether or not all the corpora are valid.
     """
-    existing_corpora_in_db = db.scalars(select(distinct(Corpus.import_id))).all()
-    validate_success = all(
-        corpus in allowed_corpora_ids for corpus in existing_corpora_in_db
-    )
+    if allowed_corpora_ids is None:
+        allowed_corpora_ids = cast(
+            list, db.scalars(select(distinct(Corpus.import_id))).all()
+        )
+        _LOGGER.info(allowed_corpora_ids)  # TODO remove in part 2.
+
+    validate_success = all(corpus in allowed_corpora_ids for corpus in corpora_ids)
     return validate_success
diff --git a/pyproject.toml b/pyproject.toml
index a3ffe3c9..cc74cc11 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "navigator_backend"
-version = "1.16.2"
+version = "1.16.3"
 description = ""
 authors = ["CPR-dev-team <tech@climatepolicyradar.org>"]
 packages = [{ include = "app" }, { include = "tests" }]
diff --git a/tests/search/vespa/test_search_raises_on_token_errors.py b/tests/search/vespa/test_search_raises_on_token_errors.py
index 7bee883d..6c0073d8 100644
--- a/tests/search/vespa/test_search_raises_on_token_errors.py
+++ b/tests/search/vespa/test_search_raises_on_token_errors.py
@@ -33,10 +33,7 @@ def test_search_with_invalid_corpus_id_in_token(
             expected_status_code=status.HTTP_400_BAD_REQUEST,
         )
 
-        assert (
-            response["detail"]
-            == "One or more of the given corpora do not exist in the database."
-        )
+        assert response["detail"] == "Error validating corpora IDs."
 
 
 @pytest.mark.search