diff --git a/inference/stages/load_prices.py b/inference/stages/load_prices.py
index add1f6f..5cf27cb 100644
--- a/inference/stages/load_prices.py
+++ b/inference/stages/load_prices.py
@@ -119,16 +119,18 @@ def _verify_arctic_fresh(universe_lib, date_str: str) -> None:
 
 
 def _connect_arctic(bucket: str) -> "tuple[object, object]":
-    """Open the ArcticDB universe + macro libraries. Hard-fail on unreachable."""
-    region = os.environ.get("AWS_REGION", "us-east-1")
-    uri = f"s3s://s3.{region}.amazonaws.com:{bucket}?path_prefix=arcticdb&aws_auth=true"
+    """Open the ArcticDB universe + macro libraries. Hard-fail on unreachable.
+
+    Delegates to ``alpha_engine_lib.arcticdb.open_universe_lib`` /
+    ``open_macro_lib`` (L2771 chokepoint). ``PipelineAbort`` is preserved
+    on the failure path so existing pipeline-level except handlers stay
+    correctly typed.
+    """
+    from alpha_engine_lib.arcticdb import open_universe_lib, open_macro_lib
     try:
-        arctic = adb.Arctic(uri)
-        return arctic.get_library("universe"), arctic.get_library("macro")
+        return open_universe_lib(bucket), open_macro_lib(bucket)
     except Exception as exc:
-        raise PipelineAbort(
-            f"ArcticDB unreachable at {uri}: {exc}"
-        ) from exc
+        raise PipelineAbort(str(exc)) from exc
 
 
 def load_price_data_from_arctic(
diff --git a/inference/stages/run_inference.py b/inference/stages/run_inference.py
index 13070aa..2f894dc 100644
--- a/inference/stages/run_inference.py
+++ b/inference/stages/run_inference.py
@@ -198,14 +198,8 @@ def _load_precomputed_features_from_arcticdb(
     inline compute_features. Those fallbacks masked a ``_run_gbm_inference``
     miswiring where ArcticDB was never actually consulted in production.
     """
-    region = os.environ.get("AWS_REGION", "us-east-1")
-    uri = f"s3s://s3.{region}.amazonaws.com:{ctx.bucket}?path_prefix=arcticdb&aws_auth=true"
-    try:
-        universe = adb.Arctic(uri).get_library("universe")
-    except Exception as exc:
-        raise RuntimeError(
-            f"ArcticDB universe library unreachable at {uri}: {exc}"
-        ) from exc
+    from alpha_engine_lib.arcticdb import open_universe_lib
+    universe = open_universe_lib(ctx.bucket)
 
     precomputed: dict[str, pd.Series] = {}
     n_err = 0
diff --git a/scripts/dry_run_meta_training.py b/scripts/dry_run_meta_training.py
index 4d85cef..5497230 100644
--- a/scripts/dry_run_meta_training.py
+++ b/scripts/dry_run_meta_training.py
@@ -70,9 +70,8 @@ def pull_from_arcticdb(local_dir: Path) -> int:
     import pandas as pd
     import boto3
 
-    region = os.environ.get("AWS_REGION", "us-east-1")
-    uri = f"s3s://s3.{region}.amazonaws.com:{BUCKET}?path_prefix={ARCTIC_PREFIX}&aws_auth=true"
-    arctic = _adb.Arctic(uri)
+    from alpha_engine_lib.arcticdb import open_arctic
+    arctic = open_arctic(BUCKET)
     universe = arctic.get_library("universe")
     macro_lib = arctic.get_library("macro")
 
diff --git a/store/arctic_reader.py b/store/arctic_reader.py
index c971815..b8bb6df 100644
--- a/store/arctic_reader.py
+++ b/store/arctic_reader.py
@@ -32,10 +32,9 @@
 
 
 def _get_arctic(bucket: str) -> adb.Arctic:
-    """Create ArcticDB connection."""
-    region = os.environ.get("AWS_REGION", "us-east-1")
-    uri = f"s3s://s3.{region}.amazonaws.com:{bucket}?path_prefix={ARCTIC_PREFIX}&aws_auth=true"
-    return adb.Arctic(uri)
+    """Create ArcticDB connection via the lib chokepoint (L2771)."""
+    from alpha_engine_lib.arcticdb import open_arctic
+    return open_arctic(bucket)
 
 
 def download_from_arctic(
diff --git a/tests/test_arctic_reader.py b/tests/test_arctic_reader.py
index 9a847c6..47a4168 100644
--- a/tests/test_arctic_reader.py
+++ b/tests/test_arctic_reader.py
@@ -10,9 +10,22 @@
 
 @pytest.fixture
 def fake_arcticdb(monkeypatch):
-    """Replace store.arctic_reader.adb with a controllable mock."""
+    """Replace the ``arcticdb`` module singleton's ``Arctic`` class with a
+    controllable mock. Patches at the singleton level so BOTH direct
+    ``import arcticdb as adb; adb.Arctic(...)`` callers AND the
+    ``alpha_engine_lib.arcticdb._import_arcticdb()`` lazy-import path
+    (used by ``open_arctic`` / ``open_universe_lib`` / ``open_macro_lib``)
+    pick up the mock. Without singleton-level patching, a lib-routed
+    call would bypass the mock and hit real S3 (post-L2771 chokepoint
+    migration)."""
+    import arcticdb as _real_arcticdb
     import store.arctic_reader as mod
     fake = MagicMock(name="arcticdb")
+    # Patch on the actual arcticdb module attribute — caught by both
+    # the consumer's `adb.Arctic(...)` and the lib's `open_arctic(...)`.
+    monkeypatch.setattr(_real_arcticdb, "Arctic", fake.Arctic)
+    # Also patch the consumer module's local ``adb`` reference for any
+    # legacy callers that still use it directly outside of `_get_arctic`.
     monkeypatch.setattr(mod, "adb", fake)
     return fake