diff --git a/src/bioetl/domain/ports/workflow_foreign_key_reconciliation.py b/src/bioetl/domain/ports/workflow_foreign_key_reconciliation.py
index 27d1e43a2c..eb0febf49a 100644
--- a/src/bioetl/domain/ports/workflow_foreign_key_reconciliation.py
+++ b/src/bioetl/domain/ports/workflow_foreign_key_reconciliation.py
@@ -27,6 +27,10 @@ class ForeignKeyReconciliationRequest:
     nulls_equal: bool = False
 
     def __post_init__(self) -> None:
+        self._validate_required_fields()
+        self._validate_composite_keys()
+
+    def _validate_required_fields(self) -> None:
         if not self.source_table.strip():
             raise ValueError("source_table cannot be empty")
         if not self.reference_table.strip():
@@ -37,24 +41,20 @@ def __post_init__(self) -> None:
             raise ValueError("reference_key cannot be empty")
         if not self.primary_keys:
             raise ValueError("primary_keys cannot be empty")
+
+    def _validate_composite_keys(self) -> None:
         if self.source_keys is None and self.reference_keys is None:
             return
         if self.source_keys is None or self.reference_keys is None:
-            raise ValueError(
-                "source_keys and reference_keys must be provided together"
-            )
+            raise ValueError("source_keys and reference_keys must be provided together")
         if not self.source_keys or not self.reference_keys:
             raise ValueError("source_keys and reference_keys cannot be empty")
         if len(self.source_keys) != len(self.reference_keys):
-            raise ValueError(
-                "source_keys and reference_keys must have the same length"
-            )
+            raise ValueError("source_keys and reference_keys must have the same length")
         if self.source_keys[0].strip() != self.source_key.strip():
             raise ValueError("source_key must match the first source_keys entry")
         if self.reference_keys[0].strip() != self.reference_key.strip():
-            raise ValueError(
-                "reference_key must match the first reference_keys entry"
-            )
+            raise ValueError("reference_key must match the first reference_keys entry")
 
     @property
     def effective_source_keys(self) -> tuple[str, ...]:
diff --git a/src/bioetl/interfaces/cli/commands/domains/health/observability_backend_process.py b/src/bioetl/interfaces/cli/commands/domains/health/observability_backend_process.py
index 5a6c38f08e..1208f4d1b0 100644
--- a/src/bioetl/interfaces/cli/commands/domains/health/observability_backend_process.py
+++ b/src/bioetl/interfaces/cli/commands/domains/health/observability_backend_process.py
@@ -136,7 +136,7 @@ def _build_detached_backend_env(
     current_env: dict[str, str] | None = None,
 ) -> dict[str, str]:
     """Ensure detached backend subprocess can import the src-layout package."""
-    env = dict(current_env if current_env is not None else getattr(os, "environ"))
+    env = dict(current_env if current_env is not None else os.environ)
     src_root = Path(__file__).resolve().parents[6]
     existing_pythonpath = env.get("PYTHONPATH", "").strip()
     pythonpath_parts = [str(src_root)]
diff --git a/tests/unit/infrastructure/adapters/common/test_response_shapes.py b/tests/unit/infrastructure/adapters/common/test_response_shapes.py
index 999874b855..2285a8691d 100644
--- a/tests/unit/infrastructure/adapters/common/test_response_shapes.py
+++ b/tests/unit/infrastructure/adapters/common/test_response_shapes.py
@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+from collections import OrderedDict
+
 from bioetl.infrastructure.adapters.common.response_shapes import (
     extract_response_items,
     extract_response_mapping,
@@ -40,3 +42,11 @@ def test_extract_response_text_returns_only_string_values() -> None:
     assert extract_response_text({"nextCursor": "cursor-1"}, "nextCursor") == "cursor-1"
     assert extract_response_text({"nextCursor": 10}, "nextCursor") is None
     assert extract_response_text({}, "nextCursor") is None
+
+
+def test_extract_response_mapping_handles_various_edge_cases() -> None:
+    assert extract_response_mapping({"meta": None}, "meta") is None
+    assert extract_response_mapping({"meta": "string_not_mapping"}, "meta") is None
+
+    ordered_map = OrderedDict([("a", 1), ("b", 2)])
+    assert extract_response_mapping({"meta": ordered_map}, "meta") == ordered_map