diff --git a/plugins/cfg_impact/pyproject.toml b/plugins/cfg_impact/pyproject.toml
index 0450ae9..ba37c16 100644
--- a/plugins/cfg_impact/pyproject.toml
+++ b/plugins/cfg_impact/pyproject.toml
@@ -1,13 +1,13 @@
 [project]
 name = "cfgit-impact"
-version = "0.1.2"
+version = "0.1.3"
 description = "Optional cfgit plugin for deterministic system-impact summaries and opt-in LLM narration of database record diffs"
 readme = "README.md"
 requires-python = ">=3.11"
 license = "Apache-2.0"
 authors = [{ name = "Mohammad Ausaf" }]
 dependencies = [
-  "cfgit>=0.1.2,<0.2.0",
+  "cfgit>=0.1.3,<0.2.0",
   "httpx>=0.27",
 ]
 
diff --git a/pyproject.toml b/pyproject.toml
index 64903b9..e421544 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "cfgit"
-version = "0.1.2"
+version = "0.1.3"
 description = "Git-style history, diff, drift detection, and rollback for live database records without migrating or owning your datastore"
 readme = "README.md"
 requires-python = ">=3.11"
diff --git a/src/cfg/core/config.py b/src/cfg/core/config.py
index a2998e8..31e66eb 100644
--- a/src/cfg/core/config.py
+++ b/src/cfg/core/config.py
@@ -308,13 +308,7 @@ def _resolve_uri(raw: str, *, env_name: str) -> str:
     if raw.startswith("env:"):
         key = raw[4:]
         value = os.environ.get(key)
-        if value:
-            return value
-        if env_name == "dev":
-            fallback = os.environ.get("MONGODB_URI")
-            if fallback:
-                return fallback
-        return ""
+        return value or ""
     return raw
 
 
diff --git a/src/cfg/core/engine.py b/src/cfg/core/engine.py
index 5027e8c..93014d3 100644
--- a/src/cfg/core/engine.py
+++ b/src/cfg/core/engine.py
@@ -1082,7 +1082,7 @@ def resolve_ref(self, ref: RecordRef, value: str) -> dict[str, Any]:
         else:
             rows = self.adapter.query_history(collection=ref.collection, record_id=ref.record_id, ref=value, with_doc=True)
         if not rows:
-            raise NoSuchConfig(f"ref not found: {value}")
+            raise NoSuchConfig(_ref_not_found_message(value))
         if len(rows) > 1:
             raise ValueError(f"ambiguous ref: {value}")
         return rows[0]
@@ -1358,6 +1358,12 @@ def _branch_plan_result(plan: dict[str, Any], *, state: str | None = None) -> di
     return result
 
 
+def _ref_not_found_message(value: str) -> str:
+    if value.isdecimal():
+        return f"ref not found: {value} (sequence refs use @{value}; bare values are oid prefixes)"
+    return f"ref not found: {value}"
+
+
 def _parse_branch_range(value: str, default_branch: str) -> tuple[str, str]:
     raw = str(value or "").strip()
     if ".." not in raw:
diff --git a/tests/test_config.py b/tests/test_config.py
index 316bb60..b47e918 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -32,3 +32,29 @@ def test_load_config_reads_branch_settings(tmp_path) -> None:
     assert project.branches.enabled is True
     assert project.branches.refs_collection == "cfgit_refs_custom"
     assert project.branches.default_branch == "main"
+
+
+def test_env_uri_does_not_fallback_to_generic_mongodb_uri(tmp_path, monkeypatch) -> None:
+    monkeypatch.delenv("DEV_MONGODB_URI", raising=False)
+    monkeypatch.setenv("MONGODB_URI", "mongodb://wrong.example")
+    path = tmp_path / ".cfg.toml"
+    path.write_text(
+        """
+[project]
+name = "test"
+
+[[collection]]
+name = "demo"
+id_field = "id"
+
+[env.dev]
+database = "mongo"
+uri = "env:DEV_MONGODB_URI"
+db = "cfgit-test"
+""",
+        encoding="utf-8",
+    )
+
+    project = load_config(path)
+
+    assert project.envs["dev"].uri == ""
diff --git a/tests/test_engine_safety.py b/tests/test_engine_safety.py
index 2ba7fa0..1d341ec 100644
--- a/tests/test_engine_safety.py
+++ b/tests/test_engine_safety.py
@@ -152,6 +152,22 @@ def test_single_record_valid_time_ref_resolves_date_syntax() -> None:
     assert resolved["doc"]["value"] == "old"
 
 
+def test_bare_numeric_ref_not_found_points_to_sequence_syntax() -> None:
+    coll = CollectionConfig(name="demo", id_field="id")
+    row = _history_row(
+        coll,
+        {"id": "alpha", "value": "old"},
+        seq=12,
+        valid_from=datetime(2026, 6, 1, tzinfo=timezone.utc),
+    )
+    engine, _adapter = _engine(collection=coll, history=[row], heads={("demo", "alpha"): row})
+
+    with pytest.raises(NoSuchConfig, match=r"sequence refs use @12"):
+        engine.resolve_ref(RecordRef("demo", "alpha"), "12")
+
+    assert engine.resolve_ref(RecordRef("demo", "alpha"), "@12")["seq"] == 12
+
+
 def test_empty_message_is_rejected_in_engine() -> None:
     engine, _adapter = _engine(records={("demo", "alpha"): {"id": "alpha", "value": 1}})
 
@@ -589,8 +605,14 @@ def query_history(
                 continue
             if record_id is not None and row["record_id"] != record_id:
                 continue
-            if ref is not None and ref.startswith("@") and row["seq"] != int(ref[1:]):
-                continue
+            if ref is not None:
+                if ref.startswith("@"):
+                    if row["seq"] != int(ref[1:]):
+                        continue
+                else:
+                    oid = ref.removeprefix("sha256:").removeprefix("#")
+                    if not str(row["oid"]).startswith(oid):
+                        continue
             if as_of_recorded is not None and row["recorded_at"] > as_of_recorded:
                 continue
             if as_of_valid is not None: