diff --git a/skills/work-plan/lib/drift.py b/skills/work-plan/lib/drift.py
index 456e5b8..9c4d42b 100644
--- a/skills/work-plan/lib/drift.py
+++ b/skills/work-plan/lib/drift.py
@@ -23,8 +23,13 @@ def detect_drift(body: str, github_issues: list[dict]) -> list[dict]:
                 continue
             gh_state = state_by_num[num]
             looks_closed = any(k in body_status for k in ("✅", "shipped", "merged", "closed"))
-            looks_open = "🔲" in body_status or "open" in body_status
 
+            # Asymmetric by design: CLOSED is terminal, so a closed issue whose
+            # row doesn't explicitly read closed (open marker, ambiguous, or empty)
+            # is drift. OPEN is not terminal — an open issue legitimately sits in
+            # many states (in-progress, blocked, todo), so only an explicit closed
+            # marker contradicts it. A broad open-side check (`not looks_open`)
+            # would false-positive every in-progress row, which is why we don't.
             if gh_state == "CLOSED" and not looks_closed:
                 drift.append({"issue": num, "body_status": body_status, "github_state": "CLOSED"})
             elif gh_state == "OPEN" and looks_closed:
diff --git a/skills/work-plan/tests/test_drift.py b/skills/work-plan/tests/test_drift.py
index d117faa..68293be 100644
--- a/skills/work-plan/tests/test_drift.py
+++ b/skills/work-plan/tests/test_drift.py
@@ -33,6 +33,38 @@ def test_drift_when_open_in_md_closed_in_github(self):
     def test_no_table_returns_empty(self):
         self.assertEqual(detect_drift("# No table\n", [{"number": 1, "state": "CLOSED"}]), [])
 
+    # --- OPEN-side + ambiguous-body cases: pin the *intentional asymmetry* ----
+    # CLOSED is terminal → broad check (anything not-closed drifts). OPEN is not
+    # terminal → narrow check (only an explicit closed marker drifts). These
+    # guard against someone "restoring symmetry" with a `not looks_open` open-side
+    # check, which would false-positive every in-progress row.
+
+    def _body(self, status: str) -> str:
+        return ("| # | Title | Status |\n"
+                "|---|---|---|\n"
+                f"| #1 | foo | {status} |\n")
+
+    def test_drift_when_closed_in_md_open_in_github(self):
+        # OPEN-side condition (was untested): body says shipped, GitHub reopened it.
+        drift = detect_drift(self._body("✅ Shipped"), [{"number": 1, "state": "OPEN"}])
+        self.assertEqual(len(drift), 1)
+        self.assertEqual(drift[0]["github_state"], "OPEN")
+
+    def test_no_drift_when_open_in_md_open_in_github(self):
+        self.assertEqual(detect_drift(self._body("🔲 Open"), [{"number": 1, "state": "OPEN"}]), [])
+
+    def test_open_with_ambiguous_status_is_NOT_drift(self):
+        # The deliberate narrow OPEN-side: an in-progress row must not be flagged.
+        self.assertEqual(
+            detect_drift(self._body("🚧 In progress"), [{"number": 1, "state": "OPEN"}]), [])
+
+    def test_closed_with_ambiguous_status_IS_drift(self):
+        # The deliberate broad CLOSED-side: a closed issue whose row doesn't read
+        # closed (here: ambiguous) is drift.
+        drift = detect_drift(self._body("🚧 In progress"), [{"number": 1, "state": "CLOSED"}])
+        self.assertEqual(len(drift), 1)
+        self.assertEqual(drift[0]["github_state"], "CLOSED")
+
 
 if __name__ == "__main__":
     unittest.main()