diff --git a/backend/apps/outputs/reap_ghost_runtimes.py b/backend/apps/outputs/reap_ghost_runtimes.py
index 6391aa1f..b053875a 100644
--- a/backend/apps/outputs/reap_ghost_runtimes.py
+++ b/backend/apps/outputs/reap_ghost_runtimes.py
@@ -56,13 +56,41 @@ def p_ppid_map() -> dict:
     return m
 
 
+@typechecked
+def p_cwd_map(needle: str) -> dict:
+    """pid -> cwd, for processes whose working directory sits under the workspace.
+
+    An app's backend is spawned as `python -u backend.py` with `cwd=<workspace>`, so the workspace
+    path appears NOWHERE in its argv: an argv-only scan is structurally blind to exactly the ghost
+    we most want dead. lsof is the only way to read another process's cwd on macOS. Best-effort by
+    design, since a machine that restricts lsof must still boot.
+    """
+    try:
+        out = subprocess.run(
+            ["lsof", "-a", "-d", "cwd", "-Fn"], capture_output=True, text=True, timeout=15
+        )
+    except Exception:
+        return {}
+    m = {}
+    pid = None
+    for raw in (out.stdout or "").splitlines():
+        if not raw:
+            continue
+        tag, val = raw[0], raw[1:]
+        if tag == "p" and val.isdigit():
+            pid = int(val)
+        elif tag == "n" and pid is not None and val.casefold().startswith(needle):
+            m[pid] = val
+    return m
+
+
 @typechecked
 def find_ghost_runtime_pids() -> List[int]:
     """PIDs of workspace processes that NO live backend owns.
 
-    Matched on the absolute workspace path, so an unrelated `npm run dev` elsewhere is never touched,
-    then filtered by walking each candidate's ancestry: if a live backend is anywhere above it, it is
-    someone's working app and is left alone.
+    Matched on the absolute workspace path (in argv OR as the process's working directory), so an
+    unrelated `npm run dev` elsewhere is never touched, then filtered by walking each candidate's
+    ancestry: if a live backend is anywhere above it, it is someone's working app and is left alone.
     """
     # Case-FOLDED needle. macOS's default filesystem is case-insensitive, so a process may report
     # `.../openswarm/...` while our resolved path is `.../OpenSwarm/...`: the same folder, but a
@@ -80,15 +108,17 @@ def find_ghost_runtime_pids() -> List[int]:
     # Boot relied on running before anything spawned; the 10-minute sweep gets no such alibi.
     if not owners or not parents:
         return []
-    ghosts: List[int] = []
+    by_cwd = p_cwd_map(needle)
+    candidates = dict.fromkeys(by_cwd)
     for line in (out.stdout or "").splitlines():
         line = line.strip()
         if needle not in line.casefold():
             continue
         head = line.split(None, 1)
-        if not head or not head[0].isdigit():
-            continue
-        pid = int(head[0])
+        if head and head[0].isdigit():
+            candidates[int(head[0])] = None
+    ghosts: List[int] = []
+    for pid in candidates:
         if pid == mine:
             continue
         cur, owned, broken = pid, False, False
diff --git a/backend/tests/test_reap_ghost_runtimes.py b/backend/tests/test_reap_ghost_runtimes.py
index 4def1293..f3f96f40 100644
--- a/backend/tests/test_reap_ghost_runtimes.py
+++ b/backend/tests/test_reap_ghost_runtimes.py
@@ -133,3 +133,31 @@ def test_ghost_matched_despite_path_case_difference(monkeypatch):
         stdout = f"50 python -m uvicorn backend.main:app\n700 bash {lower_ws}/ws-x/backend/run.sh\n"
     monkeypatch.setattr(rg.subprocess, "run", lambda *a, **k: P_Out())
     assert rg.find_ghost_runtime_pids() == [700], "a case-different path must still match the ghost"
+
+
+def test_an_orphan_is_found_by_its_CWD_when_argv_hides_the_path(monkeypatch):
+    """An app's backend runs as `python -u backend.py` with cwd=<workspace>, so the workspace path is
+    nowhere in its argv. An argv-only scan was structurally blind to exactly the ghost we most want
+    dead; found live on a packaged build where orphaned app backends survived every reap."""
+    from backend.apps.outputs import reap_ghost_runtimes as rg
+    ws = rg.os.path.abspath(rg.WORKSPACE_DIR)
+    monkeypatch.setattr(rg, "p_live_backend_pids", lambda: {50})
+    monkeypatch.setattr(rg, "p_ppid_map", lambda: {900: 1})
+    monkeypatch.setattr(rg, "p_cwd_map", lambda needle: {900: ws + "/app-7"})
+    class P_Out:
+        stdout = "50 python -m uvicorn backend.main:app\n900 python3 -u backend.py\n"
+    monkeypatch.setattr(rg.subprocess, "run", lambda *a, **k: P_Out())
+    assert rg.find_ghost_runtime_pids() == [900], "a cwd-only orphan must still be reaped"
+
+
+def test_a_cwd_orphan_owned_by_a_live_backend_is_spared(monkeypatch):
+    """The cwd path must obey the same ancestry rule: a working app is not a ghost."""
+    from backend.apps.outputs import reap_ghost_runtimes as rg
+    ws = rg.os.path.abspath(rg.WORKSPACE_DIR)
+    monkeypatch.setattr(rg, "p_live_backend_pids", lambda: {50})
+    monkeypatch.setattr(rg, "p_ppid_map", lambda: {900: 50, 50: 1})
+    monkeypatch.setattr(rg, "p_cwd_map", lambda needle: {900: ws + "/app-7"})
+    class P_Out:
+        stdout = "50 python -m uvicorn backend.main:app\n900 python3 -u backend.py\n"
+    monkeypatch.setattr(rg.subprocess, "run", lambda *a, **k: P_Out())
+    assert rg.find_ghost_runtime_pids() == [], "a live backend's own app runtime must never be killed"