diff --git a/hermes_cli/kanban_db.py b/hermes_cli/kanban_db.py
index c89e697c98d29..6dceaaf678eb0 100644
--- a/hermes_cli/kanban_db.py
+++ b/hermes_cli/kanban_db.py
@@ -1473,12 +1473,22 @@ def write_txn(conn: sqlite3.Connection):
     Use for any multi-statement write (creating a task + link, claiming a
     task + recording an event, etc.).  A claim CAS inside this context is
     atomic -- at most one concurrent writer can succeed.
+
+    The explicit ROLLBACK on exception is wrapped in try/except so that
+    a SQLite auto-rollback (which leaves no active transaction) does not
+    shadow the original exception with a spurious rollback error.
     """
     conn.execute("BEGIN IMMEDIATE")
     try:
         yield conn
     except Exception:
-        conn.execute("ROLLBACK")
+        try:
+            conn.execute("ROLLBACK")
+        except sqlite3.OperationalError:
+            # SQLite has already auto-rolled-back the transaction (typical
+            # under EIO, lock contention, or corruption). Nothing to undo;
+            # do not let this secondary failure shadow the real one.
+            pass
         raise
     else:
         conn.execute("COMMIT")
diff --git a/scripts/release.py b/scripts/release.py
index dc7d6c4fe5e21..f10cff2c0705c 100755
--- a/scripts/release.py
+++ b/scripts/release.py
@@ -1284,6 +1284,7 @@
     "erik.engervall@gmail.com": "erikengervall",  # PR #28774 (firecrawl integration tag)
     "egilewski@egilewski.com": "egilewski",  # PR #30432 (MEDIA path traversal fix, GHSA-jmf9-9729-7pp8)
     "edison@mcclean.codes": "McClean-Edison",  # PR #29817 (register_auxiliary_task plugin API)
+    "steveonjava@gmail.com": "steveonjava",  # PR #31310 (write_txn rollback guard)
     "zhangsamuel12@gmail.com": "SamuelZ12",  # PR #7480 (show recap after in-session resume)
     "490408354@qq.com": "daizhonggeng",  # PR #9020 (numbered /resume selection)
 }
diff --git a/tests/hermes_cli/test_kanban_db.py b/tests/hermes_cli/test_kanban_db.py
index 883cf8f4d5db0..9a207ff8cb0cb 100644
--- a/tests/hermes_cli/test_kanban_db.py
+++ b/tests/hermes_cli/test_kanban_db.py
@@ -3339,3 +3339,61 @@ def test_maybe_emit_scratch_tip_skips_non_scratch_workspaces(kanban_home, caplog
             ).fetchall()
             assert "tip_scratch_workspace" not in [e["kind"] for e in events]
 
+
+# write_txn — rollback handler must not mask the original exception
+# ---------------------------------------------------------------------------
+
+
+def test_write_txn_preserves_original_exception_when_rollback_fails(kanban_home):
+    """When a write inside write_txn raises an OperationalError that SQLite
+    has already auto-rolled-back (e.g. ``disk I/O error``,
+    ``database is locked``, ``database disk image is malformed``), the
+    explicit ROLLBACK in ``write_txn.__exit__`` itself raises
+    ``cannot rollback - no transaction is active``. The original cause
+    must NOT be masked by the secondary rollback failure — operators rely
+    on the original cause to diagnose the underlying issue.
+    """
+
+    class FailingConnWrapper:
+        """Delegate to a real connection, simulating an EIO during an INSERT
+        that SQLite has already auto-rolled-back."""
+
+        def __init__(self, real):
+            self._real = real
+            self._fail_armed = True
+
+        def execute(self, sql, *args, **kwargs):
+            if (
+                self._fail_armed
+                and sql.lstrip().upper().startswith("INSERT")
+                and "task_events" in sql.lower()
+            ):
+                self._fail_armed = False  # one-shot
+                # Simulate SQLite auto-rolling back the transaction by
+                # issuing a real ROLLBACK now. After this, BEGIN IMMEDIATE
+                # is no longer active and an explicit ROLLBACK would error.
+                try:
+                    self._real.execute("ROLLBACK")
+                except sqlite3.OperationalError:
+                    pass
+                raise sqlite3.OperationalError("disk I/O error")
+            return self._real.execute(sql, *args, **kwargs)
+
+        def __getattr__(self, name):
+            return getattr(self._real, name)
+
+    with kb.connect() as conn:
+        wrapper = FailingConnWrapper(conn)
+        with pytest.raises(sqlite3.OperationalError) as excinfo:
+            with kb.write_txn(wrapper):
+                kb._append_event(wrapper, "t_bogus", "promoted", None)
+
+    msg = str(excinfo.value)
+    assert "disk I/O error" in msg, (
+        f"write_txn masked the original exception with rollback failure; "
+        f"got {msg!r} (expected to contain 'disk I/O error')"
+    )
+    assert "cannot rollback" not in msg, (
+        f"write_txn surfaced the rollback failure instead of the original "
+        f"OperationalError; got {msg!r}"
+    )