diff --git a/hermes_cli/oneshot.py b/hermes_cli/oneshot.py
index 1dd24951c..f66d71c62 100644
--- a/hermes_cli/oneshot.py
+++ b/hermes_cli/oneshot.py
@@ -174,28 +174,51 @@ def run_oneshot(
     # Redirect stderr AND stdout to devnull for the entire call tree.
     # We'll print the final response to the real stdout at the end.
     real_stdout = sys.stdout
+    real_stderr = sys.stderr
     devnull = open(os.devnull, "w", encoding="utf-8")
 
+    response: Optional[str] = None
+    failure: BaseException | None = None
     try:
         with redirect_stdout(devnull), redirect_stderr(devnull):
-            response = _run_agent(
-                prompt,
-                model=model,
-                provider=provider,
-                toolsets=explicit_toolsets,
-                use_config_toolsets=use_config_toolsets,
-            )
+            try:
+                response = _run_agent(
+                    prompt,
+                    model=model,
+                    provider=provider,
+                    toolsets=explicit_toolsets,
+                    use_config_toolsets=use_config_toolsets,
+                )
+            except BaseException as exc:  # noqa: BLE001
+                # Capture anything that escapes the agent (including OSError
+                # from prompt_toolkit/Vt100 when stdout is a non-TTY pipe,
+                # KeyboardInterrupt, SystemExit, etc.) so we can surface it on
+                # the real stderr instead of crashing past the redirect with a
+                # traceback that the caller never sees. A silent exit in a
+                # cron / SSH / subprocess context is the worst failure mode.
+                # See #30623.
+                failure = exc
     finally:
         try:
             devnull.close()
         except Exception:
             pass
 
-    if not (response or "").strip():
-        sys.stderr.write("hermes -z: no final response was produced; treating the run as failed.\n")
-        sys.stderr.flush()
+    if failure is not None:
+        # Re-raise control-flow exceptions so the parent handles them as usual
+        # (Ctrl-C / explicit sys.exit() inside the agent).
+        if isinstance(failure, (KeyboardInterrupt, SystemExit)):
+            raise failure
+        real_stderr.write(f"hermes -z: agent failed: {failure}\n")
+        real_stderr.flush()
         return 1
 
+    if not (response or "").strip():
+        real_stderr.write("hermes -z: no final response was produced; treating the run as failed.\n")
+        real_stderr.flush()
+        return 1
+
+    assert response is not None  # narrowed by the empty-response guard above
     real_stdout.write(response)
     if not response.endswith("\n"):
         real_stdout.write("\n")
diff --git a/scripts/release.py b/scripts/release.py
index a5f8fcb10..30d0d84d6 100755
--- a/scripts/release.py
+++ b/scripts/release.py
@@ -658,6 +658,7 @@ AUTHOR_MAP = {
     "incharge.automation@gmail.com": "inchargeautomation-lab",
     "danielrpike9@gmail.com": "Bartok9",
     "96944678+ymylive@users.noreply.github.com": "sweetcornna",
+    "laflamme@illinoisalumni.org": "briancl2",
     "skozyuk@cruxexperts.com": "CruxExperts",
     "154585401+LeonSGP43@users.noreply.github.com": "LeonSGP43",
     "12250313+Kailigithub@users.noreply.github.com": "Kailigithub",
diff --git a/tests/hermes_cli/test_tui_resume_flow.py b/tests/hermes_cli/test_tui_resume_flow.py
index ef002c9af..d15d67c00 100644
--- a/tests/hermes_cli/test_tui_resume_flow.py
+++ b/tests/hermes_cli/test_tui_resume_flow.py
@@ -662,6 +662,36 @@ def test_oneshot_prints_nonempty_final_response(monkeypatch, capsys):
     assert captured.err == ""
 
 
+def test_oneshot_fails_closed_on_agent_exception(monkeypatch, capsys):
+    _stub_plugin_discovery(monkeypatch)
+    import hermes_cli.oneshot as oneshot_mod
+
+    def _boom(*_args, **_kwargs):
+        raise OSError("not a TTY")
+
+    monkeypatch.setattr(oneshot_mod, "_run_agent", _boom)
+
+    assert oneshot_mod.run_oneshot("hello") == 1
+    captured = capsys.readouterr()
+    assert captured.out == ""
+    assert "agent failed" in captured.err
+    assert "not a TTY" in captured.err
+
+
+def test_oneshot_reraises_keyboard_interrupt(monkeypatch):
+    _stub_plugin_discovery(monkeypatch)
+    import hermes_cli.oneshot as oneshot_mod
+    import pytest as _pytest
+
+    def _interrupt(*_args, **_kwargs):
+        raise KeyboardInterrupt
+
+    monkeypatch.setattr(oneshot_mod, "_run_agent", _interrupt)
+
+    with _pytest.raises(KeyboardInterrupt):
+        oneshot_mod.run_oneshot("hello")
+
+
 def test_oneshot_filters_invalid_toolsets_before_redirect(monkeypatch, capsys):
     _stub_plugin_discovery(monkeypatch)
     from hermes_cli.oneshot import _validate_explicit_toolsets