fix(cli): handle EOFError in sessions delete/prune confirmation prompts (#3101)

sessions delete and prune call input() for confirmation without
catching EOFError. When stdin isn't a TTY (piped input, CI/CD, cron),
input() throws EOFError and the command crashes.

Extract a _confirm_prompt() helper that handles EOFError and
KeyboardInterrupt, defaulting to cancel. Both call sites now use it.

Salvaged from PR #2622 by dieutx (improved from duplicated try/except
to shared helper). Closes #2565.

hermes_cli/main.py

@@ -3844,6 +3844,13 @@ For more help on a command:
     sessions_browse.add_argument("--source", help="Filter by source (cli, telegram, discord, etc.)")
     sessions_browse.add_argument("--limit", type=int, default=50, help="Max sessions to load (default: 50)")
 
+    def _confirm_prompt(prompt: str) -> bool:
+        """Prompt for y/N confirmation, safe against non-TTY environments."""
+        try:
+            return input(prompt).strip().lower() in ("y", "yes")
+        except (EOFError, KeyboardInterrupt):
+            return False
+
     def cmd_sessions(args):
         import json as _json
         try:
@@ -3904,8 +3911,7 @@ For more help on a command:
                 print(f"Session '{args.session_id}' not found.")
                 return
             if not args.yes:
-                confirm = input(f"Delete session '{resolved_session_id}' and all its messages? [y/N] ")
-                if confirm.lower() not in ("y", "yes"):
+                if not _confirm_prompt(f"Delete session '{resolved_session_id}' and all its messages? [y/N] "):
                     print("Cancelled.")
                     return
             if db.delete_session(resolved_session_id):
@@ -3917,8 +3923,7 @@ For more help on a command:
             days = args.older_than
             source_msg = f" from '{args.source}'" if args.source else ""
             if not args.yes:
-                confirm = input(f"Delete all ended sessions older than {days} days{source_msg}? [y/N] ")
-                if confirm.lower() not in ("y", "yes"):
+                if not _confirm_prompt(f"Delete all ended sessions older than {days} days{source_msg}? [y/N] "):
                     print("Cancelled.")
                     return
             count = db.prune_sessions(older_than_days=days, source=args.source)

tests/hermes_cli/test_sessions_delete.py

@@ -62,3 +62,56 @@ def test_sessions_delete_reports_not_found_when_prefix_is_unknown(monkeypatch, c
 
     output = capsys.readouterr().out
     assert "Session 'missing-prefix' not found." in output
+
+
+def test_sessions_delete_handles_eoferror_on_confirm(monkeypatch, capsys):
+    """sessions delete should not crash when stdin is closed (non-TTY)."""
+    import hermes_cli.main as main_mod
+    import hermes_state
+
+    class FakeDB:
+        def resolve_session_id(self, session_id):
+            return "20260315_092437_c9a6ff"
+
+        def delete_session(self, session_id):
+            raise AssertionError("delete_session should not be called when cancelled")
+
+        def close(self):
+            pass
+
+    monkeypatch.setattr(hermes_state, "SessionDB", lambda: FakeDB())
+    monkeypatch.setattr(
+        sys, "argv",
+        ["hermes", "sessions", "delete", "20260315_092437_c9a6"],
+    )
+    monkeypatch.setattr("builtins.input", lambda _prompt="": (_ for _ in ()).throw(EOFError))
+
+    main_mod.main()
+
+    output = capsys.readouterr().out
+    assert "Cancelled" in output
+
+
+def test_sessions_prune_handles_eoferror_on_confirm(monkeypatch, capsys):
+    """sessions prune should not crash when stdin is closed (non-TTY)."""
+    import hermes_cli.main as main_mod
+    import hermes_state
+
+    class FakeDB:
+        def prune_sessions(self, **kwargs):
+            raise AssertionError("prune_sessions should not be called when cancelled")
+
+        def close(self):
+            pass
+
+    monkeypatch.setattr(hermes_state, "SessionDB", lambda: FakeDB())
+    monkeypatch.setattr(
+        sys, "argv",
+        ["hermes", "sessions", "prune"],
+    )
+    monkeypatch.setattr("builtins.input", lambda _prompt="": (_ for _ in ()).throw(EOFError))
+
+    main_mod.main()
+
+    output = capsys.readouterr().out
+    assert "Cancelled" in output