# NousResearch/hermes-agent · Thread safety fixes for session and message counts ## Open now - Nothing open on GitHub. Multiple issues and pull requests addressing missing thread locks in session_count() and message_count() methods, with related concurrent subagent thread safety fixes. The group centers on a specific thread-safety bug and its proposed fixes. ## TL;DR - 6 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 4 PR(s) closed without merging. - A fix was merged to main in PR #2466. Verify it addresses your case. - **Recommended:** read PR #2466 (and any competing PRs below) before filing. Confirm the merged change covers your symptom. ## Maintainer resolution verdict - Internal-tracker verdict over this cluster's issue members: `unresolved`. This is distinct from the fix status above. Weigh it yourself. ## How this cluster was grouped - Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference. - Pairwise link density `0.33`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked. ## Closed / duplicate issues - #2130: Bug: session_count() and message_count() missing thread lock ## Prior & competing PRs - **#2251: fix(state): add missing thread lock to session_count() and message_count()**. closed without merge · fix tier `suggested` - maintainer direction: category `uncategorized`; implication `needs_llm` - _suggested-tier fix detail withheld; re-request with `?tier=all` to include it._ - **#2466: fix: batch of 5 small contributor fixes — PortAudio, SafeWriter, IMAP, thread lock, prefill**. merged to main · fix tier `verified` - maintainer direction: category `merged`; implication `superseded` - files: `gateway/platforms/email.py`, `hermes_state.py`, `run_agent.py`, `tools/voice_mode.py` - fix hunks: - `gateway/platforms/email.py` ```diff @@ -230,7 +230,7 @@ async def connect(self) -> bool: # Mark all existing messages as seen so we only process new ones imap.select("INBOX") status, data = imap.uid("search", None, "ALL") - if status == "OK" and data[0]: + if status == "OK" and data and data[0]: for uid in data[0].split(): self._seen_uids.add(uid) imap.logout() ``` ```diff @@ -295,7 +295,7 @@ def _fetch_new_messages(self) -> List[Dict[str, Any]]: imap.select("INBOX") status, data = imap.uid("search", None, "UNSEEN") - if status != "OK" or not data[0]: + if status != "OK" or not data or not data[0]: imap.logout() return results ``` - `hermes_state.py` ```diff @@ -855,23 +855,25 @@ def search_sessions( def session_count(self, source: str = None) -> int: """Count sessions, optionally filtered by source.""" - if source: - cursor = self._conn.execute( - "SELECT COUNT(*) FROM sessions WHERE source = ?", (source,) - ) - else: - cursor = self._conn.execute("SELECT COUNT(*) FROM sessions") - return cursor.fetchone()[0] + with self._lock: + if source: + cursor = self._conn.execute( + "SELECT COUNT(*) FROM sessions WHERE source = ?", (source,) + ) + else: + cursor = self._conn.execute("SELECT COUNT(*) FROM sessions") + return cursor.fetchone()[0] def message_count(self, session_id: str = None) -> int: """Count messages, optionally for a specific session.""" - if session_id: - cursor = self._conn.execute( - "SELECT COUNT(*) FROM messages WHERE session_id = ?", (session_id,) - ) - else: - cursor = self._conn.execute("SELECT COUNT(*) FROM messages") - return cursor.fetchone()[0] + with self._lock: + if session_id: + cursor = self._conn.execute( + "SELECT COUNT(*) FROM messages WHERE session_id = ?", (session_id,) + ) + else: + cursor = self._conn.execute("SELECT COUNT(*) FROM messages") + return cursor.fetchone()[0] # ========================================================================= # Export and cleanup ``` - `run_agent.py` ```diff @@ -108,7 +108,7 @@ class _SafeWriter: - """Transparent stdio wrapper that catches OSError from broken pipes. + """Transparent stdio wrapper that catches OSError/ValueError from broken pipes. When hermes-agent runs as a systemd service, Docker container, or headless daemon, the stdout/stderr pipe can become unavailable (idle timeout, buffer ``` ```diff @@ -117,8 +117,13 @@ class _SafeWriter: run_conversation() — especially via double-fault when an except handler also tries to print. + Additionally, when subagents run in ThreadPoolExecutor threads, the shared + stdout handle can close between thread teardown and cleanup, raising + ``ValueError: I/O operation on closed file`` instead of OSError. + This wrapper delegates all writes to the underlying stream and silently - catches OSError. It is transparent when the wrapped stream is healthy. + catches both OSError and ValueError. It is transparent when the wrapped + stream is healthy. """ __slots__ = ("_inner",) ``` ```diff @@ -129,13 +134,13 @@ def __init__(self, inner): def write(self, data): try: return self._inner.write(data) - except OSError: + except (OSError, ValueError): return len(data) if isinstance(data, str) else 0 def flush(self): try: self._inner.flush() - except OSError: + except (OSError, ValueError): pass def fileno(self): ``` ```diff @@ -144,7 +149,7 @@ def fileno(self): def isatty(self): try: return self._inner.isatty() - except OSError: + except (OSError, ValueError): return False def __getattr__(self, name): ``` ```diff @@ -2438,7 +2443,18 @@ def _sanitize_api_messages(messages: List[Dict[str, Any]]) -> List[Dict[str, Any "Pre-call sanitizer: added %d stub tool result(s)", len(missing_results), ) - + # 3. Strip trailing empty assistant messages to prevent prefill rejection. + # These can leak from Responses API reasoning-only turns (Codex/MiniMax) + # where an empty assistant message is required by the Responses API but + # must NOT be sent to Chat Completions or Anthropic Messages API providers. + while ( + messages + and messages[-1].get("role") == "assistant" + and not (messages[-1].get("content") or "").strip() + and not messages[-1].get("tool_calls") + ): + logger.debug("Pre-call sanitizer: removed trailing empty assistant message") + messages = messages[:-1] return messages @staticmethod ``` - `tools/voice_mode.py` ```diff @@ -81,8 +81,15 @@ def detect_audio_environment() -> dict: warnings.append("No audio input/output devices detected") except Exception: warnings.append("Audio subsystem error (PortAudio cannot query devices)") - except (ImportError, OSError): + except ImportError: warnings.append("Audio libraries not installed (pip install sounddevice numpy)") + except OSError: + warnings.append( + "PortAudio system library not found -- install it first:\n" + " Linux: sudo apt-get install libportaudio2\n" + " macOS: brew install portaudio\n" + "Then retry /voice on." + ) return { "available": len(warnings) == 0, ``` - **#2131: fix(state): add missing thread lock to session_count() and message_count()**. closed without merge - maintainer direction: category `duplicate_of`; implication `duplicate` - **#2133: fix(state): add thread lock to session_count() and message_count()**. closed without merge - maintainer direction: category `duplicate_of`; implication `duplicate` - **#2288: fix(state): add missing thread lock to session_count() and message_count()**. closed without merge - maintainer direction: category `merged_via`; implication `superseded`; refs `#2466` ## Fix status - Merged to main in PR #2466 (cited above). No release data is tracked. Verify downstream. - Fix last verified (merged) `2026-03-22`. This confirmation is old and may be out of date (a revert/reopen would not have invalidated it here); re-verify. - Subsystem: `agent`