PR #28977: fix: preserve message timestamps across fork/compress/branch

• Repository: NousResearch/hermes-agent
• Author: zccyman
• State: closed | merged: False
• Link: https://github.com/NousResearch/hermes-agent/pull/28977

Description (problem / solution / changelog)

Summary

Fixes #28841 — messages.timestamp is always set to DB write-time (time.time()), silently discarding original timestamps when sessions are forked, compressed, or branched via /retry, /undo, or /compress.

Root Cause

Two sites in hermes_state.py:

1. append_message() (L1492): hardcodes time.time() — no way to pass an explicit timestamp.
2. replace_messages() (L1537/1575): sets now_ts = time.time() once and stamps every row with that single value, ignoring any existing msg["timestamp"].

Fix

hermes_state.py (+3/-1)

• append_message(): add optional timestamp: float = None parameter. Uses explicit value when provided, falls back to time.time().
• replace_messages(): per-message msg.get("timestamp", now_ts) instead of uniform now_ts.

Caller updates (+4 lines)

Four callers that copy existing messages during fork/branch now forward timestamp=msg.get("timestamp"):

• run_agent.py — _flush_messages_to_session_db
• cli.py — /branch handler
• gateway/run.py — gateway branch handler
• tui_gateway/server.py — TUI branch handler

Two remaining callers (gateway/session.py, gateway/mirror.py) handle live messages where the default time.time() is correct — no change needed.

Testing

6 new tests in tests/test_hermes_state.py:

• test_append_message_explicit_timestamp — explicit timestamp stored correctly
• test_append_message_default_timestamp — default falls back to time.time()
• test_replace_messages_preserves_timestamps — per-message timestamps retained
• test_replace_messages_falls_back_to_now — missing timestamps default to now_ts
• test_replace_messages_mixed_timestamps — explicit and default in same batch
• test_fork_preserves_timestamps — end-to-end fork scenario

All 219 tests in test_hermes_state.py pass (6 new + 213 existing, zero regressions).

Backward Compatibility

Fully backward compatible:

• timestamp parameter defaults to None → existing callers unchanged
• replace_messages() falls back to now_ts for messages without timestamps
• No schema migration needed — the timestamp column already exists

Co-Authored-By: zccyman [email protected]

Changed files

• .dev-workflow/code-graph.db (added, +0/-0)
• .dev-workflow/experiences.jsonl (added, +1/-0)
• analyzed_issues.json (added, +62/-0)
• cli.py (modified, +1/-0)
• gateway/run.py (modified, +1/-0)
• hermes_state.py (modified, +3/-2)
• run_agent.py (modified, +1/-0)
• tests/test_hermes_state.py (modified, +106/-0)
• tui_gateway/server.py (modified, +1/-0)