# NousResearch/hermes-agent · TUI compression and live session identity preservation

## Open now

- Nothing open on GitHub.

The members all concern the TUI's auto-compression affecting live session identity. One is an issue describing session lineage forking and messages mixing across sessions, and the others are pull requests (one referencing #49041) titled as fixes to preserve session identity across compression. Only the titles are available, so the details are not confirmed.

## TL;DR

- 3 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 1 PR(s) closed without merging.
- A fix was merged to main in PR #51509. Verify it addresses your case.
- **Recommended:** read PR #51509 (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: `resolved` · deciding PR(s): `pr-51509`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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 `0.67`: 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

- #49041: TUI auto-compression can fork live session lineage and mix messages across sessions

## Prior & competing PRs

- **#51509: fix(tui): preserve live session identity across compression (#49041)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `hermes_cli/active_sessions.py`, `tests/hermes_cli/test_active_sessions.py`, `tests/tui_gateway/test_protocol.py`, `tui_gateway/server.py`
  - fix hunks:
  - `hermes_cli/active_sessions.py`

    ```diff
    @@ -78,7 +78,7 @@ def active_session_limit_message(active_count: int, max_sessions: int) -> str:
     
     
     def _state_dir() -> Path:
    -    return get_hermes_home() / "runtime"
    +    return Path(get_hermes_home()) / "runtime"
     
     
     def _state_path() -> Path:
    ```

    ```diff
    @@ -311,6 +311,43 @@ def release_active_session(lease: ActiveSessionLease) -> None:
             lease.released = True
     
     
    +def transfer_active_session(
    +    lease: ActiveSessionLease,
    +    *,
    +    session_id: str,
    +    metadata: Optional[dict[str, Any]] = None,
    +) -> bool:
    +    """Move an existing lease to a new session id without dropping the slot."""
    +    new_session_id = str(session_id or "")
    +    if not new_session_id:
    +        return False
    +    if lease.released:
    +        return False
    +    if not lease.enabled:
    +        lease.session_id = new_session_id
    +        return True
    +
    +    state_path = _state_path()
    +    with _FileLock(_lock_path()):
    +        entries = _prune_dead(_read_entries(state_path))
    +        updated = False
    +        for entry in entries:
    +            if str(entry.get("lease_id") or "") != lease.lease_id:
    +                continue
    +            entry["session_id"] = new_session_id
    +            entry["updated_at"] = time.time()
    +            if metadata:
    +                entry["metadata"] = {
    +                    str(k): v for k, v in metadata.items() if isinstance(k, str)
    +                }
    +            updated = True
    +            break
    +        if updated:
    +            _write_entries(state_path, entries)
    +            lease.session_id = new_session_id
    +        return updated
    +
    +
     def active_session_registry_snapshot() -> list[dict[str, Any]]:
         """Return the pruned active-session registry for diagnostics/tests."""
         state_path = _state_path()
    ```
  - `tests/hermes_cli/test_active_sessions.py`

    ```diff
    @@ -113,6 +113,33 @@ def test_active_session_registry_prunes_dead_pids(tmp_path, monkeypatch):
         lease.release()
     
     
    +def test_transfer_active_session_reanchors_existing_lease(tmp_path, monkeypatch):
    +    home = tmp_path / ".hermes"
    +    monkeypatch.setenv("HERMES_HOME", str(home))
    +
    +    lease, message = active_sessions.try_acquire_active_session(
    +        session_id="session-old",
    +        surface="tui",
    +        config={"max_concurrent_sessions": 1},
    +        metadata={"live_session_id": "ui-1"},
    +    )
    +
    +    assert message is None
    +    assert lease is not None
    +    assert active_sessions.transfer_active_session(
    +        lease,
    +        session_id="session-new",
    +        metadata={"live_session_id": "ui-1"},
    +    )
    +
    +    snapshot = active_sessions.active_session_registry_snapshot()
    +    assert lease.session_id == "session-new"
    +    assert len(snapshot) == 1
    +    assert snapshot[0]["session_id"] == "session-new"
    +    assert snapshot[0]["metadata"] == {"live_session_id": "ui-1"}
    +    lease.release()
    +
    +
     def test_pid_alive_uses_safe_pid_exists_without_signalling(monkeypatch):
         checked: list[int] = []
     
    ```
  - `tests/tui_gateway/test_protocol.py`

    ```diff
    @@ -734,6 +734,100 @@ def resume_second():
         assert all(sid == winner for sid in server._sessions)
     
     
    +def test_session_resume_reuses_live_agent_after_compression_rotation(server, monkeypatch):
    +    """Resume must match the live agent's current session_id, not stale session_key."""
    +
    +    target = "20260409_020202_child"
    +    stale_parent = "20260409_010101_parent"
    +    sid = "live-rotated"
    +    server._sessions[sid] = {
    +        "agent": types.SimpleNamespace(model="test/model", session_id=target),
    +        "created_at": 123.0,
    +        "display_history_prefix": [],
    +        "history": [{"role": "assistant", "content": "live child"}],
    +        "history_lock": threading.RLock(),
    +        "last_active": 123.0,
    +        "running": False,
    +        "session_key": stale_parent,
    +        "transport": server._stdio_transport,
    +    }
    +
    +    class _DB:
    +        def get_session(self, _sid):
    +            return {"id": target}
    +
    +        def get_session_by_title(self, _title):
    +            return None
    +
    +        def resolve_resume_session_id(self, _target):
    +            return target
    +
    +    monkeypatch.setattr(server, "_get_db", lambda: _DB())
    +    monkeypatch.setattr(server, "_emit", lambda *_args, **_kwargs: None)
    +    monkeypatch.setattr(
    +        server,
    +        "_session_info",
    +        lambda _agent, _session=None: {"model": "test/model"},
    +    )
    +
    +    result = server.handle_request(
    +        {
    +            "id": "r1",
    +            "method": "session.resume",
    +            "params": {"session_id": target, "cols": 100},
    +        }
    +    )
    +
    +    assert "error" not in result
    +    assert result["result"]["session_id"] == sid
    +    assert result["result"]["session_key"] == target
    +    assert len(server._sessions) == 1
    +
    +
    +def test_sync_session_key_after_compress_reanchors_active_session_lease(
    +    server, monkeypatch, tmp_path
    +):
    +    home = tmp_path / ".hermes"
    +    monkeypatch.setenv("HERMES_HOME", str(home))
    +
    +    from hermes_cli.active_sessions import (
    +        active_session_registry_snapshot,
    +        try_acquire_active_session,
    +    )
    +
    +    lease, message = try_acquire_active_session(
    +        session_id="session-old",
    +        surface="tui",
    +        config={"max_concurrent_sessions": 1},
    +        metadata={"live_session_id": "ui-1"},
    +    )
    +    assert message is None
    +    assert lease is not None
    +
    +    session = {
    +        "active_session_lease": lease,
    +        "agent": types.SimpleNamespace(session_id="session-new"),
    +        "session_key": "session-old",
    +    }
    +    fake_approval = types.SimpleNamespace(
    +        disable_session_yolo=lambda *_args, **_kwargs: None,
    +        enable_session_yolo=lambda *_args, **_kwargs: None,
    +        is_session_yolo_enabled=lambda *_args, **_kwargs: False,
    +        register_gateway_notify=lambda *_args, **_kwargs: None,
    +        unregister_gateway_notify=lambda *_args, **_kwargs: None,
    +    )
    +    monkeypatch.setattr(server, "_restart_slash_worker", lambda *_args, **_kwargs: None)
    +
    +    with patch.dict(sys.modules, {"tools.approval": fake_approval}):
    +        server._sync_session_key_after_compress("ui-1", session)
    +
    +    snapshot = active_session_registry_snapshot()
    +    assert session["session_key"] == "session-new"
    +    assert lease.session_id == "session-new"
    +    assert [entry["session_id"] for entry in snapshot] == ["session-new"]
    +    lease.release()
    +
    +
     def test_session_resume_live_payload_uses_current_history_with_ancestors(server, monkeypatch):
         """Live resume should not reuse a stale ancestor-inclusive snapshot."""
     
    ```
  - `tui_gateway/server.py`

    ```diff
    @@ -381,6 +381,59 @@ def _release_active_session_slot(session: dict | None) -> None:
             logger.debug("Failed to release active session slot", exc_info=True)
     
     
    +def _transfer_active_session_slot(
    +    sid: str,
    +    session: dict,
    +    *,
    +    new_session_id: str,
    +) -> bool:
    +    if not new_session_id:
    +        return False
    +    lease = session.get("active_session_lease")
    +    if lease is None:
    +        return True
    +    try:
    +        from hermes_cli.active_sessions import transfer_active_session
    +
    +        if transfer_active_session(
    +            lease,
    +            session_id=new_session_id,
    +            metadata={"live_session_id": sid},
    +        ):
    +            return True
    +    except Exception:
    +        logger.debug("Failed to transfer active session slot", exc_info=True)
    +
    +    # Fallback: the in-place transfer could not move the lease (entry pruned /
    +    # pid-check transiently failed). Reserve the new slot BEFORE releasing the
    +    # old one, so a concurrent gateway at the session cap cannot grab the freed
    +    # slot in a release-then-reacquire window and leave this session with no
    +    # lease at all (#49041 review). If the reserve fails, KEEP the old lease.
    +    new_lease, limit_message = _claim_active_session_slot(
    +        new_session_id,
    +        live_session_id=sid,
    +    )
    +    if new_lease is not None:
    +        old_lease = session.pop("active_session_lease", None)
    +        if old_lease is not None:
    +            try:
    +                old_lease.release()
    +            except Exception:
    +                logger.debug("Failed to release stale active session slot", exc_info=True)
    +        session["active_session_lease"] = new_lease
    +        return True
    +    # Reserve failed — retain the existing lease rather than dropping it.
    +    if limit_message:
    +        logger.warning(
    +            "Compression session lease re-anchor failed (kept old lease): "
    +            "sid=%s new_session_id=%s reason=%s",
    +            sid,
    +            new_session_id,
    +            limit_message,
    +        )
    +    return False
    +
    +
     def _finalize_session(session: dict | None, end_reason: str = "tui_close") -> None:
         """Best-effort finalize hook + memory commit for a session.
     
    ```

    ```diff
    @@ -2543,6 +2596,19 @@ def _sync_session_key_after_compress(
         if not new_session_id or new_session_id == old_key:
             return
     
    +    lease_reanchored = _transfer_active_session_slot(
    +        sid,
    +        session,
    +        new_session_id=new_session_id,
    +    )
    +    if not lease_reanchored:
    +        logger.warning(
    +            "Compression session lease did not re-anchor: sid=%s old_session_id=%s new_session_id=%s",
    +            sid,
    +            old_key,
    +            new_session_id,
    +        )
    +
         try:
             from tools.approval import (
                 disable_session_yolo,
    ```

    ```diff
    @@ -4940,7 +5006,7 @@ def _session_live_title(session: dict, key: str) -> str:
     
     
     def _session_live_item(sid: str, session: dict, current_sid: str = "") -> dict:
    -    key = str(session.get("session_key") or sid)
    +    key = _session_lookup_key(session, fallback=sid)
         agent = session.get("agent")
         history = list(session.get("history") or [])
         status = _session_live_status(sid, session)
    ```

    ```diff
    @@ -4964,11 +5030,21 @@ def _session_live_item(sid: str, session: dict, current_sid: str = "") -> dict:
         }
     
     
    +def _session_lookup_key(session: dict, *, fallback: str = "") -> str:
    +    agent = session.get("agent")
    +    return str(
    +        getattr(agent, "session_id", None)
    +        or session.get("session_key")
    +        or fallback
    +        or ""
    +    )
    +
    +
     def _find_live_session_by_key(session_key: str) -> tuple[str, dict] | None:
         for sid, session in list(_sessions.items()):
             if session.get("_finalized"):
                 continue
    -        if str(session.get("session_key") or "") == session_key:
    +        if _session_lookup_key(session, fallback=sid) == session_key:
                 return sid, session
         return None
     
    ```

    ```diff
    @@ -5012,7 +5088,7 @@ def _live_session_payload(
             "messages": _history_to_messages(history),
             "running": running,
             "session_id": sid,
    -        "session_key": session.get("session_key") or sid,
    +        "session_key": _session_lookup_key(session, fallback=sid),
             "started_at": float(session.get("created_at") or time.time()),
             "status": _session_live_status(sid, session),
         }
    ```
- **#49086: fix(tui): preserve live session identity across compression**. closed without merge
  - maintainer direction: category `volume_quota`; implication `active`

## Fix status

- Merged to main in PR #51509 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-06-23`.
- Subsystem: `dashboard`