refactor(agent): fail loudly on a missing turn clock; single lowercase in is_dangerous_confirmation

- build_api_messages reads agent._current_turn_timestamp directly: a caller that skipped the
  turn prologue now raises instead of silently falling back to per-request wall time, which
  would re-create the mid-turn drift the fix removes. Only production caller
  (assemble_api_request) runs after _reset_per_turn_agent_state; cross-reference to the
  tripwire _inflight_turn_started so the two clocks are not "unified" by mistake.
- is_dangerous_confirmation lowercases once instead of once per pattern (now on the per-request path).
- Tests: one _send(idx=) helper instead of three spellings of the builder call; the
  untrustworthy-stamp contract is its own test.

agent/replay_cleanup.py

@@ -196,7 +196,10 @@ _EXPIRED_CONFIRMATION_SENTINEL = (
 
 def is_dangerous_confirmation(content: Any) -> bool:
     """True if user-message text contains a known dangerous confirmation phrase."""
-    return isinstance(content, str) and any(pattern in content.strip().lower() for pattern in _DANGEROUS_CONFIRMATION_PATTERNS)
+    if not isinstance(content, str):
+        return False
+    lowered = content.strip().lower()
+    return any(pattern in lowered for pattern in _DANGEROUS_CONFIRMATION_PATTERNS)
 
 
 def strip_stale_dangerous_confirmations(

agent/turn_context.py

@@ -510,7 +510,8 @@ def _reset_per_turn_agent_state(agent: Any) -> None:
         _reset_consol()
     # Expiry clock for build_api_messages: admission time (not the input's platform-event
     # stamp, which can predate admission by minutes), frozen so every request this turn
-    # sends identical bytes.
+    # sends identical bytes. Distinct from note_turn_start's _inflight_turn_started, a
+    # tripwire slot cleared at persist.
     agent._current_turn_timestamp = time.time()
 
     # Pre-turn connection health check: clean up dead TCP connections.
@@ -1062,8 +1063,10 @@ def build_api_messages(
     # calls/results) are live and must never be rewritten between iterations. The
     # expiry clock is the turn's admission time, frozen in _reset_per_turn_agent_state.
     # Without an anchor (compaction found no surviving user row) there is no provable
-    # persisted prefix, so nothing is canonicalized.
-    turn_now = getattr(agent, "_current_turn_timestamp", None) or time.time()
+    # persisted prefix, so nothing is canonicalized. The clock is stamped once per turn in
+    # _reset_per_turn_agent_state; a caller that skipped the prologue fails loudly here
+    # rather than silently un-freezing it.
+    turn_now = agent._current_turn_timestamp
     split = current_turn_user_idx if has_current else 0
     canonical_messages = canonicalize_replay_history(messages[:split], now=turn_now) + messages[split:]
 

tests/agent/test_replay_cleanup.py

@@ -125,10 +125,10 @@ def _wire(messages):
     return json.dumps(ChatCompletionsTransport().convert_messages(list(messages)), sort_keys=True)
 
 
-def _send(agent, history):
+def _send(agent, history, idx=None):
     request, _ = build_api_messages(
-        agent, history, current_turn_user_idx=len(history) - 1, ext_prefetch_cache="",
-        plugin_user_context="", moa_config=None, active_system_prompt="",
+        agent, history, current_turn_user_idx=len(history) - 1 if idx is None else idx,
+        ext_prefetch_cache="", plugin_user_context="", moa_config=None, active_system_prompt="",
     )
     return request
 
@@ -177,17 +177,14 @@ def test_send_wire_matches_replay_wire_after_db_round_trip(tmp_path):
             {"id": "c4", "type": "function", "function": {"name": "search_files", "arguments": "{}"}}]},
         {"role": "tool", "tool_call_id": "c4", "content": "[Command interrupted]"},
     ]
-    request2 = build_api_messages(
-        _SendAgent(), live, current_turn_user_idx=len(persisted), ext_prefetch_cache="",
-        plugin_user_context="", moa_config=None, active_system_prompt="",
-    )[0]
+    request2 = _send(_SendAgent(), live, idx=len(persisted))
     assert _wire(request2[: len(request)]) == _wire(request)
     assert request2[-1]["content"] == "[Command interrupted]"
 
 
-def test_confirmation_expiry_uses_frozen_admission_clock_and_fails_closed(monkeypatch):
+def test_confirmation_expiry_uses_frozen_admission_clock(monkeypatch):
     """Expiry is judged once per turn at admission (not the input's event stamp, not
-    per-request wall time); a present-but-corrupt stamp is treated as expired."""
+    per-request wall time)."""
     from agent.turn_context import _reset_per_turn_agent_state
 
     agent = _SendAgent()
@@ -211,11 +208,13 @@ def test_confirmation_expiry_uses_frozen_admission_clock_and_fails_closed(monkey
         {"id": "c1", "type": "function", "function": {"name": "read_file", "arguments": "{}"}}]},
         {"role": "tool", "tool_call_id": "c1", "content": "ready"}]
     monkeypatch.setattr("agent.turn_context.time.time", lambda: 10_500.0)  # ...however long the tools take
-    late = build_api_messages(agent, history, current_turn_user_idx=2, ext_prefetch_cache="",
-                              plugin_user_context="", moa_config=None, active_system_prompt="")[0]
-    assert late[0]["content"] == "confirm reboot"
+    assert _send(agent, history, idx=2)[0]["content"] == "confirm reboot"
 
-    for untrusted in ("nan", 96_400.0, 4_000_000_000.0):  # corrupt, or issued in the future
+
+def test_untrustworthy_confirmation_stamp_fails_closed():
+    """A corrupt or future stamp on a dangerous confirmation cannot vouch for its age: the
+    text and its sidecar expire. A missing stamp (legacy row) is still left alone."""
+    for untrusted in ("nan", 96_400.0, 4_000_000_000.0):
         row = [{"role": "user", "content": "confirm reboot", "timestamp": untrusted, "api_content": "confirm reboot"}]
         out = canonicalize_replay_history(row, now=10_000.0)
         assert "EXPIRED" in out[0]["content"] and "api_content" not in out[0], untrusted