From b47ad9c60f960dc8bcc8502426844e9c9285ea2c Mon Sep 17 00:00:00 2001
From: ciregenz <ciregenz@berkeley.edu>
Date: Sun, 9 Aug 2026 14:08:34 -0700
Subject: [PATCH] [eric] agents: active time is stall-capped inter-event work,
 so one wedged turn can't book 54 hours of 'agent time'

---
 backend/apps/agents/manager/run/TurnRunner.py |  7 +++++
 .../apps/agents/manager/streaming/state.py    |  4 +++
 .../apps/agents/manager/streaming/thinking.py |  9 ++++---
 backend/tests/test_agent_active_time.py       | 26 +++++++++++++++++++
 4 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 backend/tests/test_agent_active_time.py

diff --git a/backend/apps/agents/manager/run/TurnRunner.py b/backend/apps/agents/manager/run/TurnRunner.py
index cc247713..633017e4 100644
--- a/backend/apps/agents/manager/run/TurnRunner.py
+++ b/backend/apps/agents/manager/run/TurnRunner.py
@@ -107,6 +107,13 @@ class TurnRunner(AgentManagerProtocol):
                     flight_recorder.crumb(session_id, "first-event", kind=type(message).__name__)
                     turn.first_event = False
 
+                # Active-time ledger: count the gap since the previous event, capped so a stall
+                # (approval wait, paused workflow, provider backoff) can't book its wall-clock.
+                p_now_ts = time.time()
+                if turn.last_event_ts is not None:
+                    turn.active_ms += int(min(p_now_ts - turn.last_event_ts, 30.0) * 1000)
+                turn.last_event_ts = p_now_ts
+
                 # Log system messages (MCP server status, errors, etc.)
                 if isinstance(message, SystemMessage):
                     raw = message.__dict__ if hasattr(message, '__dict__') else str(message)
diff --git a/backend/apps/agents/manager/streaming/state.py b/backend/apps/agents/manager/streaming/state.py
index ae1b8562..77afc4fd 100644
--- a/backend/apps/agents/manager/streaming/state.py
+++ b/backend/apps/agents/manager/streaming/state.py
@@ -45,6 +45,10 @@ class TurnState(BaseModel):
     tool_count: int = 0
     started_ts: Optional[float] = None
     total_ms: int = 0
+    # ACTIVE time: sum of inter-event deltas with stall gaps capped, so a turn that waits an hour
+    # on an approval or a wedged workflow books seconds of work, not the wall gap (ENG-189).
+    last_event_ts: Optional[float] = None
+    active_ms: int = 0
     output_tokens: int = 0
     assistant_text_chars: int = 0
     tool_input_chars: int = 0
diff --git a/backend/apps/agents/manager/streaming/thinking.py b/backend/apps/agents/manager/streaming/thinking.py
index aa788e34..8d4c4635 100644
--- a/backend/apps/agents/manager/streaming/thinking.py
+++ b/backend/apps/agents/manager/streaming/thinking.py
@@ -86,11 +86,14 @@ async def emit_consolidated_thinking(thinking: ThinkingState, turn: TurnState, s
             pass
     if turn.started_ts is not None:
         turn.total_ms = int((time.time() - turn.started_ts) * 1000)
-        # Accumulate into session-level "agent active time" and the per-model breakdown so a session that spans multiple turns reports the total wall-clock time the agent was running. Per-model bucket uses the model active *now* (model can be switched mid-turn but the current value is the right attribution for the work just produced).
+        # Session-level "agent active time" books ACTIVE ms (stall-capped inter-event deltas), not
+        # turn wall-clock: one 9-message session once booked 54 hours by waiting (ENG-189). Fallback
+        # to wall-clock only when no events accrued (a turn that died before its first event).
         try:
-            session.agent_active_ms = int(getattr(session, "agent_active_ms", 0) or 0) + turn.total_ms
+            p_worked_ms = turn.active_ms if turn.active_ms > 0 else turn.total_ms
+            session.agent_active_ms = int(getattr(session, "agent_active_ms", 0) or 0) + p_worked_ms
             m = session.model or "unknown"
-            session.time_per_model[m] = int(session.time_per_model.get(m, 0)) + turn.total_ms
+            session.time_per_model[m] = int(session.time_per_model.get(m, 0)) + p_worked_ms
         except Exception:
             pass
     if thinking.msg_id is None:
diff --git a/backend/tests/test_agent_active_time.py b/backend/tests/test_agent_active_time.py
new file mode 100644
index 00000000..20fb2832
--- /dev/null
+++ b/backend/tests/test_agent_active_time.py
@@ -0,0 +1,26 @@
+"""ENG-189: agent_active_ms means time the agent was producing, not turn wall-clock. A stalled
+gap between events books at most the 30s cap, so one wedged turn can't be 92% of the metric."""
+
+from backend.apps.agents.manager.streaming.state import TurnState
+
+
+def p_feed(turn: TurnState, ts: float) -> None:
+    if turn.last_event_ts is not None:
+        turn.active_ms += int(min(ts - turn.last_event_ts, 30.0) * 1000)
+    turn.last_event_ts = ts
+
+
+def test_stalled_gap_books_the_cap_not_the_wall():
+    turn = TurnState()
+    p_feed(turn, 1000.0)
+    p_feed(turn, 1001.0)      # 1s of work
+    p_feed(turn, 4601.0)      # a 1-HOUR stall books 30s, not 3600s
+    p_feed(turn, 4602.5)      # 1.5s more work
+    assert turn.active_ms == 1000 + 30_000 + 1500
+
+
+def test_busy_turn_books_real_time():
+    turn = TurnState()
+    for i in range(11):
+        p_feed(turn, 100.0 + i * 0.5)
+    assert turn.active_ms == 5_000