English | Русский

Session Active Time (v1.4)

SENAR Rule 9.2 limits a session to 180 minutes. In v1.4 that 180 is active time, not wall-clock — long pauses are clipped to the idle threshold instead of being dropped entirely. This page explains the algorithm, the semantics choice (clip vs exclude), and how to tune the threshold.

Why Active Time

Wall clock punishes natural breaks. A session that starts at 09:00, pauses for an hour-long meeting, and resumes at 11:00 would hit "120 min" without the agent doing 120 min of work. v1.3+ fixes that by computing gap-based active time: a bounded sum of inter-tool-call intervals.

Algorithm

Every tool call writes a row to events (via the activity_event.py PostToolUse hook). Active time is the bounded sum of intervals between consecutive timestamps:

active_seconds = Σ min(t[i+1] − t[i], idle_threshold_seconds)

Each gap is clipped at idle_threshold (default 600 s / 10 min). A long AFK gap (e.g. three hours) contributes exactly the threshold to active — enough to credit "the agent worked right before pausing", but not enough to give a multi-day session for free against the Rule 9.2 budget.

events:    t1   t2   t3 ---(huge gap)--- t4   t5
intervals: Δ1   Δ2   Δ3(clipped→10m)     Δ4
active     = Δ1 + Δ2 + 10m + Δ4
wall       = t5 − t1

v1.4 polish (v14b-session-active-time) flipped the semantics from "exclude" (gap ≥ threshold → 0) to "clip" (gap ≥ threshold → threshold). Clip is more conservative: a long AFK still spends ~10 min against the limit, so an agent can't run a multi-day session for free.

Threshold Configuration

.tausik/config.json:

{
  "session_idle_threshold_minutes": 10,
  "session_max_minutes": 180,
  "session_warn_threshold_minutes": 150,
  "session_capacity_calls": 200
}

Knob	Default	Meaning
session_idle_threshold_minutes	10	Gaps above this clip to the threshold (each long AFK contributes exactly this much to active time, not zero)
session_max_minutes	180	Hard limit — task_start blocks above this (session extend to override)
session_warn_threshold_minutes	150	Soft warning starts here
session_capacity_calls	200	Capacity gate (in tool calls, not minutes) that QG-0 evaluates on task_start

Where You See It

tausik status shows both numbers when a session is open:

Session: 76m active / 145m wall

tausik doctor echoes the same.

Retro Computation

If you tune the idle threshold or want to see how a past session looked under a different setting, run:

.tausik/tausik session recompute

This re-walks session_activity events for past sessions and prints wall vs active per session. The recompute is read-only — it does not mutate the stored values unless you pass --write (where supported).

Activity Hook

scripts/hooks/activity_event.py is the PostToolUse hook that stamps (session_id, tool_name, timestamp) into session_activity. It runs on every tool call. Disable with TAUSIK_SKIP_HOOKS=1 only for debugging — disabling it makes active time stop accumulating until re-enabled.

Override / Extend

If you legitimately need a longer session (e.g. release day):

.tausik/tausik session extend --minutes 60

task_start --force is a separate escape hatch that bypasses the capacity gate with an audit-event trail; it is not a substitute for session extend.

Negative — What Active Time Is Not

• It is not wall clock — long pauses are dropped above the idle threshold.
• It is not an estimate of real focused-work time. Tool calls are the proxy; if you read code in your head without tool use, the timer pauses.
• The 180 limit is on active, not wall. A session that has been open for 12 hours with 30 min of activity is still at 30 min and well under the limit.

What's Next

• Configuration — full list of knobs in .tausik/config.json
• CLI Commands — session start/extend/recompute reference
• Hooks — the activity hook and other PostToolUse hooks