thaki-AI/daily-paper-2026-08-04-event-vs-cron-agent-automation

Event-Driven vs. Time-Cron Triggering for Autonomous Agent Harnesses: Measuring the Latency-Cost Frontier and Idempotency Requirements

TL;DR — Event-driven triggering Pareto-dominates fixed-interval polling for autonomous agent harnesses: push achieves 1.997 s mean latency at 12.12 cost units, while the fastest polling wastes 713x more compute for 2.5x worse latency, and the cheapest polling matches cost but is 1661x slower. Idempotency-key deduplication is required, not optional — removing it causes 3.9% of delivery attempts to double-fire.

ThakiCloud AI Research · 2026-08-04 · 📝 Tech blog (KO)

Problem

Unattended autonomous agent harnesses overwhelmingly rely on fixed-interval polling to detect state changes, but the polling interval is chosen by intuition, not measurement. Short intervals waste compute on idle wake-ups; long intervals sacrifice latency. The tradeoff is never quantified.

Approach

A controlled, reproducible discrete-event simulation of a Poisson state-change process (4 events/hour, 98 events, 24 simulated hours, seed=42) comparing 10 fixed polling intervals against an event-driven push model with duplicate delivery, idempotency-key deduplication, handler failure, retry, and dead-lettering — both arms observe an identical event stream.

Key contributions

• A reproducible latency-cost frontier showing that no polling interval simultaneously matches push on both axes, giving operators a quantitative basis for migration decisions instead of intuition alone.
• A quantification of wasted computation in polling loops: at common production defaults, 93.61% (60 s) to 98.88% (10 s) of poll invocations wake to find nothing, framing idle polling as a fleet-scale compute and energy waste problem.
• An idempotency-key ablation showing that 3.9% of delivery attempts would incorrectly re-fire the downstream action without deduplication, establishing idempotency-key deduplication and dead-lettering as required co-requisites of push delivery under at-least-once semantics.

Figures

At common production defaults, polling waste is extreme: 98.88% at 10 s and 93.61% at 60 s wake to find nothing. Only at intervals above 1800 s does waste fall below 20%, at the cost of ~16-minute mean latency. (Simulated 24-hour window, 98 Poisson events (rate=4/hour, seed=42).)
_{Simulated 24-hour window, 98 Poisson events (rate=4/hour, seed=42).}

Push achieves 2.5x lower latency than the fastest polling while spending 713x less compute. The cheapest polling matches push on cost but incurs 1661x higher latency. (Derived ratios from measured simulation outputs (seed=42). Push: mean=1.997 s, cost=12.12 units. Fastest poll (10 s): mean=5.086 s, cost=8640 units. Cheapest poll (7200 s): mean=3318.250 s, cost=12.0 units.)
_{Derived ratios from measured simulation outputs (seed=42). Push: mean=1.997 s, cost=12.12 units. Fastest poll (10 s): mean=5.086 s, cost=8640 units. Cheapest poll (7200 s): mean=3318.250 s, cost=12.0 units.}

Results (as argued)

Push: 1.997 s mean latency at 12.12 cost units, 98/98 correct actions, 3.9% double-fire rate without idempotency. Fastest polling (10 s): 5.086 s at 8640 units (713x cost, 2.5x worse latency). Cheapest polling (7200 s): 3318.250 s at 12.0 units (1661x worse latency). All figures from single-seed simulation; field validation remains future work.

Limitations

Single synthetic Poisson arrival process at one rate (4 events/hour), single random seed (42), i.i.d. failure model (real failures are correlated and bursty), simplified uniform cost model omitting cold-start latency and standing infrastructure costs. Findings are scoped to single-harness, moderate-rate regimes.

Abstract

Unattended autonomous agent systems are commonly assembled as collections of scheduled jobs that wake at fixed intervals, inspect external or internal state, and act only if something changed. Polling is easy to reason about and requires no push infrastructure, but it imposes a tradeoff between detection latency and wasted computation that operators typically tune by intuition rather than measurement. We ask how much latency and wasted computation an event-driven trigger saves relative to fixed-interval polling at fixed correctness, and what idempotency and dead-letter design is required to make push delivery safe under at-least-once semantics. We built a controlled, reproducible discrete-event simulation of a Poisson state-change process at four events per hour over twenty-four simulated hours and compared ten fixed polling intervals against a simulated event-driven push model with duplicate delivery, deduplication, handler failure, retry, and dead-lettering. No infrastructure was deployed and no live traffic was measured; every number reported is a simulation output. Within the simulated frontier, no polling interval simultaneously matched push on both axes: push achieved a mean detection latency of 1.997 seconds at 12.12 cost units, while the fastest polling interval cost 8640 units for a worse mean latency of 5.086 seconds, and the cheapest polling interval matched push on cost but was roughly three orders of magnitude slower. An ablation removing idempotency-key deduplication showed that about 3.9 percent of delivery attempts would incorrectly re-fire the downstream ac

Files

• 📄 Paper (PDF)
• LaTeX source
• References (BibTeX)

Citation

@techreport{thaki_event_vs_cron_agent_automation_2026,
  title  = {Event-Driven vs. Time-Cron Triggering for Autonomous Agent Harnesses: Measuring the Latency-Cost Frontier and Idempotency Requirements},
  author = {ThakiCloud AI Research (Hyojung Han)},
  year   = {2026},
  institution = {ThakiCloud}, note = {thaki-AI/daily-paper-2026-08-04-event-vs-cron-agent-automation}
}

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