AGENT FAILURE SERIES #12 of ∞ spinlock — the loop your STOP button can't end

SpinLock — Infinite Loop Detector

An AI agent enters a loop. It calls the same tool. Gets the same error. "Corrects" itself. Calls the tool again. You hit STOP. Nothing happens. The API bill climbs. This is the production failure nobody demos — because watching it happen is the whole lesson.

AGENT EXECUTION LOG 0 actions
LIVE METRICS
SPINNING
LOOP ITERATIONS
0
task not complete
ESTIMATED API COST
$0.0000
per token: $0.000003
TOKENS CONSUMED
0
⟳ RUNNING
DEVELOPER CONTROLS

CIRCUIT BREAKER INJECTED

REAL PAIN SIGNALS ↗ "ran 6h on a 2-min task, cost $200" (Jul 11)
↗ "drains API budget in 10 minutes" (Jul 24)
↗ "$4 figures overnight from infinite loop" (Jul 3)
↗ "wrote the same file six times in a row" (Jul 20)

// POSTMORTEM

ROOT CAUSE

WHY STOP DIDN'T WORK

The STOP signal was sent to the orchestrator's event queue — but the agent was mid-iteration and the loop had no checkpoint. It processed STOP as input, reasoned "not done yet", and continued.

THE FIX (3 lines)