STUPID-2026-0054

Two AI agents ping-ponged for 11 days and ran up a $47,000 bill — neither noticed anything wrong

4.1medium
May 20, 2026Verified

  1. Instruction given

    Run a research pipeline with an Analyzer agent and a Verifier agent.

  2. Expected behavior

    Detect when the pipeline is stuck and halt; cap spend.

  3. Actual behavior

    An Analyzer and a Verifier agent ping-ponged requests at each other for 11 days straight, generating a $47,000 bill. Because neither agent saw an error from its own perspective, no error was ever flagged and nothing stopped the loop.

  4. Damage

    $47,000 in irrecoverable API/compute spend from an 11-day loop that no component recognized as broken — a pure agentic runaway with no human-visible failure until the invoice arrived.

A research pipeline built from two cooperating AI agents — an Analyzer and a Verifier — ping-ponged requests at each other for 11 days, generating a $47,000 bill. The failure was subtle: from each agent's local perspective nothing was wrong, so neither ever flagged an error or triggered a stop. Agentic coding and research tools burn 10–100x more tokens than a chat window because the full, growing context is resent on every tool call, so a loop that no one notices compounds fast. It is the canonical runaway-cost failure: not a crash, not a deletion, but two confident agents amplifying each other indefinitely with no circuit breaker between 'making progress' and 'setting money on fire.'

Classification

Agent
Multiple Agents
Failure mode
Infinite Loop
Root cause
Confidence Miscalibration
Domain
Infra
Source
News Report

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