Home/ Incident database/codex-runtime-runaway-loop-2026-06
Financial loss API cost spike verified

Codex Runtime stuck in a runaway inference loop burned credits with no project loaded

TWembley (OpenAI Codex Runtime user) · Jun 25, 2026 · Coding agent

What happened

A Codex Runtime user on Windows reported very high CPU during idle with no project loaded, plus high Defender CPU that normalized when Codex was closed. Two queries — a 15-line debug taking under five minutes and a follow-up on changed lines — wiped out a 5-hour usage limit. The app also created an empty .git directory in the project folder; deleting it collapsed the high CPU for both Codex and Defender. The issue was labeled bug, performance, and rate-limits, and remains open.

$0
Loss / impact
Jun 25
2026
API
Failure mode
Coding
Agent type

Causal vector

Runaway inference loop at idle / no project loaded; high CPU and token burn collapsed only when the app was closed

Source

Reported by GitHub issue, openai/codex #30061. Verified against the primary report.

Read the original report ↗

How a spend firewall would have helped

A pre-spend gate that caps per-run spend and detects a no-progress loop would have terminated the session after the first query instead of silently consuming the full limit.

The six rule types that contain this class of failure

Per-transaction cap

Any single spend above your ceiling is BLOCKED before it moves.

Daily total

Cumulative spend across all agent calls, bounded per day.

Velocity limit

Stops runaway retry loops — the #1 cause of overnight losses.

Merchant allowlist

Only approved destinations can ever receive funds.

Category rules

Flag high-risk classes (crypto, infra, refunds) for review.

Approval threshold

Above a value, the action waits for a human.

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