Nth Counting

Network and WebSocket rules can include one counting selector.

Field	Meaning
onNth	Apply only on the Nth matching request or message.
everyNth	Apply on every Nth matching request or message.
afterN	Apply after the first N matches have passed.
firstN	Apply on the first N matches only, then never again.

network: {
  failures: [
    { urlPattern: '/api/orders', statusCode: 503, probability: 1, onNth: 3 },
  ],
}

firstN is the rate-limit shape: fail the first attempts, then let retries through. The ai-retry-loop preset uses firstN: 2 to return 429 twice before a clean response.

network: {
  failures: [
    { urlPattern: '/api/chat', statusCode: 429, probability: 1, firstN: 2 },
  ],
}

Counting is per rule object and shared across fetch and XHR for the same config entry. Set at most one of onNth, everyNth, afterN, or firstN on a rule.