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404Not retryable

Anthropic 404 Not Found

The URL or referenced resource doesn't exist — usually a typo'd model ID or a wrong API path.

Most likely causes

  1. 1.Model ID typo (e.g. claude-sonnet-4.5 instead of claude-sonnet-4-5)
  2. 2.Deprecated model that has been retired
  3. 3.Wrong base path (/v1/complete instead of /v1/messages)

Fix checklist

  • Copy the model ID exactly from the models documentation page
  • Hit /v1/models with your key to list what you can actually use
  • Pin model IDs in config, not inline strings scattered through code

Retry guidance

Not retryable — the resource won't appear on retry.

// 404 is NOT retryable — surface it and fix the request/config.
const res = await fetch("https://api.anthropic.com/v1/messages", {
  method: "POST",
  headers: {
    "content-type": "application/json",
    "x-api-key": process.env.ANTHROPIC_API_KEY!,
      "anthropic-version": "2023-06-01",
  },
  body: JSON.stringify(payload),
});
if (res.status === 404) {
  const body = await res.json();
  // Do not retry: log the provider's message — it names the exact problem.
  throw new Error(`Anthropic 404: ${JSON.stringify(body.error ?? body)}`);
}

Provider status page: status.anthropic.com