Claude 529 Overloaded: What It Means and How to Fix It

A 529 overloaded_error means Anthropic's API is temporarily out of capacity for the requested model across all users, unlike a 429, which reflects your own usage limits. The article recommends retrying with exponential backoff and jitter, then routing the same model to another provider via OpenRouter, which serves Claude Sonnet, Opus and Haiku 5.5 through five providers each, and optionally listing a fallback model with `models`. For Claude Code, it suggests switching models with `/model` or running Claude Code on OpenRouter via Ori Harness or three environment variables.