[Bug]: /v1/messages streaming delays message_start until the model’s thinking pass finishes, even with no fallbacks configured
![[Bug]: /v1/messages streaming delays message_start until the model's thinking pass finishes, even with no fallbacks configured](https://www.chat-gpts.plus/wp-content/uploads/2026/09/39431-85498499-768x403.jpg)
这个报错通常出现在 LiteLLM 代理以 /v1/messages 流式转发带 adaptive thinking 的 Bedrock/Anthropic 模型时:即使配置里没有 fallback, message_start 和 content_block_start 也会被 Router 缓冲








