When a Claude Code /v1/messages request is bridged to a GPT model on the
Responses path (bridgedGptMessages), prior assistant text turns were lowered
to content parts of type input_text. The OpenAI Responses API requires
assistant-role message content to be output_text; input_text under
role:assistant is rejected with 400, breaking every multi-turn session to a
Responses-routed GPT model after the first assistant reply. The bridge's read
side already maps assistant text to/from output_text — only the write side was
wrong. Thread the role into inputParts and pick the text type accordingly;
user/system stay input_text.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Shubham Srivastava
fbe2c251b8