Claude Code 2.1.231

你想把 Slack 接進 Claude，卻在登入畫面繞了一圈又回到錯誤訊息，問題可能不在你的帳號。MCP（Model Context Protocol，讓 AI 連接外部工具的協定）登入時，伺服器會比對回傳網址。有些服務會使用預先登記好的 OAuth client（用來核對身分的登入設定），原本的網址比對卻對不上。現在這種 redirect URI mismatch（回傳網址不一致）已修好，包含 Slack 這類伺服器。像寄件人與收件人地址其實一致，分揀台以前卻誤判格式不同而退件；現在能把信送回正確入口。

If you tried to connect Slack to Claude and were sent from sign-in straight back to an error, your account may not have been the problem. During MCP (Model Context Protocol, the protocol that connects AI to external tools) sign-in, the server compares the return URL. Some servers, including Slack, use a pre-registered OAuth client, and that comparison could fail. The redirect URI mismatch is now fixed. It was like a mail sorter rejecting a letter whose address was right but written in a format it did not expect; it can now send the letter to the proper entrance.