Claude API 'message threads' in public beta: send only new messages and the server remembers the conversation
First seen on X 6 hours ago@ClaudeDevs ♥ 4,37310 views
Anthropic released 'message threads' on the Claude Messages API in public beta. Instead of resending the full history each turn, you send the new messages and the previous message ID.
The ClaudeDevs account said on Nov. 2 that the API caches the conversation on the server so requests get smaller and Claude starts responding sooner. The post drew 4,300 likes.
Per the official release notes, you opt in with the `message-threads-2026-08-12` beta header. A thread expires 5 minutes after the last request and is deleted within an hour of last use. It is available on the Claude API, Claude Platform on AWS, Google Cloud and Microsoft Foundry.
The same notes say fast mode for Opus 4.8 is deprecated and will error after Nov. 30; migrate to Opus 5.5. Anthropic also opened applications for its paid Anthropic Residency through Nov. 22 (7,500 likes).
“Message threads are now in public beta on the Messages API.”
