Message threads
Anthropic added message threads in beta to the Claude Messages API, which keeps the conversation on the server so later requests send only new messages.
Long conversations and agent loops can now send smaller requests and get a lower time to first token. The API stores the conversation on the server, so each later request carries only the new messages. A thread expires 5 minutes after its last request and is deleted no more than 1 hour after its last use.
- Date
- Monday 2 November 2026
- Lab
- Anthropic
- Kind
- feature
- Access
- closed API
Figures
| Measure | Value | Measured by |
|---|---|---|
| Thread expiry after last request | 5 minutes deleted no more than 1 hour after last use | company |
Beta, requires the message-threads-2026-08-12 beta header. Available on the Claude API, Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed) and Claude in Microsoft Foundry.
Sources
This record was checked against its sources on 2 November 2026. How we check