# Anthropic — Make long-running agents faster with message threads

- Company: Anthropic (anthropic.com)
- Announced: 2026-11-02
- Category: capability-change
- Coverage: not counted
- Announcement: yes
- Group: announcements
- Source: https://claude.com/resources/articles/message-threads
- Record: https://forck.live/items/30644-make-long-running-agents-faster-with-message-threads
- Subject: Claude
- Models affected: Claude
- Pricing: Standard Claude token rates and existing rate limits apply

Anthropic has put message threads into public beta on the Claude Platform, letting agents send only new messages instead of resending the whole conversation each turn. A coding agent can make hundreds of requests in one session, and once a conversation reaches hundreds of thousands of tokens, resending all of it delays Claude's first response. With message threads on by default for most Claude Code users, requests carrying 500k to 1M tokens see median time to first token fall by about 35%, Anthropic says. Developers add the thread parameter to Messages API requests: the first request carries the full conversation and opens a thread, and later requests carry only new messages plus the previous response ID. Anthropic holds each thread in memory, encrypted and not written to disk, and a thread expires 5 minutes after its last request, at which point the client resends the full conversation. Token usage stays the same because Claude still reads the full conversation on every turn, and the feature is available on the native Claude Platform, Claude Platform on AWS, Claude in Microsoft Foundry and Claude Models on Google Cloud.

## Evidence

Verbatim from https://claude.com/resources/articles/message-threads:

> Message threads is now available in public beta on the Claude Platform. With message threads, agents no longer need to resend the full conversation history on every turn, reducing latency for long-running sessions.
> 
> How message threads works
> 
> A coding agent might make hundreds of requests in one session, and each request resends every earlier message and tool result. Once a conversation reaches hundreds of thousands of tokens, resending all of it adds time before Claude starts responding. With message threads, agents send only what’s new since the last turn, which reduces time to first token (TTFT).
> 
> With message threads on by default for most Claude Code users, requests with 500k to 1M tokens see median TTFT drop by about 35%.
> 
> To use message threads, add the thread parameter to Messages API requests. The first request includes the full conversation and starts a thread. Each request after that includes only the new messages and the ID of the previous response. Between turns, we hold each thread in memory, where it’s encrypted and not written to disk. A thread expires 5 minutes after its last request and your client then resends the full conversation to start a new one.

## Follow-ups

- Unite.AI (reported, 2 Nov): Anthropic Launches Message Threads Beta for Long-Running Agents — https://forck.live/items/30665-anthropic-launches-message-threads-beta-for-long-running-agents

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Record: https://forck.live/items/30644-make-long-running-agents-faster-with-message-threads
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