# Message threads

Anthropic released message threads in beta for the Claude Messages API: the API keeps the conversation on the server, so each later request sends only the new messages, making requests smaller and lowering time to first token for long conversations and agent loops. Previously such workloads had to resend the full history each turn. A thread expires 5 minutes after its last request and is deleted no more than 1 hour after its last use, and it is available on the Claude API, Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed), and Claude in Microsoft Foundry.

Anthropic released message threads in beta for the Claude Messages API: the API keeps the conversation on the server, so each later request sends only the new messages, making requests smaller and lowering time to first token for long conversations and agent loops. Previously such workloads had to resend the full history each turn. A thread expires 5 minutes after its last request and is deleted no more than 1 hour after its last use, and it is available on the Claude API, Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed), and Claude in Microsoft Foundry.

Anthropic has released message threads in beta on the Messages API, keeping long conversations and agent loops on the server so each later request sends only the new messages, which the release notes describe as smaller requests and a lower time to first token. Previously such multi-turn calls had to resend the full history each time. The feature uses the message-threads-2026-08-12 beta header, a thread expires 5 minutes after its last request and is deleted no more than 1 hour after last use, and it is available on the Claude API, Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed) and Claude in Microsoft Foundry.

Anthropic has released message threads in beta on the Messages API, keeping long conversations and agent loops on the server so each later request sends only the new messages, which the release notes describe as smaller requests and a lower time to first token. Previously such multi-turn calls had to resend the full history each time. The feature uses the message-threads-2026-08-12 beta header, a thread expires 5 minutes after its last request and is deleted no more than 1 hour after last use, and it is available on the Claude API, Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed) and Claude in Microsoft Foundry.

Anthropic has opened message threads in public beta on the Claude Platform, letting agents send only what is new since the last turn instead of resending the whole conversation history. Previously a coding agent could make hundreds of requests in one session, each carrying every earlier message and tool result, and once a conversation reached hundreds of thousands of tokens that resend added time before Claude began responding. With message threads on by default for most Claude Code users, requests of 500k to 1M tokens see median time to first token drop by about 35%, while Claude still reads the full conversation each turn, so token usage stays the same.

Anthropic has opened message threads in public beta on the Claude Platform, letting agents send only what is new since the last turn instead of resending the whole conversation history. Previously a coding agent could make hundreds of requests in one session, each carrying every earlier message and tool result, and once a conversation reached hundreds of thousands of tokens that resend added time before Claude began responding. With message threads on by default for most Claude Code users, requests of 500k to 1M tokens see median time to first token drop by about 35%, while Claude still reads the full conversation each turn, so token usage stays the same.