Mid-conversation tool changes enter beta on the Claude API
BetaVerifiedAdded Sep 22, 2026
Add or remove tools between turns while preserving the prompt cache on Claude Fable 5, Mythos 5, Opus 4.8 and Opus 5, using the mid-conversation-tool-changes-2026-07-01 beta header.
Topics: LLMs
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More Claude Platform releases
Every Claude Platform release| Date | Release | Type |
|---|---|---|
| Jul 24 | Claude Opus 5 launches with a 1M token context window at $5 / $25 per MTok GA | GA |
| Jul 24 | Claude Opus 5 only allows disabling thinking at effort high or below Update | Update |
| Jul 24 | Effort is the primary control for Claude Opus 5 Update | Update |
| Jul 24 | Claude API fallbacks parameter adds a default mode for recommended fallbacks Beta | Beta |
| Jul 24 | Fast mode removed for Claude Opus 4.7 Deprecation | Deprecation |
| Jul 22 | Claude Managed Agents agents accept an effort level in model configuration Update | Update |
| Jul 22 | Claude Managed Agents webhooks cover environment and memory store lifecycle Update | Update |
| Jul 22 | Claude Managed Agents sessions can be seeded with initial events Update | Update |
