
With Opus 4.8, you can add system instructions mid-conversation without breaking the prompt cache. More cache hits means lower cost and latency for your API requests.
Sometimes system instructions need to be updated during the course of a conversation or session. But editing the top-level system prompt field invalidates the prompt cache for everything that follows.
New in Claude Code (research preview): dynamic workflows. Claude writes an orchestration script on the fly, then spins up a large fleet of coordinated subagents in parallel to take on your most complex tasks. Use the word "workflow" in a prompt to get started.
Dynamic workflows are useful for tasks that are too big for a single agent loop, such as service-wide bug hunts, large migrations, or stress-testing a design. They're powerful and can be expensive, consuming a lot of tokens fast. Start with a scoped task to get a feel for it.