Claude Code can now do a multi-day job in one window

Hook

Jarred Sumner ported the Bun runtime from Zig to Rust on a Claude Code preview. 750,000 lines. Eleven days. 99.8% test compatibility. Today the feature he used has a name: dynamic workflows. Claude Code can now plan a job, run hundreds of parallel agents on its pieces in a single session, verify the work, and resume itself if it gets interrupted.

The news

Anthropic launched dynamic workflows in Claude Code on May 28, alongside Opus 4.8. What ships:

• Claude plans the job, breaks it into subtasks, spawns subagents (parallel Claude instances) to work them at the same time.
• Tens to hundreds of subagents in a single session.
• Results are independently verified, then iterated until they converge.
• Progress saves automatically. An interrupted job resumes where it left off.
• Available on Max, Team, and Enterprise plans. Claude Code CLI, desktop, VS Code, and the API.
• Turn it on per-prompt, or enable the ultracode setting to default-on.

Early customer quotes from the launch post: Klarna's Alessio Vallero said the feature surfaces dead code "that traditional static analysis missed." CyberAgent's Ken Takao called it "the gap between firing off a single subagent and building out a full agent team."

What it means for non-technical CEOs

For most teams, Claude Code has been a one-task-at-a-time tool. Open the terminal, give it a job, watch it work. Dynamic workflows raises that ceiling from "one task" to "the whole job." The unit of work that fits in a single Claude Code session just changed shape.

What used to be a multi-week migration is now a multi-day run. What used to be a security audit you scheduled a vendor for is now a session you start before bed. What used to be the cleanup nobody had time for is now a Sunday afternoon.

If your team has already learned Claude Code, this is the upgrade that pays for that investment again. If they haven't, the case for sitting down with them this week just got stronger.

The honest caveat: this is a research preview. Expect rough edges. Run it on a job where the failure mode is "redo it manually" not "explain it to the board."

What to do next

If you're on a Max, Team, or Enterprise plan, open Claude Code tonight and hand it the biggest job sitting on the team's backlog. The migration nobody's started. The audit nobody scheduled. The cleanup nobody had time for. Then enable ultracode and read what comes back in the morning.