Use Claude Code dynamic workflows: describe a task, get a JS orchestration script running up to 1,000 subagents

Anthropic·high signal

Claude Code's new dynamic workflows (research preview, June 2026) have Claude write a JavaScript orchestration script for a task you describe; a background runtime runs it, coordinating tens to hundreds of subagents in parallel (up to 1,000 per run, 16 concurrent), holding state in script variables and verifying results before they reach you. Jarred Sumner used it to port Bun from Zig to ~750K lines of Rust with 99.8% of tests passing in eleven days, two reviewers per file.