Claude Managed Agents dynamic workflows: orchestrate up to 1,000 agents

Claude Managed Agents added dynamic workflows in public beta. A lead agent writes a multi-phase plan, distributes the phases across many worker agents, and merges what comes back into one result. The feature is enabled through a multiagent type, and Anthropic says a single workflow can reach up to 1,000 agents. The evidence offered is a bug-hunting benchmark: with 70 bugs planted in a codebase, the orchestrated run found 66 per run, while a single agent found between 14 and 27. That gap is large enough to change how teams approach broad, parallelizable work such as audits, migrations and test sweeps. The cost is real, though. Anthropic notes that the approach spends more tokens, and it recommends starting with scoped tasks rather than pointing a thousand agents at an open-ended goal. The practical reading is that fan-out pays when the work splits cleanly into independent pieces and the merge step can check results, and that a single agent remains the cheaper default when it cannot.