What
The Workflow orchestration engine dispatches multiple agents at once, and the maximum number running concurrently was previously fixed at a computed value based on your machine's CPU count (between 2 and 16). That cap can now be overridden by setting the CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS environment variable, and a debug log line now reports whichever value is actually in effect.
Why
This gives more control over how many agents a workflow runs at once, useful for tuning resource usage on a given machine or lifting the default cap for larger workflows.
Names in the bundleCLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS, on Environment variables.
| `CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS` | How many agents a single [workflow](/docs/en/workflows) run executes at once, from `1` to `256`. By default, a run executes up to 16 agents at once, fewer when Claude Code has fewer CPUs ava…env-vars see the edit
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS, on Environment variables.
Anthropic's release notes agree
Added CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS (1–256) to raise the Workflow tool's per-run concurrent agent limit for inference-bound…
The name it cites is new in this build
New in this build: CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS