Workflow steps don't receive extended max duration — "maxDuration": "max" resolves to 800s, not the plan's 1800s (beta)

Extended max duration (Pro, beta) works for regular Next.js App Router functions on our team but never reaches Workflow DevKit step functions, which stay hard-capped at 800s.

Per-function opt-in is impossible for steps:

• The step route (app/.well-known/workflow/v1/step/route.js) is generated by @workflow/next and exports only HEAD/POST — no user-owned file for export const maxDuration.
• Placing the export in a "use workflow" source file fails the build: SWC transform error: Only async functions can be exported from a "use workflow" file.
• @workflow/next 4.1.0 and 5.0.0-beta.34 both emit no maxDuration and expose no option; the generated manifest declares "maxDuration": "max".

Measurements (same project, same deployment, 2026-07-15 — full repro with code in the gist below):

Environment: Vercel Pro, Fluid Compute on, Node 22.x, no Secure Compute/Static IPs, workflow 4.6.0. Repro (two files + build log + run/deployment IDs): https://gist.github.com/bwiesner/bd03e1875d70a5cb2d82750dd8968ad8

This looks like the resolution of "max" lagging the beta — per @pranaygp in #1483, "Step routes will automatically use the maximum possible maxDuration available on your vercel plan," which our plan's Control A shows should now be 1800.

Ask: resolve steps' "maxDuration": "max" to the extended maximum for eligible teams, or expose a per-step / plugin-level maxDuration option. (If the extended resolution is behind a staged rollout, confirming that would also settle it.)

Filed at the request of Vercel support (shared Slack thread with the team).