TL;DR
A practical, production-tested way to run multiple AI coding agents in parallel: use tmux to split “PM / Planner / Worker” roles, and use a lightweight Markdown “Feature Design (FD)” spec as the handoff artifact so agents don’t step on each other.
What this is about
Manuel Schipper describes a workflow for managing 4–8 simultaneous coding agents with a simple operating system: tmux windows for roles, and an FD document that moves through clear lifecycle stages from “Planned” to “Closed”.
Key points
- FD (Feature Design) as the contract: problem statement, options considered (with pros/cons), chosen approach, file-level plan, and verification steps.
- Role separation reduces chaos: a Planner writes/edits the FD; a Worker implements from a “ready” FD; a PM grooms backlog and sequencing.
- Slash-command ergonomics: shortcuts like
/fd-new,/fd-status,/fd-verify, and a one-time/fd-initbootstrap make the workflow reusable across repos. - Parallelism has limits: FD dependencies and human attention become the bottleneck; around ~8 agents is described as a practical cognitive ceiling.
Why it matters
Most “multi-agent coding” advice falls apart when you try to run it daily. The core idea here is to make concurrency safe by standardizing the handoff: the FD file becomes the shared source of truth, so the Worker agent can execute confidently while the Planner/PM continue elsewhere. It’s also a reminder that the best scaling trick is often operational, not model-side.
Practical takeaways
- If agents keep re-litigating decisions, force the decision into a short spec (FD) and have the Worker treat it as immutable input.
- Use tmux (or any multiplexing setup) to keep role context separate: “planning” and “execution” don’t mix well in one thread.
- Add explicit verification steps to the FD so the Worker can self-check before handing back.
Caveats / what to watch
- Even with specs, you can’t parallelize features that are tightly coupled—expect sequencing work.
- Long-running agent sessions can lose context; plan for checkpoints and short re-orientation notes in the FD.