START pod: Austin Wang, Co-Founder & CEO, Manaflow "Building the open-source terminal for coding agents"

10 coding agents running in parallel.

Zero idea which one finished.

That was the problem.

Around November, Austin Wang and his co-founder Lawrence Chen stopped opening their IDE.

They weren't writing code by hand anymore

Everything ran through Claude Code and Codex in the terminal

10 panes. 10 agents. 10 copies of the repo.

And two problems appeared almost immediately.

They couldn't tell what each agent was working on.

They couldn't tell when an agent had finished.

So they built cmux.com:

Native macOS Ghostty-based terminal with vertical tabs, notifications, and built-in browser

Each workspace shows the task, branch, ports, and pull request - so you always know what every agent is doing.

When an agent finishes, it moves to the top with a blue notification ring.

Like iMessage...

But for coding agents.

Who's adopting it first?

Staff and senior engineers.

It makes sense.

They're already used to breaking large problems into smaller ones and delegating the work.

The difference now?

Instead of junior engineers, they're orchestrating dozens of coding agents in parallel.

Even Austin and his co-founder don't work the same way.

One prefers worktrees.

The other doesn't.

That's why cmux ships primitives, not prescriptions.

Developers build the workflow that fits them.

Because nobody has figured out the "right" way to work with coding agents yet.

And as those agents write more of the code...

The bottleneck won't be software.

It will be human attention.

 Austin Wang, Co-Founder & CEO, Manaflow on Fondo START pod

00:15 — Introducing cmux and the YC journey

00:00:50 — Pivoting from enterprise AI to dev tools

00:01:25 — Leaving the IDE for the terminal

00:02:00 — The problem that led to Arc-inspired workspaces 

00:02:45 — Notifications for coding agents

00:03:25 — Why developers are moving to terminal-first workflows 

00:04:30 — Why senior engineers adopt cmux first 

00:05:50 — Primitives over prescribed workflows

00:07:00 — The future of autonomous code review 

00:08:40 — Why human attention becomes the bottleneck

00:09:20 — Growing to 14.5K GitHub stars

00:11:15 — Building cmux for speed and performance

Check out cmux.com