Murmell vs Windsurf
Windsurf runs parallel agents by giving each conversation its own git worktree, a second copy of your files that you merge back when it is done. Murmell puts the agents in one directory on a cloud machine and settles who writes where before the write happens.
The real difference
Windsurf is explicit about the mechanism, which makes this an easy comparison to make honestly. Parallel agents get worktrees: a real second checkout of your files on a branch of its own, so one agent building and testing cannot disturb the workspace you are typing in. Arena mode goes further and gives each model its own worktree to compare answers on the same prompt.
That is isolation done properly, and it has the cost isolation always has. Twenty worktrees is twenty copies, and every one of them ends with a merge. The conflict is not avoided, it is deferred to the moment you press the button.
Murmell removes the copies. One directory, and an agent claims the paths it is about to touch before it writes. The board keeps one holder per path and refuses everybody else until it lets go, so a second agent waits for thirty seconds instead of producing a version of the file that has to be reconciled later.
Where Windsurf wins
The editor, and the fact that it is on your machine. Nothing is uploaded, the code stays on your disk, and the agents run against the same files you are looking at. Murmell has no self-hosted option, so if the code is not allowed to leave, that decides it.
The command centre is also a good answer to a real problem: agents running in more than one place need somewhere to be supervised from. It supervises them for one person, at one machine, which is where the two products part.
Which to pick
Windsurf when you are writing code by hand and want parallel runs beside you. Murmell when the agents are doing the writing, several at once, in the same corner of the project, and somebody else needs to watch. How the claim works.
Side by side
| Windsurf | Murmell | |
|---|---|---|
| Where a second agent works | Its own git worktree under ~/.windsurf/worktrees, up to twenty per workspace | One shared directory, after it claims the paths it is about to touch |
| Who can watch it happen | Whoever is at that machine, in the agent command centre | Anybody with the link, live, with a name on every cursor |
| Where the work lands | Your main workspace, once you press merge | A private repository for the project, pushed as the agents go |
Straight answers
How does Windsurf run several agents at once?
With git worktrees. Windsurf documents that each Cascade conversation gets its own session and worktree so it can edit, build and test without interfering with your main workspace, that worktrees live under ~/.windsurf/worktrees organised by repository, that a workspace holds up to twenty, and that you press merge to bring the changes back.
Is Windsurf still Windsurf?
It is Cognition's now, and the editor is being folded into the Devin line: Windsurf documents Cascade as legacy with an end-of-life date, replaced by a local agent under the Devin name. If you are choosing today, choose knowing the product is mid-rename.
Which should I pick, Windsurf or Murmell?
Windsurf when you are editing by hand and the parallel runs are yours alone on your own disk. Murmell when several agents need the same files in the same hour and other people need to see it happen.