Compared

Murmell vs Devin

Devin is an autonomous engineer you hand a ticket to. You come back to a pull request. Murmell is a canvas where you open several agents on one project and watch the real terminals while they work.

The real difference

Devin scales by separation. When a task is large it delegates to other Devins, and Cognition describes each one as “a full Devin, running in its own isolated virtual machine with its own terminal, browser, and development environment”. A coordinating session scopes the work, hands out the pieces and compiles the results.

Murmell scales by sharing. Every agent on a canvas works in the same checkout on the same cloud machine. Before an agent writes to a path it claims it. The board records one holder per path and refuses everyone else until the holder releases it, and that rule is enforced by the server rather than suggested to the model. A colliding write is snapshotted before it lands.

Splitting the work is a decision. Sharing a tree is a negotiation.

This changes what you can ask for. Work spread across isolated machines has to be split cleanly at the start, because nothing can be renegotiated once the copies have diverged. Agents in one tree renegotiate as they go: one takes the router file, the next waits for it, then takes it.

Where Devin wins

Devin is much further along at being left alone. It ships pull requests, picks up review feedback and CI results, and gets handed work from Linear, Slack and the other places your tickets already live. It starts each session from a saved machine snapshot, so your dependencies are installed before it types anything, and it reads its own past sessions to get better at your codebase over time.

If success means a ticket going in one end and a merged branch coming out the other, Devin is the product built for exactly that. Murmell asks more of you, because it is a room you sit in.

Which to pick

Pick Devin when work arrives as tickets that do not touch each other, and you would rather read the result than the run.

Pick Murmell when the change is one refactor across one tree, when you want to see the terminals as they type, or when the people you work with need to be on the same screen. Send a read link and they are in the room: the windows, the terminal contents and the named cursors, live. Read links are free and there is no cap on them. Close the tab and the agents keep working.

Both can be true in the same week. See what the canvas is.