Shelbi vs Devin

At a glance

Where Shelbi excels

You own the machines, and there is no meter. Devin runs work in Cognition's cloud VMs and bills it as Agent Compute Units, where roughly one ACU is fifteen minutes of active work — great until light or bursty use turns into an unpredictable per-task cost. Shelbi runs entirely on hardware you already have: "no daemons, no servers," just ssh, tmux, git, and your agent CLI. Point it at the Mac mini in your closet and a Linux workstation, declare a few workers on each, and your spare compute becomes the fleet — with no VM clock running.

Bring your own agent — Shelbi is plumbing, not a model. Devin's intelligence is the product: its own SWE-1.6 model and an Adaptive router that picks a frontier model per task. Shelbi ships no model at all. It is agent-agnostic by design, driving "Claude Code, Codex, aider, anything with a CLI," declared per project. Run Claude Code on one worker and Codex on another in the same project, then swap a runner by editing a single line of YAML. When a better CLI lands next quarter, you adopt it without leaving Shelbi.

Review is a first-class pane, not just a pull request. Devin leans on autonomous PR generation that you review in GitHub or GitLab. Shelbi makes the human-in-the-loop step the center of the product: when a worker finishes, its card lands in a review column, Shelbi checks the branch out into a working directory on the machine that ran it, and spawns a fresh agent pane right there so you can interrogate the diff before anything merges. Press Enter on a review card, ask "why this approach?" in the agent's own pane, then approve and merge into your default branch — or push and open a PR with --pr.

Everything is plain text you can grep. Devin's task and run state lives in Cognition's platform, read back through a web app, REST endpoints, and consumption metrics. Shelbi keeps every task, log, and worker status as a markdown or YAML file on your disk — "grep it, version-control it, read it from your editor." A task is a markdown file with frontmatter you can diff; every column change appends one line to ~/.shelbi/events.log, so you can tail or audit the whole history after the fact. Each task also runs on its own git branch in its own worktree, so you review, merge, and archive them independently.

Where Devin excels

Genuine end-to-end autonomy from a ticket. Among coding agents, Devin is one of the furthest toward "ticket in, reviewed PR out": it plans, writes, runs tests, and debugs its own failures in one loop inside a real VM, equipped with a shell, an editor, and a browser. Shelbi orchestrates and supervises agents, but it does not supply that autonomous loop itself — your chosen CLI agent does the actual engineering.

Managed parallelism and enterprise governance. Devin's per-session-VM model lets one human supervise many concurrent tickets — Cognition cites 10+ implementations queued for review at once — and it pairs that with SSO, custom RBAC, audit logs, customer-managed keys, and dedicated or VPC deployment. That makes it credible inside large, regulated organizations. Shelbi has none of that compliance surface; it is your machines and your responsibility.

Repo-understanding tooling. Devin's DeepWiki (auto-generated, continuously updated architecture docs) and Ask Devin (semantic Q&A over an indexed repo) are well-regarded for onboarding both agents and humans onto an unfamiliar codebase. Shelbi has no equivalent built in — understanding the code is left to whichever agent you run.

Choosing

Choose Shelbi if you live in the terminal, have spare compute to spread agents across, and want your tasks, logs, and state to stay on your own disk in plain text. It fits when you want to drive whichever CLI agent is best this month and keep a hands-on review loop where you read every diff before it merges.

Choose Devin if you want a hosted teammate to delegate well-scoped tickets to with minimal setup, need parallel backlog burn-down or large mechanical migrations such as framework and Java upgrades or COBOL modernization, or need enterprise SSO, RBAC, audit, and VPC compliance out of the box.