Cognition Playground
An overview of Devin, Cognition’s AI software engineer.
Cognition builds Devin, an autonomous AI software engineer. Devin takes a task described in plain English and works it end to end: reading the codebase, planning, writing and running code, and opening a pull request for review.
How it works
Each session runs on its own cloud machine with a shell, a filesystem, an editor, and a browser. That environment is what lets Devin do more than suggest code — it installs dependencies, runs the test suite and linters, iterates on failures, and clicks through the running app in a browser to check its own work before handing anything back.
Where it fits
- Bug fixes and small features that are well specified but tedious.
- Migrations and refactors repeated across many files or repos.
- Test coverage, flaky-test triage, and CI failures.
- Codebase questions — tracing how something works before you change it.
- Code review on pull requests opened by people or by Devin.
How it compares
Most AI coding tools sit somewhere on a line from autocomplete to autonomy. Cursor and the IDE assistants keep you in the editor, driving every step. Terminal agents like Claude Code and OpenAI’s Codex CLI take a whole task but run on your machine, in your session, while you watch. Devin and Factory’s Droids push further: a task goes to a remote machine, runs unattended, and comes back as a pull request. The practical difference is less about model quality than about how much of the loop — environment, execution, verification, review — the tool owns.
| Tool | Shape | Runs where | You are |
|---|---|---|---|
| Devin | Autonomous agent with its own machine | Cloud VM per session, many in parallel | Reviewing PRs |
| Factory Droid | Autonomous agents, org workflow focus | Cloud or local | Reviewing PRs |
| Claude Code | Terminal agent | Your machine (cloud option) | In the loop, per task |
| Codex | Terminal agent plus cloud tasks | Your machine or OpenAI’s sandbox | In the loop, per task |
| Cursor | AI-native IDE, agent inside the editor | Your machine (cloud agents too) | In the loop, per edit |
The category moves quickly and most of these now overlap at the edges — treat this as the centre of gravity of each tool, not a fixed boundary.
Working with it
You talk to Devin in the web app, in Slack, or from your IDE, and sessions can run in parallel on separate machines. It keeps a knowledge base of conventions you teach it, reusable playbooks for recurring work, and scheduled runs for jobs like dependency bumps. Output arrives as a pull request, so the usual review and CI gates still apply.
Devin is strongest on scoped, verifiable work and still needs a human reviewer on the architectural calls. Treat it as a fast junior engineer with infinite patience, not as an unsupervised one.