Devin popularised the idea of handing a ticket to an AI engineer and getting a pull request back. Last Light runs the same loop, but on your infrastructure, with your model keys, and with every step of the workflow readable and forkable.
Devin and Last Light share a lifecycle: a ticket goes in, a sandboxed agent plans and edits code, a pull request comes out, a human reviews it. If that loop is all you need, Devin is far less work. There is nothing to run.
They diverge on ownership. Devin is a product: a vendor's model, a vendor's sandbox, a vendor's idea of how the work should flow. Last Light is a harness you operate: your keys, your egress policy, your GitHub token scopes, and a workflow graph you can read and change. That is the entire trade: convenience against control.
Last Light is also broader. Devin is an issue→PR agent. Last Light additionally does scheduled triage sweeps, PR review, security review, repo-health reporting, and Slack chat, all as workflows on the same engine.
| Last Light | Devin | |
|---|---|---|
| Hosting | Self-hosted only: your host, your Docker stack | SaaS: your code runs in Cognition's cloud |
| Model choice | BYO: Anthropic, OpenAI, OpenRouter and others | Vendor model, no BYOM |
| Trigger | GitHub webhooks, Slack, cron sweeps, CLI | Task / issue assignment |
| Workflow control | YAML DAGs you fork and override in an instance/ overlay | Fixed product behaviour |
| Isolation | Docker / micro-VM sandbox with default-deny egress firewall | Vendor cloud sandbox |
| Human gates | Built-in mid-run approvals via GitHub, Slack or dashboard | Review the PR at the end |
| Scope | A suite: triage, review, build, security, health, chat | Task → PR |
| Cost | Free / MIT + your model spend + your infra | Subscription |
| Support | None. Read the source | Commercial vendor |
instance/ overlay..lastlight/ to tune models, prompts and skills for itself, read from the default branch and clamped so it can only ever be more conservative than you set.you want an autonomous engineer working today with nothing to operate, you're comfortable with your source running in a vendor's cloud on a vendor's model, and you'd rather buy the result than run the machine.
where the code runs, which model sees it, and what the agent can reach on the network are first-order requirements, and you want repo maintenance as a whole suite of forkable workflows rather than a single ticket→PR product.
The honest caveat: if you pick Last Light you are taking on operations. You provision the host, you run the stack, you keep the images current, and there is no vendor to page at 2am. That cost is real, and it only pays for itself if self-hosting is something you actually need rather than something that merely sounds better.