What is Eva
Eva is an open-source, autonomous software factory. It runs coding work end to end, from a spec a machine can check to evidence it was done.
Eva runs coding work end to end: you give it a spec a machine can check, a harness does the work, and Eva keeps the evidence that it was done.
It runs on your laptop as a CLI, and it runs as a service you reach from anywhere. Those are the same program.
Eva is early
Today Eva is a terminal client on a plugin kernel. A small core loads plugins, and every capability is one — the model, the surface, the trace, the themes. What ships today is on this site. What comes next is on the roadmap.
The problem
You have subscriptions to Claude Code, Codex, and OpenCode. Each is a good harness. None can tell you what a change cost, none can check another's work, and none can run twenty tasks overnight and show you the evidence in the morning.
Switching between them means switching tools, losing history, and starting the accounting again. And all of them are tied to the machine you are sitting at. Close the laptop and the work stops.
What Eva does about it
One contract over every harness. Eva's native harness and every foreign one implement the same interface, so a task runs on any of them without being rewritten. Eva's own harness has no privileged position.
One trace. Everything every harness does lands in one event schema. What a trace cannot rebuild is a bug.
One verifier. Acceptance criteria are checked by Eva, not claimed by the agent that did the work. A claim is never evidence.
One bill. Cost is attributed per task, per merged change, and per harness. That makes "use this harness for this kind of work" a measurement rather than a preference.
What Eva is not
Not a model. Not an IDE. Not a replacement for the harnesses you use — Eva drives them, and its own harness is one entry in the same registry.
What is an open-source autonomous software factory? defines the category these four properties belong to, and how a factory differs from a harness.