# 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.

<Callout title="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](/about/roadmap).
</Callout>

## 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?](/software-factory) defines the
category these four properties belong to, and how a factory differs from a
harness.

## Start here

<Cards>
  <Card
    title="Install"
    href="/install"
    description="Four channels, and how to verify a download."
  />
  <Card
    title="Connect a model"
    href="/connect-a-model"
    description="One key, and where it does not go."
  />
  <Card
    title="Your first run"
    href="/first-run"
    description="Ask something, read the answer, see the cost."
  />
  <Card title="Concepts" href="/concepts" description="The words Eva uses for its own machinery." />
</Cards>

## If you are an agent

Every page here is also served as markdown: append `.md` to any path, so
`/install` is also [`/install.md`](/install.md). Each page's HTML advertises its
own twin with `<link rel="alternate" type="text/markdown">`, and asking for
`Accept: text/markdown` returns the twin as well.

- [llms.txt](/llms.txt) — every page as one index, with what Eva is for and
  when to reach for it.
- [llms-full.txt](/llms-full.txt) — every page's markdown, concatenated, for
  reading the whole manual in one fetch.
- [auth.md](/auth.md) — how to obtain a credential, which is by not needing
  one. There is no Eva account and no Eva API key.
- [pricing.md](/pricing.md) — zero, and what you do pay for.
- [CLI reference](/reference/cli) — every command and every global flag.
  `eva -p "<prompt>"` is the whole scriptable surface.

A scoped index exists per area — [use](/use/llms.txt),
[configure](/configure/llms.txt), [extend](/extend/llms.txt),
[reference](/reference/llms.txt), [about](/about/llms.txt) — for taking one
area into context instead of the manual.


---

This page as HTML: https://docs.evafactory.co
Every page as one markdown index: https://docs.evafactory.co/llms.txt