> ## Documentation Index
> Fetch the complete documentation index at: https://codexceed.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# avatar-harness

> A bounded, verifiable loop around an LLM — a coding-agent harness, not a chat app.

## What this is

**avatar-harness** is the runtime *around* a language model that turns a
natural-language task into a bounded, verifiable engineering loop.

The defining inversion versus a chat app:

> The model **proposes** actions; the harness **owns** execution, state,
> permissions, logging, and verification. The loop terminates on **external
> verification**, not on a text reply from the model.

## How the loop works

Each turn, the harness assembles a compact context packet from `TaskState`, asks
the model for exactly one validated decision (a tool call, a final answer, or a
question), executes it through a path-confined `Workspace`, records the result,
and applies it back to state. A proposed "final answer" is not the end — it is a
*proposal* the `Verifier` disposes of using external evidence (tests, lint,
diff). Only the harness marks a task `success`, and only on positive signal.

## Where to go next

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/guides/quickstart">
    Install to a verifier-checked answer in five minutes.
  </Card>

  <Card title="SDK guide" icon="cubes" href="/guides/sdk">
    The curated surface: Harness, the two-plane Session, typed events, config.
  </Card>

  <Card title="Build a terminal agent" icon="terminal" href="/tutorials/terminal-agent">
    A streaming, approval-answering agent of your own in \~90 lines.
  </Card>

  <Card title="Core invariants" icon="shield-check" href="/concepts/invariants">
    The five load-bearing rules that thread through every component.
  </Card>

  <Card title="Architecture" icon="sitemap" href="/concepts/architecture">
    The component map: runner, state, tools, verifier, events.
  </Card>
</CardGroup>

<Note>
  The **API reference** tab is generated directly from the codebase's
  docstrings — it is always in sync with the source.
</Note>