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

# Solution

> Solution documentation for Harbor.

The **`solution/`** folder is **optional**. It holds a reference script used by the oracle agent to sanity-check that a task is solvable. Solutions often help when debugging tasks or sandbox integrations.

## Required script

| OS      | File                 |
| ------- | -------------------- |
| Linux   | `solution/solve.sh`  |
| Windows | `solution/solve.bat` |

Harbor chooses the extension from `[environment].os` in [task.toml](/core-concepts/tasks/configuration).

Additional files (scripts, data) are allowed. At runtime Harbor copies the folder to `/solution` and runs the solve script from the task working directory.

## When to include a solution

* **Recommended** while authoring tasks — run `harbor run` with the Oracle agent to verify the task is solvable.
* **Optional** for published benchmarks — omit if you do not want a public reference implementation.

Without `solution/`, the Oracle agent cannot run.

## Configuration

```toml title="task.toml" theme={"system"}
[solution]
env = { API_KEY = "sk-test-123" }
```

Variables are applied when the Oracle executes `solve.sh`.