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

# Configuration

The GitHub Copilot CLI agent runtime in Mains is configured through in-app settings. These options control how the Copilot binary is located, how it communicates with the application, logging verbosity, and automatic recovery behavior.

## **Tool Permissions**

Mains exposes the Copilot SDK's hook system to give you fine-grained control over which tools the agent can use. Through the config screen you can set permission rules that run before every tool execution.

Each rule evaluates via the `onPreToolUse` hook and returns one of:

| **Decision** | **Effect**                                                |
| ------------ | --------------------------------------------------------- |
| **Allow**    | Tool executes normally                                    |
| **Deny**     | Tool is blocked; an optional reason is shown to the agent |

This lets you restrict dangerous operations — for example, blocking shell access entirely:

<Note>
  Mains handles hook lifecycle internally — you only need to configure which tools to allow or deny through the config screen.
</Note>