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

# GPv2AllowListAuthentication

> Solver authorization contract managing the allowlist-based access control system

# GPv2AllowListAuthentication Contract

The `GPv2AllowListAuthentication` contract manages solver authorization for CoW Protocol settlements through an allowlist-based access control system.

## Architecture

The contract employs a two-tier access model:

* **Manager** - Handles day-to-day solver administration
* **Proxy Owner** - Top-level administrator with override capabilities

## State Variables

| Variable  | Type                       | Description                                          |
| --------- | -------------------------- | ---------------------------------------------------- |
| `manager` | `address`                  | Address with permissions to add/remove solvers       |
| `solvers` | `mapping(address => bool)` | Private mapping tracking authorized solver addresses |

## Functions

### initializeManager()

One-time initialization for proxy deployment:

```solidity theme={null}
function initializeManager(address manager_) external initializer {
    manager = manager_;
    emit ManagerChanged(manager_);
}
```

### setManager()

Transfers the manager role. Can be called by the current manager or proxy owner:

```solidity theme={null}
function setManager(address manager_) external onlyManagerOrOwner {
    manager = manager_;
    emit ManagerChanged(manager_);
}
```

### addSolver()

Grants solver authorization (manager only):

```solidity theme={null}
function addSolver(address solver) external onlyManager {
    solvers[solver] = true;
    emit SolverAdded(solver);
}
```

### removeSolver()

Revokes solver authorization (manager only):

```solidity theme={null}
function removeSolver(address solver) external onlyManager {
    solvers[solver] = false;
    emit SolverRemoved(solver);
}
```

### isSolver()

Checks solver authorization status (public view):

```solidity theme={null}
function isSolver(address solver) external view returns (bool) {
    return solvers[solver];
}
```

## Access Control Modifiers

| Modifier             | Allowed Callers              |
| -------------------- | ---------------------------- |
| `onlyManager`        | Current manager address only |
| `onlyManagerOrOwner` | Manager or proxy admin       |

## Events

```solidity theme={null}
event ManagerChanged(address newManager);
event SolverAdded(address solver);
event SolverRemoved(address solver);
```

## Proxy Integration

The contract supports EIP-1967 compliant proxies, enabling:

* Upgradeability of the authentication logic
* Emergency governance override through proxy admin
* Consistent address across upgrades