Stability Parameter Bounded External Access Module (SP-BEAM)

A module for the Sky Protocol that enables direct changes to stability parameters (duty, dsr, ssr) through a simple, secure interface with proper constraints and timelocks.

Overview

The SP-BEAM module provides a streamlined way to modify stability parameters in the Maker Protocol, including:

• Stability fees (duty) for different collateral types via the Jug contract
• Dai Savings Rate (DSR) via the Pot contract
• Sky Savings Rate (SSR) via the sUSDS contract

Features

• Batch updates for multiple rate changes
• Two-level access control:
  • Admins can configure the module
  • Facilitators can propose and execute rate changes
• Rate change constraints:
  • Min/max caps per rate
  • Max update delta
• Event emission for all actions
• Simple, auditable implementation

Installation

forge install

Testing

forge test

Usage

1. Deploy the contract with the required addresses:

SPBEAM beam = new SPBEAM(
    jugAddress,  // For stability fees
    potAddress,  // For DSR
    susdsAddress, // For SSR
    convAddress  // For rate conversions
);

2. Configure the module parameters:

// Set timelock duration
beam.file("tau", 1 days);

// Configure constraints for a collateral type
beam.file("ETH-A", "max", 1000);  // Max rate: 10%
beam.file("ETH-A", "min", 1);     // Min rate: 0.01%
beam.file("ETH-A", "step", 100);  // Max change: 1%

// Configure constraints for DSR
beam.file("DSR", "max", 800);  // Max rate: 8%
beam.file("DSR", "min", 1);    // Min rate: 0.01%
beam.file("DSR", "step", 100); // Max change: 1%

3. Add facilitators who can propose and execute rate changes:

beam.kiss(facilitatorAddress);

4. Execute a batch of rate changes:

SPBEAM.ParamChange[] memory updates = new SPBEAM.ParamChange[](2);
updates[0] = SPBEAM.ParamChange("DSR", 75);     // Set DSR to 0.75%
updates[1] = SPBEAM.ParamChange("ETH-A", 150);  // Set ETH-A rate to 1.5%
beam.set(updates);

Security

The module implements a robust security model:

• Two-level access control (admins and facilitators)
• Rate constraints to prevent extreme changes
• Disabling without GSM delay via SPBEAMMom contract
• Circuit breaker (halt) functionality
• All actions emit events for transparency
• Batch updates must be ordered alphabetically by ID to prevent duplicates

License

AGPL-3.0-or-later