Update INV Price Feed to Dynamic-Fee INV/WETH Curve Oracle

Forum Post: https://forum.inverse.finance/t/update-the-inv-price-feed-2/628

Summary

This proposal updates the INV/USD price feed used by FiRM and Frontier to:

1. Migrate from the current INV/WETH Curve pool to the new higher-fee INV/WETH Curve pool; and
2. Replace the existing ChainlinkCurve2CoinsFeed with a new DynamicFeeCurveFeed that explicitly accounts for the Curve pool’s trading fee.

The goal is for FiRM and Frontier to use a price that reflects INV’s net-of-fee executable value in our main liquidity pool.

Background

• INV is currently priced via a Chainlink + Curve oracle:
  • Chainlink WETH/USD price, combined with
  • Curve INV/WETH twocrypto-ng EMA (price_oracle()).
• The DAO is migrating INV liquidity and routing to a new INV/WETH Curve pool configured with a higher trading fee.
• With the higher fee, the mid-price from the pool (EMA) overstates the value a liquidator can actually realize after paying fees.

To keep the oracle aligned with where INV trades and make pricing slightly more conservative, we introduce a dynamic-fee-aware variant.

DynamicFeeCurveFeed Overview

The new oracle contract, DynamicFeeCurveFeed, keeps the same basic structure:

• Uses IChainlinkBasePriceFeed for WETH → USD (18 decimals).
• Uses the new INV/WETH Curve pool for:
  • price_oracle() (EMA of the INV/WETH rate), and
  • fee() (dynamic pool fee, 1e10 precision).
• Returns INV/USD with 18 decimals and description INV / USD.

Price calculation (simplified):

• Get pairedTokenToUsdPrice (WETH/USD) from Chainlink.
• Get crvOraclePrice from curvePool.price_oracle(), which is WETH/INV
• Compute INV/USD
• Fetch fee = curvePool.fee(), clamp it to maxFee (initially 2%, equal to the pools maximum fee).
• Apply the discount: usdPrice = usdPrice * (1 - fee).

This makes the oracle reflect a post-fee price, bounded by a governance-controlled maxFee (0–100%).

The contract also includes a simple gov / pendingGov pattern and a setMaxFee(int _maxFee) function restricted to gov.

Rationale

• We are already relying on the INV/WETH Curve pool as the main liquidity venue for INV.
• With the new pool’s higher fee, using a pure mid-price (price_oracle()) overestimates the value available to liquidators and arbitrageurs.
• Applying the Curve fee in the oracle:
  • Keeps assumptions closer to real execution, and
  • Introduces a small, bounded conservative bias that improves risk management for FiRM and Frontier.

On-Chain Actions

• Update FiRM INV Feed
• Update Frontier INV Feed
• Update sINV price feed