$M Extensions Framework

M Extension Framework is a modular templates of ERC-20 stablecoin extensions that wrap the yield-bearing $M token into non-rebasing variants for improved composability within DeFi. Each extension manages yield distribution differently and integrates with a central SwapFacility contract that acts as the exclusive entry point for wrapping and unwrapping.

All contracts are deployed behind transparent upgradeable proxies (by default).

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🧩 M Extensions

Each extension inherits from the abstract MExtension base contract, which defines shared wrapping logic. Only the SwapFacility is authorized to call wrap() and unwrap(). Yield is accrued based on the locked $M balance within each extension and minted via dedicated yield claim functions.

In-Scope Extensions

• MYieldToOne

  • All yield goes to a single configurable yieldRecipient
  • Includes a blacklist enforced on all user actions
  • Handles loss of $M earner status gracefully

• MEarnerManager

  • Redistributes yield to all holders minus per-address feeRate
  • Enforces a whitelist; non-whitelisted users are frozen and yield is redirected as fee
  • Yield is claimed via claimFor(address)
  • Does not handle loss of $M earner status, leading to potential insolvency if not upgraded

• MYieldFee

  • All users receive the same yield rate, discounted by a global feeRate
  • Yield can be redirected via claimRecipient per user
  • Includes updateIndex() to resync with new $M rates
  • Can handle loss and regain of $M earning status via disableEarning() and enableEarning()

• MSpokeYieldFee

  • Optimized for EVM sidechains (e.g., Arbitrum, Optimism)
  • Index updates occur via bridging, not time-based growth
  • Uses an external rateOracle for fee calculation
  • Inherits most behavior from MYieldFee

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🔁 SwapFacility

The SwapFacility contract acts as the exclusive router for all wrapping and swapping operations involving $M and its extensions.

Key Functions

• swap() – Switch between extensions by unwrapping and re-wrapping
• swapInM(), swapInMWithPermit() – Accept $M and wrap into the selected extension
• swapOutM() – Unwrap to $M (restricted to whitelisted addresses only)

All actions are subject to the rules defined by each extension (e.g., blacklists, whitelists)

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💱 UniswapV3SwapAdapter

A helper contract that enables token swaps via Uniswap V3.

• Immutable and admin-controlled
• Uses Uniswap's SwapRouter02
• Functions:
  • swapIn(path, ...)
  • swapOut(path, ...)
• Supports multi-hop paths or single-hop with default 0.01% fee
• Token whitelist is controlled via DEFAULT_ADMIN_ROLE

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