Execution Layer Assumptions Smart Contracts Rely On

Contracts assume all state changes within a transaction succeed or fail together. Cross-chain and cross-rollup interactions shatter this, creating systemic risk.

• MEV extraction exploits atomicity gaps between chains.
• Failed bridging transactions leave funds in limbo, requiring complex recovery.
• Partial failures in multi-step DeFi operations can liquidate users.

Contracts assume stable gas costs and immediate state finality. Shared sequencers, priority fees, and multi-chain environments make this impossible.

• Gas auctions on block builders like Flashbots create volatile, unpredictable costs.
• State latency between L2s (e.g., Arbitrum, Optimism) and L1 breaks synchronous logic.
• Pre-confirmations from entities like Espresso or Astria introduce new trust vectors.

Shift from prescribing low-level transactions to declaring desired outcomes. Let specialized solvers (e.g., UniswapX, CowSwap, Across) handle execution complexity.

• User specifies 'what' (e.g., best price for 100 ETH), not 'how'.
• Solvers compete across venues and chains, absorbing atomicity and gas risk.
• Protocols like Anoma and SUAVE formalize this paradigm, separating intent from execution.

Contracts assume a predictable gas ceiling for atomic execution. This is a system-level assumption that dictates composability and economic security.

• Key Risk: A sudden reduction (e.g., for DoS protection) can brick batched transactions and complex DeFi operations.
• Key Insight: Designs like Uniswap V3's concentrated liquidity or flash loan arbitrage paths are gas-bound. A 20% reduction in limit can cripple these mechanics.

Contracts are written as if reading/writing any storage slot has consistent cost and latency. This ignores the reality of warm/cold access and underlying database structures.

• Key Risk: Performance cliffs and unpredictable gas costs when access patterns change, breaking keeper bot economics.
• Key Insight: Protocols like Aave or Compound, with massive state footprints, are vulnerable. A 10x gas spike on critical functions during congestion can be fatal.

Rollup-native contracts (e.g., on Arbitrum, Optimism) assume the sequencer is a reliable, censorship-resistant mempool. This is a massive centralization assumption.

• Key Risk: Sequencer downtime halts L2, while malicious sequencing enables MEV theft and transaction reordering attacks.
• Key Insight: Protocols relying on sub-second finality for limit orders or oracle updates (like GMX or Perpetual DEXs) will fail. Assumes ~100% uptime from a single entity.

Contract logic often hardcodes time-based functions (e.g., 24-hour timelocks, TWAP oracles) assuming a stable block interval. This is false under extreme reorgs or chain halts.

• Key Risk: A prolonged chain reorganization or a switch to a PoS chain with variable block times (vs. PoW) can accelerate or delay critical contract state changes.
• Key Insight: This breaks DeFi primitives like Euler's loan health checks or MakerDAO's liquidation engines that depend on precise block-counting.

Contracts assume all exogenous data comes via a defined oracle (Chainlink, Pyth). This ignores MEV bots, sequencer ordering, and block builders as covert input channels.

• Key Risk: The execution layer itself leaks information. A fast bot seeing a pending large swap can front-run the oracle update, breaking DEX pricing.
• Key Insight: Naive AMM designs are exploited via this channel. Solutions like CowSwap (batch auctions) or UniswapX (off-chain intent matching) explicitly architect around it.

Contracts assume users can always bid a gas price to get included. This fails under base fee volatility and Priority Fee (Tip) auctions dominated by MEV.

• Key Risk: During network surges, user transactions are priced out, causing protocol operations (like liquidations or rebalancing) to stall unless they overpay.
• Key Insight: Protocols like MakerDAO's keeper system or Aave's liquidation bots must model gas price spikes >1000 gwei as a normal state, not an edge case.