Use the protocol’s actual pricing function
Constant-product, concentrated-liquidity, and stable-swap designs produce different price impact. Calculate integer token amounts, pool fees, tick crossings, and every hop. Token decimals, wrappers, transfer behavior, and route order can materially change output.
The intended trade size should be simulated through the complete route. Tiny indicative quotes should not determine position size. Require a minimum output and conservative profit after gas, then expire the route quickly when state changes.
Understand atomicity and its limits
A contract can execute several swaps and repayments in one transaction so all state changes succeed or revert together. This reduces mismatched onchain legs. It does not guarantee inclusion, prevent copying, or remove the cost of a failed attempt.
Contract logic needs strict access control, callback validation, approved protocol and token lists, value limits, and pause capability. The signer should validate decoded instructions rather than trusting a route label or opaque calldata generated by an unconstrained process.
Model gas and transaction ordering
Estimate gas use from the exact call and test several fee scenarios. Include failed and displaced attempts in long-run cost. During congestion, the rational output may be to decline the route rather than bid away the edge.
Public transaction visibility can invite copying, reordering, or sandwich behavior. Private channels can change visibility and inclusion dynamics but introduce their own trust assumptions. Submission policy should be explicit and measured by realized outcome.
Review token, protocol, and bridge risk
Fee-on-transfer, rebasing, pausable, blacklisted, upgradeable, or malicious tokens can break generic routing assumptions. Integrations should use verified identities and known behavior. Program or contract upgrades trigger review and, when necessary, quarantine.
Bridges are usually asynchronous, so a cross-chain route is not fully atomic. Pre-funded inventory on each chain can support local execution while bridging handles rebalancing. The bridge claim, finality, and destination liquidity remain separate exposures.
Reconcile confirmed outcomes
Record detection, state reference, simulation, signed transaction, submission channel, confirmation, outputs, gas, revert reason, and final balances. Compare expected state with confirmed state and count failed transactions in strategy economics.
Security review and key isolation are prerequisites, not optimizations. Onchain composability expands the route graph, while controls should narrow which edges the system is allowed to use.