Blockchain Tools 0.30.1 / Transactions
Transaction previews and simulation
Build an immutable transaction intent and review simulation results before any wallet prompt.
A preview begins with a reviewed callable schema and trusted contract. Tools validates the chain, contract, method, ordered inputs, capability, active wallet, and site sending policy before simulation.
The preview must show the action, ecosystem, chain, target, method, important inputs, value, estimated cost where available, warnings, and simulation status. Simulation is evidence, not a guarantee of inclusion or success.
Immutable intent
Confirmation binds to the exact previewed intent. Changing the account, chain, contract, method, arguments, value, or relevant policy invalidates the preview. Re-preview instead of reusing stale confirmation state.
A failed, unavailable, stale, or mismatched simulation blocks guarded sending. The browser must not convert a provider error into a successful preview.
Test expected success, expected revert, wrong chain, changed account, changed input, expiry, and duplicate submission on the correct test network before enabling production writes.