Concepts

Environment

An isolated, self-contained chain state with its own accounts, assets, contracts, and network configuration. Environments are the unit of isolation: nothing in one environment is visible to another.

Snapshot

An immutable, content-addressed capture of an environment's full state at a point in time. Every environment has at least one snapshot (its genesis). Resetting to a snapshot is instantaneous and exact.

Run

A recorded execution of one or more operations against an environment, starting from a known snapshot. A run has inputs, a resulting state diff, emitted events, traces, and a status. Runs are the primary unit of inspection and reproducibility.

Scenario

A named, versioned sequence of operations and assertions. Scenarios let you describe a situation — a liquidity shock, a permission change, a reorg — once, and replay it against any compatible environment.

Operation

A single instruction inside a run or scenario: a transaction, a contract call, a deployment, a block advance, a network change, or an assertion.

Diff

The structured set of state changes produced by a run: storage writes, balance changes, nonce increments, code changes, and the events emitted alongside them. Diffs are what you inspect, compare, and reason about.