# Executing Commands

To execute a command, call the `Execute` function with a context, the store, the decider, and the command:

```go
writtenEvents, err := architecturekit.Execute(
  context.TODO(),
  store,
  acquireBook,
  AcquireBook{
    BookID: "42",
    Title:  "2001 – A Space Odyssey",
    Author: "Arthur C. Clarke",
    ISBN:   "978-0756906788",
  },
)
if err != nil {
  // ...
}
```

`Execute` reads the events of the command's subject, evolves the state from them, calls the decider, and writes the events it returns. The function returns the written events, including the fields added by the server. If the decider returns no events, nothing is written, and the function returns `nil`.

*Note that `Execute` only reads the events of the command's subject itself, not those of nested subjects.*