# Commands that interact with types
The main type inspector in Nu is the `describe` command that
takes any data type on input and reports its type signature.
E.g.
```nu
[foo bar baz] | describe
# => list<string>
```
## Commands
- `describe`
- `inspect`
- `help`
- `into (subcommands)`
- The into commands are used to cast one type into another.
- `ast`
- In the branches of abstract syntax tree that describe the type of some element