# yaml.decode

```python
yaml.decode(content)
```

Returns the data from a single YAML document as dictionaries, lists, strings,
integers, floats, booleans, and `None`. Empty input returns `None`. Mapping keys
must be strings; duplicate keys, non-finite numbers, recursive aliases, invalid
syntax, and multiple documents fail the call.

```python
catalog = yaml.decode(fs.read_file(".atmos-git-hooks.yaml"))
for check in catalog["checks"]:
    print(check["id"], check.get("fix", False))
```

Custom tags do not execute Atmos functions or load external resources. For example,
`yaml.decode("value: !env HOME")` returns `{"value": "HOME"}`. YAML timestamps
decode to RFC 3339 strings. Ordinary aliases and merge keys are supported.

Use [`yaml.validate`](/functions/automation/yaml.validate) for syntax-only checks
that accept multiple documents and arbitrary mapping keys. Use
[`fs.read_file`](/functions/automation/fs.read_file) to read a local YAML file.