# ctx.arguments

The `ctx.arguments` value is a read-only dictionary of the positional arguments Atmos parsed for a custom command,
keyed by each argument's declared name.

## Usage

```python
ctx.arguments["name"]
```

## Returns

A frozen dictionary with sorted keys. In a custom command it has one entry for each argument the command declares, with
the value the user typed. In a workflow step, a hook, or a standalone script it is an empty dictionary. A standalone
program receives its arguments as the `args` argument of the entry function it passes to
[`cli.command`](/functions/automation/cli.command).

Steps inside `parallel` and `matrix` groups inherit the dictionary.

## Examples

### Read a declared argument

```yaml
commands:
  - name: greet
    arguments:
      - name: name
        description: Who to greet
        required: true
    steps:
      - name: greet
        type: script
        interpreter: starlark
        script: |
          print("Hello, {}!".format(ctx.arguments["name"]))
```

```shell
atmos greet Ada
```

```text
Hello, Ada!
```

### Combine arguments and flags

```python
service = ctx.arguments["service"]
replicas = int(ctx.flags["replicas"])
print("{}: {} replicas".format(service, replicas))
```

### Fail early on a missing value

```python
if not ctx.arguments.get("service"):
    fail("a service name is required")
```

## Related

- [`ctx.flags`](/functions/automation/ctx.flags) holds the parsed flags.
- [`cli.arg`](/functions/automation/cli.arg) declares arguments for a standalone script.
- [`ctx`](/functions/automation/ctx) lists every context attribute.
- [Custom commands](/automation/custom-commands)