# atmos

The `atmos` step type runs an Atmos CLI command from inside a custom command or workflow, giving your automation direct access to the same stack-aware commands you run by hand. It is the default command step type when a step has `command` and no explicit `type`.

```yaml
steps:
  - name: plan
    type: atmos
    command: terraform plan vpc
    stack: tenant1-ue2-dev
```

## Fields

- **`command`**
  Required. Atmos command arguments to run, without the leading 
  `atmos`
   binary name.
- **`stack`**
  Optional stack value. Atmos appends it as 
  `-s`
   when the command does not already include a stack flag.
- **`working_directory`**
  Optional working directory for the command. See 
  [working_directory](/workflows/steps/working-directory)
  .
- **`env`**
  Optional environment variables for this step. See 
  [env](/workflows/steps/env)
  .
- **`output`**
  Optional output mode. See 
  [output](/workflows/steps/output)
  .

The step result stores stdout as the step value and includes `stdout`, `stderr`, and `exit_code` metadata.