# atmos config set

Set a value in your `atmos.yaml` configuration using a dot-notation path. The edit
preserves comments, anchors/aliases, Atmos YAML functions, and Go templates.

## Usage

```shell
atmos config set <path> <value> [--type <type>]
```

By default (`--type=auto`) the value's type is inferred in order: first from
the Atmos config schema when `<path>` matches a known field (`mcp.enabled` writes
a boolean, `settings.terminal.max_width` writes an int, and so on); otherwise from
the type of the value already at `<path>` (a `true`/`false` already there infers
bool, a bare number infers int/float); otherwise from the new value's own shape
(`5` infers int, `true` infers bool, `3.14` infers float). Only when none of those
have an answer — the value doesn't even look like a bool/int/float, e.g. a plain
word for a brand-new `vars` path — does it fall back to writing a string, and
Atmos prints a warning in that case since the fallback is easy to miss. Pass
`--type` explicitly to skip inference entirely.

## Examples

```shell
# Type inferred from the schema -- writes a boolean, not the string "true".
atmos config set mcp.enabled true
atmos config set components.terraform.apply_auto_approve true

# Type inferred from the existing value at the path (no schema entry needed).
atmos config set vars.replicas 5

# Type inferred from the new value's own shape -- vars.debug_enabled has no
# schema entry and no existing value, but "true" looks like a bool, so it's
# written as one, not the literal string "true".
atmos config set vars.debug_enabled true

# String value (the fallback when nothing above has an answer -- Atmos warns
# here since "nan" looks like it could be numeric but can't be written as a
# float safely, so it's stored as the literal string instead).
atmos config set vars.threshold nan

# Explicit --type overrides inference.
atmos config set --type=string logs.level Debug
atmos config set --type=int settings.terminal.max_width 120

# Raw YAML literal (lists, maps).
atmos config set --type=yaml 'logs.exclude' '["a", "b"]'

# Target a specific file.
atmos config set logs.level Trace --config ./atmos.yaml
```

## Arguments

- **`<path>` (required)**
  Dot-notation path to the value (e.g. 
  `logs.level`
  ).
- **`<value>` (required)**
  The value to set. Interpreted according to 
  `--type`
  .

## Flags

- **`--type` (string, default: `auto`)**
  How to interpret 
  `<value>`
  : 
  `auto`
   (infer from the schema, then from the existing value at the path, then from the new value's own shape, falling back to string), 
  `string`
  , 
  `int`
  , 
  `bool`
  , 
  `float`
  , 
  `null`
  , or 
  `yaml`
   (a raw YAML/yq literal inserted verbatim).
- **`--config` (string slice, inherited)**
  Target a specific 
  `atmos.yaml`
   file instead of the one discovered in the current directory or git root. Must name exactly one file: 
  `config set`
   edits a single concrete file on disk, so passing more than one 
  `--config`
   value is rejected as ambiguous.

:::note
Edits that would alter or expand a YAML anchor or alias (including changing a value
shared by an anchor) are rejected to avoid silently mutating shared data, as are
multi-document YAML files and files that define the same anchor name more than once.
Comments, anchors, indentation width, and line endings (CRLF/LF) are preserved, but
blank lines between entries are dropped and non-indented sequence styles are
normalized when a file is edited.
:::