> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/dotandev/envcheck/llms.txt
> Use this file to discover all available pages before exploring further.

# Tool Validation

> Configure tool and CLI validation checks

## Overview

The `tools` section validates that required command-line tools are installed and meet version requirements. This is useful for ensuring developers have the correct versions of languages, package managers, and build tools.

## Configuration

Each tool check is defined by a `ToolCheck` struct (src/config.rs:22) with the following fields:

<ParamField path="name" type="string" required>
  The name of the tool/command to check. This should be the executable name as it appears in PATH.
</ParamField>

<ParamField path="version" type="string" optional>
  Semver version requirement (e.g., `">=18.0.0"`, `"^3.9.0"`). If omitted, only checks that the tool is installed.
</ParamField>

<ParamField path="required" type="boolean" default="true">
  Whether the tool is required. If `true`, missing or incompatible tools will cause validation to fail.
</ParamField>

## Examples

### Basic Tool Check

Check that a tool is installed without version requirements:

```yaml theme={null}
tools:
  - name: git
    required: true
```

### Version Requirements

Specify minimum versions using semver syntax:

```yaml theme={null}
tools:
  - name: node
    version: ">=18.0.0"
    required: true
  - name: npm
    version: ">=9.0.0"
    required: true
```

### Optional Tools

Mark tools as optional when they're nice-to-have but not essential:

```yaml theme={null}
tools:
  - name: docker
    required: false
  - name: kubectl
    required: false
```

## Real-World Examples

<CodeGroup>
  ```yaml Node.js Project theme={null}
  version: "1"

  tools:
    - name: node
      version: ">=18.0.0"
      required: true
    - name: npm
      version: ">=9.0.0"
      required: true
    - name: git
      required: true
  ```

  ```yaml Rust Project theme={null}
  version: "1"

  tools:
    - name: rustc
      version: ">=1.65.0"
      required: true
    - name: cargo
      required: true
  ```

  ```yaml Python/Django Project theme={null}
  version: "1"

  tools:
    - name: python
      version: ">=3.9.0"
      required: true
    - name: pip
      required: true
    - name: docker
      required: false
  ```

  ```yaml Ruby on Rails Project theme={null}
  version: "1"

  tools:
    - name: ruby
      version: ">=3.0.0"
      required: true
    - name: bundle
      required: true
    - name: node
      required: false
    - name: yarn
      required: false
  ```

  ```yaml Go Project theme={null}
  version: "1"

  tools:
    - name: go
      version: ">=1.18.0"
      required: true
  ```
</CodeGroup>

## Semver Version Syntax

The `version` field supports standard semver syntax:

| Syntax    | Meaning                                      | Example                                     |
| --------- | -------------------------------------------- | ------------------------------------------- |
| `>=X.Y.Z` | Greater than or equal to                     | `>=18.0.0`                                  |
| `^X.Y.Z`  | Compatible with (minor versions)             | `^3.9.0` allows 3.9.x, 3.10.x but not 4.0.0 |
| `~X.Y.Z`  | Approximately equivalent to (patch versions) | `~1.2.3` allows 1.2.x but not 1.3.0         |
| `X.Y.Z`   | Exact version                                | `1.65.0`                                    |

<Note>
  If the `version` field is omitted or set to `null`, envcheck will only verify that the tool is installed without checking its version.
</Note>

## Default Behavior

From the struct definition in src/config.rs:22:

* `name`: Required field, no default
* `version`: Defaults to `None` (no version check)
* `required`: Defaults to `true`

<Warning>
  When `required: true`, the validation will fail if:

  * The tool is not found in PATH
  * The tool version doesn't match the specified requirement
</Warning>