> For the complete documentation index, see [llms.txt](https://boxlang.ortusbooks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://boxlang.ortusbooks.com/getting-started/agentic-development/validate-your-code.md).

# Validate Your Code

Use boxlang check so AI agents can validate BoxLang and CFML syntax without executing code, and install the skill that teaches them how.

Agents write code quickly, and some of it will not parse. The `boxlang check` command gives your agent a fast, safe way to find out. It parses BoxLang and CFML source files and reports syntax errors **without executing the code or compiling it**. It is the BoxLang equivalent of `bash -n` or `node --check`.

Because it uses the same parsers as the runtime, a file that fails `boxlang check` will fail at runtime.

## 🔁 The Agent Loop

```mermaid
flowchart LR
    Edit[Edit code] --> Check[boxlang check]
    Check -->|exit 1| Fix[Read line and column, fix]
    Fix --> Check
    Check -->|exit 0| Test[Run tests]
    Test --> Done[Commit]
```

1. The agent edits or creates a file.
2. It runs `boxlang check` on the file or directory.
3. On exit code `1`, it reads the line, column, and message, fixes the file, and checks again.
4. On exit code `0`, it moves on to tests.

## ⚡ Commands

Check specific files:

```bash
boxlang check models/User.bx handlers/Main.bx
```

Check a directory recursively:

```bash
boxlang check --source ./src
```

Print only failures:

```bash
boxlang check --source ./src --quiet
```

Get machine-readable output for an agent or tool to parse:

```bash
boxlang check --source ./src --format json
```

| Option                  | Description                                                     |
| ----------------------- | --------------------------------------------------------------- |
| `--source <PATH>`       | File or directory to check. Directories are scanned recursively |
| `--format <text\|json>` | Output format. Default is `text`                                |
| `-q, --quiet`           | Suppress success output. Failures are always shown              |

Supported files: `.bx`, `.bxs`, `.bxm`, `.cfc`, `.cfm`, `.cfs`.

Exit code `0` means every file is valid. Exit code `1` means at least one file has a syntax error or the command was used incorrectly.

See the full [BoxLang Syntax Check](/getting-started/ide-tooling/boxlang-syntax-check.md) reference.

## 🎨 Pair It With the Formatter

Syntax and style are separate checks:

```bash
boxlang check --source ./src
boxlang format --check --source ./src
```

`boxlang format --check` exits non-zero when formatting drift exists. See the [BoxLang Formatter](/getting-started/ide-tooling/boxlang-formatter.md).

## 🧠 Install the Skill

The `boxlang-syntax-check` skill teaches your agent the command, the options, how to read the output, and the fix loop above.

```bash
npx skills add ortus-boxlang/skills/boxlang-developer/syntax-check
```

It is also included when you install the whole BoxLang developer set:

```bash
npx skills add ortus-boxlang/skills/boxlang-developer
```

See [Skills & Guidelines](/getting-started/agentic-development/skills-and-guidelines.md) for more.

## 📄 Tell the Agent in AGENTS.md

Skills are found when relevant, but a project rule makes it reliable:

```markdown
## Validation

After every edit to a `.bx`, `.bxs`, `.bxm`, or `.cfc` file, run `boxlang check <file>`.
Before finishing, run `boxlang check --source ./src` and `boxlang format --check --source ./src`.
Fix all reported errors before running tests.
```

## 🚦 Enforce It Automatically

A git pre-commit hook:

```bash
#!/usr/bin/env bash
boxlang check --source ./src --quiet || {
  echo "Syntax errors found. Commit aborted."
  exit 1
}
```

A CI step, before your tests:

```yaml
- name: Syntax check
  run: boxlang check --source ./src
```

{% hint style="info" %}
`boxlang check` validates syntax only. It cannot catch runtime errors, wrong arguments, or failing logic. Always run your tests too.
{% endhint %}


---

# Agent Instructions
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## Querying This Documentation
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```
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```

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