# Validate scenes and scripts

Check saved scenes without switching tabs and repair scripts from compiler diagnostics.

Check a scene on disk while keeping another scene's unsaved edits in the editor:

```bash
swallowtail scene validate --path res://levels/arena.tscn
```

The result names `scene_path`, sets `source` to `disk`, and returns `valid`,
`issue_count`, and `issues`. Validation reads the saved scene, including inherited
scenes and nested instances. It checks external dependencies, stored node paths,
animation track targets, and missing node classes without opening the scene or
running its node scripts.

Saved validation excludes unsaved changes and absolute paths that need a runtime
tree. Omit `--path` to check the active editor scene instead:

```bash
swallowtail scene validate
```

## Read compiler diagnostics

```bash
swallowtail script validate --path res://scripts/score.gd
```

A GDScript compile failure returns `valid: false` and a `diagnostics` array. For
example, a reference to an undeclared identifier on line 3 reports:

```json
{
  "file": "res://scripts/score.gd",
  "line": 3,
  "severity": "error",
  "message": "Parse Error: Identifier \"missing_score\" not declared in the current scope."
}
```

Use the file and line to locate the repair, then validate again. Dependency errors
keep their own file attribution. Relative preloads resolve from the script's
directory. The compile check leaves the editor's error buffer available to read.

Structured GDScript diagnostics require Godot 4.5+. On older supported engines,
`diagnostics_available` is `false`; the compile verdict and error code remain
available. [C# validation](https://regiellis.github.io/godot-mcp-go/docs/csharp) uses the project's build diagnostics.

## Check several scripts

Choose exactly one validation mode:

| Mode | Scope |
| --- | --- |
| `--path res://scripts/score.gd` | One script |
| `--modified` | Modified or untracked GDScript files in a Git project |
| `--all` | Project GDScript files, excluding addons and hidden directories |

Batch results include checked, passed, and failed counts. The `results` array
lists failures with their diagnostics. An MCP client can request
[progress and cancellation](https://regiellis.github.io/godot-mcp-go/docs/mcp-setup#progress-and-cancellation) while a
batch runs.

A validation command can return a successful transport response with
`valid: false` or a nonzero `failed` count. Automation must check those fields.
For a process whose exit code tracks compile failures without an open editor,
use the [cold `check` command](https://regiellis.github.io/godot-mcp-go/docs/automation).