# E4212

Compiler diagnostic name: `invalid_moon_mod_config`.

Invalid configuration in `moon.mod.json`.

`moon.mod.json` accepts only module-level configuration fields understood by the
build system. Unknown or misplaced configuration keys are rejected so that
spelling mistakes do not silently change how a module is built.

## Erroneous example

```json
{"name": "moonbit-community/example", "invalid-config": true}
```

The `invalid-config` field is not a valid module configuration key.

## Suggestion

Remove the invalid field, or move package-level configuration to `moon.pkg`.

```json
{"name": "moonbit-community/example"}
```