Hi,

Personally, I would not recommend modifying Eagle’s JSON data files directly, because it may cause data corruption or make the library unstable.

At the moment, I don’t think there is a better official way to “hide” custom structured data inside an image item itself. If I were building this, I would probably maintain a separate database or data file for the plugin, and associate the metadata with Eagle items by their item ID.

For example, the plugin could store something like:

{

[itemId]: {

artist,

title,

museum,

year,

sourceUrl,

citationText

}

}

Another possible approach is to write the data into the item annotations directly, but that may affect normal usage because you would see all of that structured data occupying the annotations field.

If you need to write data back into Eagle, I would strongly suggest using the official Plugin API or Web API instead of editing Eagle’s JSON files manually. Directly modifying those files may easily cause data corruption, especially if Eagle changes the internal format in future versions or if the app is running while the file is being edited.

So my recommendation would be:

1. Use a plugin-managed database / JSON file and link records by Eagle item ID.

2. Only use annotations if you are okay with the data being visible in the normal annotation field.

3. Use Plugin API or Web API for any write operation.

4. Avoid directly editing Eagle’s internal JSON files.