Improvement: Make all parts of the prompt visible and configurable

[saladpanda]

Is your feature request related to a problem? Please describe.
While trying to optimize the prompt for best results i noticed that several hardcoded parts are added to the promt.
Examples:

• https://github.com/clusterzx/paperless-ai/blob/main/config/config.js#L62
• https://github.com/clusterzx/paperless-ai/blob/main/config/config.js#L77
• https://github.com/clusterzx/paperless-ai/blob/main/services/openaiService.js#L125
• https://github.com/clusterzx/paperless-ai/blob/main/services/openaiService.js#L138
• https://github.com/clusterzx/paperless-ai/blob/main/services/openaiService.js#L151
• https://github.com/clusterzx/paperless-ai/blob/main/services/openaiService.js#L261

It is not obvious to a user what exactly gets sent to the AI and therefore hard to adjust the prompt for the desired results.
E.g. I want to tell the AI to limit itself to only the preexisting tags. Knowing that they are prependet to the prompt here would have helped with this.

Further, these hardcoded elements are in english. I wanted to try whether a german prompt would give me better results, but the hardcoded parts will still remain english.

Describe the solution you'd like
I suggest making the full prompt configurable on the settings page.
Consider introducing variables for "preexisting tags" and "preexisting correspondents" similar to what paperless-gpt uses:
https://github.com/icereed/paperless-gpt?tab=readme-ov-file#custom-prompt-templates

For the part explaining the JSON output format to the AI you could use a separate box that only becomes editable when the user confirms they know what they are doing because this format is important for the implementation.

Describe alternatives you've considered

• I could edit the hardcoded prompt elements in the code and build my own docker container, but that wouldn't help others.

[clusterzx]

If you do this it will open the door to hell for issues here in the repo. So many users are already overwhelmed with the pre-existing options.

I wont imagine what will happen if you let the user full control over the JSON structure.

[saladpanda]

Agreed regarding the JSON structure :-D.

But I still think it would be benefitial to make the other hardcoded parts configurable.
And adding a notice to the settings page about what exactly gets added to the prompt would be helpful as well.