The moderation plugin you described sounds interesting and promising. It's great to hear that you're experimenting with the OpenAI API and exploring the capabilities of a language model for moderation. Fine-tuning the model and incorporating user feedback via tooltips is a valuable approach to improving the overall moderation experience.
While the response time of several seconds may not be real-time, it's still feasible for low-traffic sites. Cost-effectiveness is also important, and it's good to know that the moderation costs are reasonable, averaging around $0.001 per moderation.
Considering your experience as a developer adjacent to your day job, it's understandable that the code may not be optimized. Nonetheless, it's impressive that you were able to implement the plugin using action filters and achieve promising results.
Overall, it seems like you're off to a good start with your moderation plugin, and it's exciting to see how further fine-tuning and potential exploration of open-source language models could enhance its capabilities.