I use thisismy and thisismy-desktop to combine code - full repos + and specifications as Megaprompts into the LLM - mostly currently Gemini 2.5 Pro as we are talking ~500k tokens

full files, JIRA tickets with is/should, DRY/KISS refactorings and root cause analysis are done this way

full files are usually just copy/pasted, everything else added for cursor as in insttuctions