Takeaway: I'd start the next prompt by giving it the exact gh pr create body as a file from the start, since inline multi-line strings with backticks in bash keep breaking the command.
Takeaway: Next time I'd start the prompt by pointing straight at format-cells.ts and the multi-range support so the agent doesn't have to rediscover it through grep.
Takeaway: Next time I'd point straight at Pi's own compaction implementation as the reference from the start, since checking 'what does Pi do' twice (for token budgeting and for the temperature/reasoning conflict) was what actually resolved both the context % bug and the mysterious /compact 400 error.