Hi, I’m Troy. I build open-source tools in R. My agent harness, corteza, scored 98.6% on ARC-AGI-3’s 25 public games with Claude Opus 5 at xhigh, completing all 183 levels. The harness writes and reuses functions in a persistent R workspace. Functions and data survive conversation compaction. I wrote up the results, failures, and fixes: https://cornball.ai/posts/corteza-arc-agi-3/ #Introduction #rstats #AI