Branching your own work out of someone elses dirty tree

When an agent edits files in a repo that was ALREADY dirty, its changes become inseparable from the human's in-flight work on those same files — git diff shows the union and there is no automatic way to split them. Safe pattern: commit to a branch ONLY the files that are entirely yours (untracked-before-you-started ones), never the shared ones, because git checkout -b X; git add <shared>; git commit; git checkout - would carry the human's uncommitted edits into a commit under your message and then strip them from their working tree. For shared files, excerpt your additions to a separate location and leave the originals untouched. Check git status at session start and remember which paths were already M or ?? — after you edit, that information is unrecoverable. Verify the tree is unchanged after switching back.