The megamerge rule already said not to move the working copy off the
merge. Add the positive counterpart: how to actually land work while
sitting on it — absorb, squash --into, or rebase a separate commit
beneath the merge — and reach for those over jj new or jj edit unless
told otherwise.

Assisted-by: Claude Opus 4.8 (Claude Code)

diff --git a/ai/_AGENTS.md b/ai/_AGENTS.md
index 52f876eb..94fe18de 100644
--- a/ai/_AGENTS.md
+++ b/ai/_AGENTS.md
@@ -107,6 +107,13 @@ another commit) discards that combined view, and rebuilding it means
 re-running the merge by hand. If a megamerge is present, stay on it
 unless I explicitly ask you to move.
 
+To land changes while a megamerge is checked out, keep `@` on it: make
+the edits, then fold them into the right place with `jj absorb` (routes
+each hunk to the ancestor that last touched it), `jj squash --into
+<rev>` (targets a specific branch), or `jj rebase` (inserts a separate
+commit beneath the merge). Reach for these over `jj new` or `jj edit`
+onto another commit unless I explicitly say otherwise.
+
 Commit quality:
 - Each commit should be one logical unit of change
 - Every commit must build and pass checks (bisect-able history)