diff --git a/CLAUDE.md b/CLAUDE.md
index 994920d3d..577458965 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -103,6 +103,9 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
   the running app). See `docs/mcp.md`. Quick non-UI checks: `lightcraft-cli render in.jpg -o out.jpg --set light.exposure=1`.
 - Export goes through `lightcraft_engine::export` (one encoder for app, CLI, MCP and web); UI-only commands live in
   `crates/ui-egui/src/menus.rs`.
+- Text boxes use `crates/ui-egui/src/text_field.rs` (`TextField`), not `egui::TextEdit`: it gives every field the
+  Cut / Copy / Paste / Select All menu, Esc restoring the text, and reports how an edit ended. Give each a widget id
+  that is unique on screen. Older fields still on `TextEdit` move over as they are touched.
 - Shell gotcha: `mv`/`cp` are aliased interactive here — use `/bin/mv -f` / `/bin/cp -f`.
 - Parallel agents: separate git worktrees and `CARGO_TARGET_DIR=target/agent-<name>`; each agent uses its **own control port** (pick one in 18000–19999, never the default 7980) and its own scratch subfolder (`<scratch>/<agent-name>/`) — never `rm -rf` shared paths; delete your target dir when done (disk is shared); keep every `Cargo.toml` valid at all times (the `crates/*` glob means one broken manifest breaks everyone).
 - Test corpora: `cargo xtask corpus --download` into `corpus/` (gitignored, CC0 only). Never commit media.