Harden Claude create-plan with explicit sub-skill and plan-mode guards

docs/CREATE-PLAN.md

@@ -80,6 +80,24 @@ Codex must invoke these explicit commands during planning:
   - `story-tracker.md`
   - `continuation-runbook.md`
 
+## Variant Hardening Notes
+
+### Claude Code
+
+- Must invoke explicit required sub-skills:
+  - `superpowers:brainstorming`
+  - `superpowers:writing-plans`
+- Must enforce plan-mode file-write guard:
+  - if in plan mode, instruct user to exit plan mode before generating files
+- Must copy `original-plan.md` from `~/.claude/plans/` when available.
+
+### Codex
+
+- Must run explicit commands:
+  - `~/.codex/superpowers/.codex/superpowers-codex bootstrap`
+  - `~/.codex/superpowers/.codex/superpowers-codex use-skill brainstorming`
+  - `~/.codex/superpowers/.codex/superpowers-codex use-skill writing-plans`
+
 ## Execution Workflow Rules
 
 - Read runbook first.