- Add P2 section to phases/phase-100/README.md - Document allowed form: s = s + x (x must be read-only) - List Fail-Fast cases (reversed ops, complex RHS, multiple updates) - Add example with numeric output 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>