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modifyOtherKeys
modifyOtherKeys (CSI > 4 ; Pv m) enables extended key reporting that distinguishes modified key combinations that would otherwise be ambiguous. At level 2, keys like Ctrl+I are reported distinctly from Tab, and Ctrl+M from Enter.
How this is tested: Check if the terminal supports xterm modifyOtherKeys mode for enhanced key reporting.
Analysis2026-03-26
Supported by 7 of 8 terminals (88%). Not supported by: Cursor. Part of the Modern TUI baseline.
Supported by 10 of 13 backends (77%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | 1.112.0 | ✓ yes | |
| Warp | 0.2026.03.18.08.24.03 | ✓ yes | |
| Cursor | 2.6.21 | ✓ yes | |
| tmux | 3.6a | ✓ yes | |
| Kitty | 0.46.2 | ✓ yes | modifyOtherKeys not exposed via Python batch bridge |
| Terminal.app | 2.15 | ✓ yes | |
| GNU Screen | 5.0.1 | ✓ yes |
Headless Backends
Parser correctness only — a ✓ means the parser accepts the sequence.
| Backend | Version | Support | Notes |
|---|---|---|---|
| vterm | 0.2.0 | ✓ yes | |
| Alacritty | 0.26.0 | ~ partial | modifyOtherKeys not exposed via alacritty_terminal API |
| WezTerm | 0.1.0-fork.5 | ~ partial | modifyOtherKeys not exposed via wezterm-term API |
| vt100 | 0.2.1 | ✗ no | Not implemented — pure TypeScript emulator |