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Mode Report (DECRPM)
ESC [ ? mode $ pDECRPM (CSI ? Pd $ p) queries whether the terminal recognizes and has enabled a specific DEC private mode. The response CSI ? Pd ; Ps $ y reports the mode state: 1=set, 2=reset, 0=not recognized. Essential for feature detection.
Analysis2026-03-26
Supported by 5 of 8 terminals (63%). Not supported by: Kitty, Terminal.app, Warp. Part of the Modern TUI baseline. Notes: Kitty: Headless mode has no output stream for DECRPM responses.
Supported by 5 of 13 backends (38%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | DECAWM is set |
| Ghostty | 1.3.1 | ✓ yes | DECAWM is set |
| VS Code | 1.112.0 | ✓ yes | DECAWM is set |
| Cursor | 2.6.21 | ✓ yes | DECAWM is set |
| Warp | 0.2026.03.18.08.24.03 | ✗ no | No DECRPM response |
| tmux | 3.6a | ✗ no | tmux intercepts DECRPM — responds for its own modes, not the outer terminal |
| Kitty | 0.46.2 | ✗ no | Headless mode has no output stream for DECRPM responses |
| Terminal.app | 2.15 | ✗ no | No DECRPM response |
| GNU Screen | 5.0.1 | ✗ no | Screen does not support DECRPM (mode reporting) |
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 | Headless mode has no output stream for DECRPM responses |
| WezTerm | 0.1.0-fork.5 | ~ partial | Headless mode has no output stream for DECRPM responses |
| vt100 | 0.2.1 | ✗ no | No output stream — pure TypeScript emulator |