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Cursor color (OSC 12)
ESC ] 12 ; color BELOSC 12 sets or queries the text cursor color. To set:
ESC ] 12 ; color BEL where color is an X11 color specification. To query: ESC ] 12 ; ? BEL — the terminal responds with the current cursor color in rgb:RR/GG/BB format. Applications use this to make the cursor match their color scheme, or to provide visual feedback (e.g. changing cursor color to red in insert mode). Widely supported by xterm-compatible terminals.How this is testedautomated
Query cursor color with
Query cursor color with
OSC 12 ; ? BEL, verify response matches OSC 12 ; rgb:... pattern.The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.
Analysis2026-04-06
Supported by 6 of 14 backends (43%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |
Headless Backends
Parser correctness only — a ✓ means the parser accepts the sequence.
| Backend | Version | Support | Notes |
|---|---|---|---|
| Alacritty | 0.26.0 | ✗ no | OSC 12 cursor color query requires a real display — headless backends have no color palette to query |
| Kitty | 0.40.0 | ✗ no | OSC 12 cursor color query requires a real display — headless backends have no color palette to query |
| vt100.js | 0.2.1 | ✗ no | Not implemented — pure TypeScript emulator |
| vterm | 0.2.0 | ✗ no | OSC 12 cursor color query not implemented in vterm.js |
| WezTerm | 0.1.0-fork.5 | ✗ no | OSC 12 cursor color query requires a real display — headless backends have no color palette to query |
| xterm.js | 5.5.0 | ✗ no | OSC 12 cursor color query requires a real display — headless backends have no color palette to query |