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Device status report (DSR 5)
ESC [ 5 nDSR 5 queries the terminal's operational status. The query is
ESC [ 5 n. The terminal responds with ESC [ 0 n to indicate it is functioning normally. This is a basic health check that also serves as a synchronization point — applications can send DSR 5 and wait for the response to ensure all previous output has been processed.How this is testedautomated
Send
Send
\x1b[5n (DSR 5), verify response contains 0n (device OK).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 all 12 tested terminals — universal adoption. Part of the Modern TUI baseline.
Supported by 10 of 14 backends (71%)
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 |
|---|---|---|---|
| vt100.js | 0.2.1 | ✓ yes | No output stream — pure TypeScript emulator |
| vterm | 0.2.0 | ✓ yes | |
| Alacritty | 0.26.0 | ~ partial | Headless mode has no output stream for DSR responses |
| Kitty | 0.40.0 | ~ partial | Headless mode has no output stream for DSR responses |
| WezTerm | 0.1.0-fork.5 | ~ partial | Headless mode has no output stream for DSR responses |
| xterm.js | 5.5.0 | ~ partial | Headless mode has no output stream for DSR responses |