Terminal Protocol Modes Reference

Mode identifiers declared by AnsiMode and DecPrivateMode. These are wire parameters, not packed-state bit positions. Their presence in this module does not authorize a host action or guarantee an encoding path. Consult the feature map for support status, the core contract for state semantics, and the input contract for reports.

CSI denotes the control-sequence introducer, commonly transmitted as ESC [.

1. Standard ANSI Modes

CSI Pn h sets an ANSI mode; CSI Pn l resets it.

Constant	Value	Meaning
`INSERT`	`4`	Insert characters at the cursor rather than overwrite.
`NEW_LINE`	`20`	Line feeds also return the cursor to the first column.

2. DEC Private Modes

CSI ? Pn h sets a DEC private mode; CSI ? Pn l resets it.

Cursor & Display Settings

Constant	Value	Meaning
`APPLICATION_CURSOR_KEYS`	`1`	Select application cursor-key sequences.
`REVERSE_VIDEO`	`5`	Select reverse display presentation.
`ORIGIN`	`6`	Address the cursor relative to active margins.
`AUTO_WRAP`	`7`	Enable automatic line wrapping at the right margin.
`CURSOR_BLINK`	`12`	Request a blinking cursor.
`CURSOR_VISIBLE`	`25`	Show the cursor.
`REVERSE_WRAP`	`45`	With auto-wrap, move left across soft-wrapped rows.
`REVERSE_WRAP_EXTENDED`	`1045`	With auto-wrap, move left across hard breaks and cycle at the top margin.
`APPLICATION_KEYPAD`	`66`	Select application numeric-keypad sequences.
`BACKARROW_KEY`	`67`	Backspace sends BS when set and DEL when reset.

Margins & Buffers

Constant	Value	Meaning
`DECCOLM`	`3`	Select 132 columns when set, 80 when reset.
`LEFT_RIGHT_MARGIN`	`69`	Enable left/right margin controls (DECSLRM).
`ALT_SCREEN`	`47`	Switch primary/alternate screens without clearing or saving the cursor.
`ALT_SCREEN_BUFFER`	`1047`	Enter a cleared alternate screen; exit without restoring a saved cursor.
`SAVE_RESTORE_CURSOR`	`1048`	Save cursor state on set, restore it on reset.
`ALT_SCREEN_SAVE_CURSOR`	`1049`	Save the primary cursor and enter a cleared alternate screen; restore on exit.

The core lifecycle contract describes repeated switches, cursor presentation, and alternate content retention. DECCOLM also clears and resets state; it is not a general-purpose resize API.

Mouse Tracking & Reporting

Tracking modes select which events are reported; encoding modes select their wire format. They are independent selections.

Constant	Value	Meaning
`MOUSE_X10`	`9`	Button presses only.
`MOUSE_NORMAL`	`1000`	Button press/release and wheel events.
`MOUSE_BUTTON_EVENT`	`1002`	Normal tracking plus motion with a button held.
`MOUSE_ANY_EVENT`	`1003`	Normal tracking plus motion, including hover.
`FOCUS_REPORTING`	`1004`	Focus gain/loss reports.
`MOUSE_UTF8`	`1005`	UTF-8 extended mouse coordinates.
`MOUSE_SGR`	`1006`	SGR decimal reports with cell coordinates.
`ALTERNATE_SCROLL`	`1007`	Alternate-screen wheel-to-cursor-key scrolling.
`MOUSE_URXVT`	`1015`	urxvt decimal mouse reports.
`MOUSE_SGR_PIXELS`	`1016`	SGR decimal reports with pixel coordinates.

The mouse contract defines coordinate bounds and admission. Encoding vocabulary does not imply that every encoding is enabled by the encoder's policy.

Modern Enhancements

Constant	Value	Meaning
`BRACKETED_PASTE`	`2004`	Surround a paste with `CSI 200 ~` and `CSI 201 ~`.
`BELL_IS_URGENT`	`1042`	Request host attention on BEL.
`POP_ON_BELL`	`1043`	Request that the host raise its window on BEL.
`SYNCHRONIZED_OUTPUT`	`2026`	Hold render publication while a group of updates is applied.
`GRAPHEME_CLUSTER`	`2027`	Process extended grapheme clusters as terminal cells.
`COLOR_SCHEME_REPORTING`	`2031`	Subscribe to host color-scheme reports (`CSI ?997;Ps n`).
`IN_BAND_RESIZE_REPORTING`	`2048`	Subscribe to text-area size reports (`CSI 48;rows;columns;heightPixels;widthPixels t`).

Bracketed paste lets applications distinguish pasted text from typed input; the markers do not enforce application behavior or prevent execution. Synchronized output continues parsing and grid mutation; the session controls publication and releases a held frame on reset or timeout.

Change-report subscriptions use terminal-response permission. Mode 2031 reports host palette changes rather than application OSC color changes. Every enable request for mode 2048 immediately reports the current size. See the change-report contract for ordering, reset, and pixel-dimension rules.

3. Mode Status and Host Capabilities

TerminalModeStatus defines the DECRPM status parameter:

Constant	Value	Meaning
`UNRECOGNIZED`	`0`	No supported status report for this mode.
`SET`	`1`	Currently set.
`RESET`	`2`	Currently reset.
`PERMANENTLY_SET`	`3`	Fixed in the set state.
`PERMANENTLY_RESET`	`4`	Fixed in the reset state.

TerminalHostModeCapability.URGENT_BELL (2) and POP_ON_BELL (4) describe host actions available to status reporting; ALL is their combined mask (6). A host can expose a capability while denying an individual request. These bits are neither DEC mode numbers nor policy permissions.

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