OSC 133 — Shell Integration (FTCS)

Sequence	OSC 133 ; <kind> [ ; <params> ] ST
Otty support	✓

Description

Marks the boundaries of prompts and commands in the byte stream. The terminal uses these marks for command outlines, jump-to-prev / next-command, exit-status indicators, and intelligent paste.

This is the "Final Term shell integration" protocol (FTCS) as adopted by iTerm2, WezTerm, Kitty, VS Code, and now Otty.

Kinds

<kind>	Emitted	Meaning
A	Just before the prompt is drawn	Prompt start
B	After the prompt, before input	Prompt end / command start (input zone)
C	When the command begins executing	Command output start
D ; <exit>	When the command finishes	Command end with exit code
L	(optional)	Marks the start of a "user input prompt" within a tool

Example

# Minimal zsh precmd / preexec:
precmd()  { print -Pn '\e]133;A\e\\'; }
preexec() { print -Pn '\e]133;C\e\\'; }
# B is emitted by zsh's prompt builder if PROMPT_SUBST is on.
# D is emitted by zsh's chpwd or via a hook — Otty's installer handles it.

In practice, Otty's otty shell install writes the snippets — you should never need to hand-roll these.

Try it

• otty features try semantic-prompt — fires the full A → B → C → D;0 sequence so you can verify prompt-detection wiring (Open Quickly history, etc.).
• otty features try error-state — same flow with D;1 plus an OSC 9;4 error badge, to confirm Otty marks errored prompts.

Related

• Shell Integration
• Outline