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CodeShellManager Shell Integration

Programs running inside a CodeShellManager terminal can push session state up to the host UI by emitting a custom OSC (Operating System Command) escape sequence. This is the recommended way for tools like SSH overlays, REPLs, and TUI apps to keep CSM's accent color, git status, and tab title in sync with whatever the program actually represents — even when CSM cannot inspect that state locally.

Wire format

ESC ] 9001 ; key=value ; key=value … ST
  • ESC is \x1b (0o33, 27).
  • 9001 is the CSM-namespaced OSC identifier.
  • ST ("string terminator") is either BEL (\x07) or ESC \ (\x1b\x5c). Both are accepted.
  • Keys and values are separated by =. Multiple fields are separated by ;.
  • Whitespace around keys/values is trimmed.
  • Unknown keys are silently ignored — safe to emit forward-compatibly.
  • The whole sequence is consumed by xterm and never rendered.

Recognised keys

Key Value format Effect
color #rgb, #rrggbb, #rrggbbaa Override the session accent. Repaints the sidebar stripe and the active-pane ring immediately. 8-digit values use alpha-last (#rrggbbaa) — CSM converts them internally to WPF's #aarrggbb format.
git-branch string Set the branch label shown in the sidebar. Bypasses CSM's local git polling — useful for SSH/remote sessions.
git-dirty 0/1 (or false/true) Toggle the dirty marker (*) shown next to the branch.
title string Rename the session (same as double-clicking the sidebar entry). Persisted to state.json.

Multiple keys can be sent in a single sequence; CSM applies them atomically and saves state once.

Examples

All examples below emit color=#a6e3a1, git-branch=feat/foo, git-dirty=1, title=my-repo in a single sequence. Adapt to your needs.

bash / zsh / sh

printf '\e]9001;color=#a6e3a1;git-branch=feat/foo;git-dirty=1;title=my-repo\e\\'

To refresh on every prompt, drop this into your shell init:

__csm_update() {
  local branch dirty
  branch=$(git symbolic-ref --short HEAD 2>/dev/null) || branch=""
  [ -n "$(git status --porcelain 2>/dev/null)" ] && dirty=1 || dirty=0
  printf '\e]9001;git-branch=%s;git-dirty=%s\e\\' "$branch" "$dirty"
}
PROMPT_COMMAND='__csm_update'    # bash
# precmd_functions+=(__csm_update)  # zsh

PowerShell

$esc = [char]27
"$esc]9001;color=#a6e3a1;git-branch=feat/foo;git-dirty=1;title=my-repo$esc\" | Write-Host -NoNewline

In a prompt function:

function prompt {
    $esc = [char]27
    $branch = (git symbolic-ref --short HEAD 2>$null)
    $dirty  = if ((git status --porcelain 2>$null)) { 1 } else { 0 }
    Write-Host -NoNewline "$esc]9001;git-branch=$branch;git-dirty=$dirty$esc\"
    "PS $($executionContext.SessionState.Path.CurrentLocation)> "
}

Python

import sys

def csm_update(**fields):
    payload = ";".join(f"{k}={v}" for k, v in fields.items())
    sys.stdout.write(f"\x1b]9001;{payload}\x1b\\")
    sys.stdout.flush()

csm_update(color="#a6e3a1", **{"git-branch": "feat/foo", "git-dirty": "1"}, title="my-repo")

Node.js

function csmUpdate(fields) {
  const payload = Object.entries(fields).map(([k, v]) => `${k}=${v}`).join(';');
  process.stdout.write(`\x1b]9001;${payload}\x1b\\`);
}

csmUpdate({ color: '#a6e3a1', 'git-branch': 'feat/foo', 'git-dirty': '1', title: 'my-repo' });

Rust

fn csm_update(fields: &[(&str, &str)]) {
    let payload: String = fields.iter()
        .map(|(k, v)| format!("{k}={v}"))
        .collect::<Vec<_>>()
        .join(";");
    print!("\x1b]9001;{payload}\x1b\\");
    use std::io::Write;
    let _ = std::io::stdout().flush();
}

csm_update(&[
    ("color", "#a6e3a1"),
    ("git-branch", "feat/foo"),
    ("git-dirty", "1"),
    ("title", "my-repo"),
]);

Go

package main

import (
    "fmt"
    "strings"
)

func csmUpdate(fields map[string]string) {
    parts := make([]string, 0, len(fields))
    for k, v := range fields {
        parts = append(parts, k+"="+v)
    }
    fmt.Printf("\x1b]9001;%s\x1b\\", strings.Join(parts, ";"))
}

Patterns

Update on every prompt. Cheap, predictable, and handles cd / branch switches automatically. Use the shell snippets above.

Update on relevant events only. If a prompt-hook is too coarse — e.g. inside a long-running TUI like nexus — call your update function whenever your internal state changes (new repo selected, dirty state changes, branch checked out, etc.).

Color is sticky. An emitted color= is stored on the session and persists across sleep/wake and app restarts. There is no wire-level "reset" — an empty or invalid value is ignored, not applied. If a different program later runs in the same session it inherits your color until it sets its own. The user can hand the color back to the default folder hash at any time with Reset accent color in the session's right-click menu.

Limitations

  • The protocol is one-way: CSM does not respond to OSC 9001 sequences with any data.
  • There's no acknowledgement that a sequence was parsed. Validate your output with the inspector if you want to be sure (DevTools is enabled in WebView2; press F12 inside a terminal pane).
  • Color values must be valid CSS hex (#rgb / #rrggbb / #rrggbbaa). Named colors and rgb() syntax are rejected.
  • Values cannot contain ; — it is the field separator and there is no escaping. A title=a;b is read as title=a plus an unknown key b. = inside a value is fine (only the first = splits key from value).
  • Titles are capped at 80 characters. Control characters are stripped, whitespace is trimmed, and a title that is empty after that is ignored (the existing name is kept). The same stripping applies to git-branch.
  • The terminating byte should be BEL or ESC \. xterm.js will eventually time out an unterminated OSC, but until then your text appears swallowed.

Pipeline (for CSM contributors)

terminal-init.js registers the OSC handler via term.parser.registerOscHandler(9001, …). The handler parses the payload, posts {type: "shellIntegration", fields: {…}} over the WebView2 message channel, and returns true so xterm consumes the sequence. TerminalBridge.OnWebMessageReceived raises ShellIntegrationReceived. MainWindow.LaunchSessionAsync subscribes and dispatches to SessionViewModel.ApplyShellIntegration(fields), then calls MainViewModel.SaveStateDebounced (one write per 500ms of quiet, so a chatty prompt hook can't hammer state.json). Validation and normalisation of the untrusted values — hex check, #rrggbbaa → #aarrggbb, title cap, control-character stripping — live in the WPF-free Services/ShellIntegrationPayload, which is what the unit tests target. Color/title changes propagate through INotifyPropertyChanged to repaint the sidebar stripe and active ring; git fields update GitBranch / GitIsDirty.