diff --git a/pkgs/default.nix b/pkgs/default.nix
index c9e755a..03f9cc3 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -26,6 +26,8 @@ pkgs.lib.makeScope pkgs.newScope (pkgs: {
 
   osc52 = pkgs.callPackage ./osc52 { };
 
+  osc777 = pkgs.callPackage ./osc777 { };
+
   rbw-pass = pkgs.callPackage ./rbw-pass { };
 
   unbound-zones-adblock = pkgs.callPackage ./unbound-zones-adblock { };
diff --git a/pkgs/osc777/default.nix b/pkgs/osc777/default.nix
new file mode 100644
index 0000000..6e9ce2e
--- /dev/null
+++ b/pkgs/osc777/default.nix
@@ -0,0 +1,41 @@
+{ lib, coreutils, makeWrapper, stdenvNoCC }:
+stdenvNoCC.mkDerivation rec {
+  pname = "osc777";
+  version = "0.1.0";
+
+  src = ./osc777;
+
+  nativeBuildInputs = [
+    makeWrapper
+  ];
+
+  dontUnpack = true;
+
+  dontBuild = true;
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp $src $out/bin/osc777
+    chmod a+x $out/bin/osc777
+  '';
+
+  wrapperPath = lib.makeBinPath [
+    coreutils
+  ];
+
+  fixupPhase = ''
+    patchShebangs $out/bin/osc777
+    wrapProgram $out/bin/osc777 --prefix PATH : "${wrapperPath}"
+  '';
+
+  meta = with lib; {
+    description = ''
+      A script to send notifications using the OSC777 escape sequence
+    '';
+    homepage = "https://git.belanyi.fr/ambroisie/nix-config";
+    license = with licenses; [ mit ];
+    mainProgram = "osc777";
+    maintainers = with maintainers; [ ambroisie ];
+    platforms = platforms.linux;
+  };
+}
diff --git a/pkgs/osc777/osc777 b/pkgs/osc777/osc777
new file mode 100755
index 0000000..83d066f
--- /dev/null
+++ b/pkgs/osc777/osc777
@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+
+# Whether to disable tmux/screen DCS escape sequences
+: "${OSC777_NO_DCS:=0}"
+
+die() {
+    echo "ERROR: $*"
+    exit 1
+}
+
+usage() {
+    if [ $# -gt 0 ]; then
+        exec 1>&2
+    fi
+
+    cat << EOF
+Usage: $0 [options] <title> <message>
+Send a notification (title and message) to the host system using the OSC 777
+escape sequence:
+Options:
+  -h, --help    This screen.
+  -d, --no-dcs  Disable tmux/screen specific DCS sequences, only use OSC 777
+  --            Stop options processing
+EOF
+
+    if [ $# -gt 0 ]; then
+        echo
+        die "$@"
+    else
+        exit 0
+    fi
+}
+
+tmux_seq() {
+    # shellcheck disable=1003
+    printf '\033Ptmux;\033%s\033\\' "$1"
+}
+
+screen_seq() {
+    # Screen limits the length of string sequences, so we have to break it up.
+    # Going by the screen history:
+    #   (v4.2.1) Apr 2014 - today: 768 bytes
+    #   Aug 2008 - Apr 2014 (v4.2.0): 512 bytes
+    #   ??? - Aug 2008 (v4.0.3): 256 bytes
+    local limit=768
+    # We go 4 bytes under the limit because we're going to insert two bytes
+    # before (\eP) and 2 bytes after (\e\) each string.
+    printf '%s' "$1" |
+        sed -E "s:.{$((limit - 4))}:&\n:g" |
+        sed -E -e 's:^:\x1bP:' -e 's:$:\x1b\\:' |
+        tr -d '\n'
+}
+
+osc777_seq() {
+    printf '%s' "$1"
+}
+
+print_seq() {
+    local seq="$1"
+
+    if [ "${OSC777_NO_DCS}" != 0 ]; then
+        # Override TERM to avoid tmux/screen DCS escape logic
+        TERM=dummy
+    fi
+
+    case ${TERM-} in
+        screen*)
+            # Since tmux defaults to setting TERM=screen, special case it.
+            if [ -n "${TMUX-}" ]; then
+                tmux_seq "${seq}"
+            else
+                screen_seq "${seq}"
+            fi
+            ;;
+        tmux*)
+            tmux_seq "${seq}"
+            ;;
+        *)
+            osc777_seq "${seq}"
+            ;;
+    esac
+}
+
+notify() {
+    local title=$1
+    local message=$2
+
+    # shellcheck disable=1003
+    print_seq "$(printf '\033]777;notify;%s;%s\e\\' "${title}" "${message}")"
+}
+
+main() {
+    set -e
+
+    local args=()
+    while [ $# -gt 0 ]; do
+        case $1 in
+            -h | --help)
+                usage
+                ;;
+            -d | --no-dcs)
+                OSC777_NO_DCS=1
+                ;;
+            --)
+                shift
+                args+=("$@")
+                break
+                ;;
+            -*)
+                usage "Unknown option: $1"
+                ;;
+            *)
+                args+=("$1")
+                ;;
+        esac
+        shift
+    done
+
+    if [ "${#args[@]}" -ne 2 ]; then
+        usage "Supply exactly two arguments"
+    fi
+
+    notify "${args[@]}"
+}
+
+main "$@"