diff --git a/src/terminal/Terminal.zig b/src/terminal/Terminal.zig
index ac11ead3e..727b71b58 100644
--- a/src/terminal/Terminal.zig
+++ b/src/terminal/Terminal.zig
@@ -17,6 +17,7 @@ const charsets = @import("charsets.zig");
 const csi = @import("csi.zig");
 const hyperlink = @import("hyperlink.zig");
 const kitty = @import("kitty.zig");
+const osc = @import("osc.zig");
 const point = @import("point.zig");
 const sgr = @import("sgr.zig");
 const Tabstops = @import("Tabstops.zig");
@@ -1058,6 +1059,65 @@ pub fn setProtectedMode(self: *Terminal, mode: ansi.ProtectedMode) void {
     }
 }
 
+/// Perform a semantic prompt command.
+///
+/// If there is an error, we do our best to get the terminal into
+/// some coherent state, since callers typically can't handle errors
+/// (since they're sending sequences via the pty).
+pub fn semanticPrompt(
+    self: *Terminal,
+    cmd: osc.Command.SemanticPrompt,
+) !void {
+    switch (cmd.action) {
+        .fresh_line => try self.semanticPromptFreshLine(),
+        .fresh_line_new_prompt => {
+            // "First do a fresh-line."
+            try self.semanticPromptFreshLine();
+
+            // "Subsequent text (until a OSC "133;B" or OSC "133;I" command)
+            // is a prompt string (as if followed by OSC 133;P;k=i\007)."
+            // TODO
+
+            // The "aid" and "cl" options are also valid for this
+            // command but we don't yet handle these in any meaningful way.
+        },
+
+        else => {},
+    }
+}
+
+fn semanticPromptSet(
+    self: *Terminal,
+    mode: pagepkg.Cell.SemanticContent,
+) void {
+    // We always reset this when we mode change. The caller can set it
+    // again after if they care.
+    self.screens.active.cursor.semantic_content_clear_eol = false;
+
+    // Update our mode
+    self.screens.active.cursor.semantic_content = mode;
+}
+
+// OSC 133;L
+fn semanticPromptFreshLine(self: *Terminal) !void {
+    const left_margin = if (self.screens.active.cursor.x < self.scrolling_region.left)
+        0
+    else
+        self.scrolling_region.left;
+
+    // Spec: "If the cursor is the initial column (left, assuming
+    // left-to-right writing), do nothing" This specification is very under
+    // specified. We are taking the liberty to assume that in a left/right
+    // margin context, if the cursor is outside of the left margin, we treat
+    // it as being at the left margin for the purposes of this command.
+    // This is arbitrary. If someone has a better reasonable idea we can
+    // apply it.
+    if (self.screens.active.cursor.x == left_margin) return;
+
+    self.carriageReturn();
+    try self.index();
+}
+
 /// The semantic prompt type. This is used when tracking a line type and
 /// requires integration with the shell. By default, we mark a line as "none"
 /// meaning we don't know what type it is.
diff --git a/src/terminal/stream_readonly.zig b/src/terminal/stream_readonly.zig
index 18ed0dd42..75e7cf129 100644
--- a/src/terminal/stream_readonly.zig
+++ b/src/terminal/stream_readonly.zig
@@ -153,7 +153,7 @@ pub const Handler = struct {
             .full_reset => self.terminal.fullReset(),
             .start_hyperlink => try self.terminal.screens.active.startHyperlink(value.uri, value.id),
             .end_hyperlink => self.terminal.screens.active.endHyperlink(),
-            .semantic_prompt => self.semanticPrompt(value),
+            .semantic_prompt => try self.semanticPrompt(value),
             .mouse_shape => self.terminal.mouse_shape = value,
             .color_operation => try self.colorOperation(value.op, &value.requests),
             .kitty_color_report => try self.kittyColorOperation(value),
@@ -212,7 +212,9 @@ pub const Handler = struct {
     fn semanticPrompt(
         self: *Handler,
         cmd: Action.SemanticPrompt,
-    ) void {
+    ) !void {
+        try self.terminal.semanticPrompt(cmd);
+
         switch (cmd.action) {
             .fresh_line_new_prompt => {
                 const kind = cmd.readOption(.prompt_kind) orelse .initial;
@@ -905,3 +907,16 @@ test "palette dirty flag set on color change" {
     try s.nextSlice("\x1b]21;1=rgb:00/ff/00\x1b\\");
     try testing.expect(t.flags.dirty.palette);
 }
+
+test "semantic prompt fresh line" {
+    var t: Terminal = try .init(testing.allocator, .{ .cols = 10, .rows = 10 });
+    defer t.deinit(testing.allocator);
+
+    var s: Stream = .initAlloc(testing.allocator, .init(&t));
+    defer s.deinit();
+
+    try s.nextSlice("Hello");
+    try s.nextSlice("\x1b]133;L\x07");
+    try testing.expectEqual(@as(usize, 0), t.screens.active.cursor.x);
+    try testing.expectEqual(@as(usize, 1), t.screens.active.cursor.y);
+}