diff --git a/src/matrix_harness.zig b/src/matrix_harness.zig
index f89b36a..a468538 100644
--- a/src/matrix_harness.zig
+++ b/src/matrix_harness.zig
@@ -561,13 +561,19 @@ pub fn main(init: std.process.Init) !void {
             if (!std.mem.eql(u8, ev.sender, peer)) continue;
             if (ev.body.len == 0) continue;
 
-            var ts_buf: [16]u8 = undefined;
+            var ts_buf: [24]u8 = undefined;
             const ts_str: []const u8 = blk: {
                 if (ev.ts <= 0) break :blk "";
                 const secs: u64 = @intCast(@divTrunc(ev.ts, 1000));
                 const epoch = std.time.epoch.EpochSeconds{ .secs = secs };
+                const day = epoch.getEpochDay();
+                const year_day = day.calculateYearDay();
+                const month_day = year_day.calculateMonthDay();
                 const sod = epoch.getDaySeconds();
-                break :blk std.fmt.bufPrint(&ts_buf, " {d:0>2}:{d:0>2}Z", .{ sod.getHoursIntoDay(), sod.getMinutesIntoHour() }) catch "";
+                break :blk std.fmt.bufPrint(&ts_buf, " {d:0>4}-{d:0>2}-{d:0>2} {d:0>2}:{d:0>2}Z", .{
+                    year_day.year, month_day.month.numeric(), month_day.day_index + 1,
+                    sod.getHoursIntoDay(), sod.getMinutesIntoHour(),
+                }) catch "";
             };
 
             // Attachment: download locally and forward the path to the agent.