diff --git a/venus/app-configs/hammerspoon/screen_sharing_metrics.lua b/venus/app-configs/hammerspoon/screen_sharing_metrics.lua
index da0d208..c511743 100644
--- a/venus/app-configs/hammerspoon/screen_sharing_metrics.lua
+++ b/venus/app-configs/hammerspoon/screen_sharing_metrics.lua
@@ -1,5 +1,5 @@
--- Network probes for the connected Screen Sharing client and default router.
--- These are ICMP round trips, not measurements of the video stream itself.
+-- TCP RTT for the connected Screen Sharing client and ICMP probes for the router.
+-- Neither measures the video stream's end-to-end latency.
 local interval = 2
 local window = 60
 local staleAfter = 8
@@ -80,7 +80,9 @@ local function clientStatus(time)
   return "active"
 end
 
-local function metricText(label, target, status, time)
+local function routerText(status, time)
+  local label = "Rtr."
+  local target = router
   if status == "inactive" then return "No " .. label end
   if status ~= "active" then return label .. " " .. status end
   local stats = summary(target, time)
@@ -89,11 +91,18 @@ local function metricText(label, target, status, time)
   return string.format("%s %s/%.0f%%", label, latency, stats.loss)
 end
 
+local function clientText(time)
+  local status = clientStatus(time)
+  if status == "inactive" then return "No SS" end
+  if status ~= "active" then return "SS " .. status end
+  local stats = summary(client, time)
+  return stats.current and string.format("SS %.0fms", stats.current) or "SS —ms"
+end
+
 local function render()
   local time = now()
   local routerStatus = router.address and "active" or "inactive"
-  menu:setTitle(metricText("SS", client, clientStatus(time), time)
-    .. " | " .. metricText("Rtr.", router, routerStatus, time))
+  menu:setTitle(clientText(time) .. " | " .. routerText(routerStatus, time))
 end
 
 local function parseClient(output)
@@ -132,6 +141,49 @@ local function discoverClient()
   end
 end
 
+-- Read TCP's RTT estimate from the existing Screen Sharing socket; no client probe is sent.
+local function sampleClientRtt()
+  if not client.address or client.inFlight then return end
+  local address = client.address
+  client.inFlight = true
+  if not run("/usr/bin/nettop", { "-L", "1", "-m", "tcp", "-n", "-x", "-J", "rtt_avg" },
+    function(code, output)
+      client.inFlight = false
+      if client.address ~= address then return end
+      if code ~= 0 then
+        hs.printf("Could not read Screen Sharing TCP RTT from nettop")
+        render()
+        return
+      end
+      for line in (output or ""):gmatch("[^\r\n]+") do
+        local socket, rttText = line:match("^([^,]+),([^,]*),")
+        if socket then
+          local separator = socket:find("<->", 1, true)
+          if separator then
+            local localEndpoint = socket:sub(1, separator - 1)
+            local remoteEndpoint = socket:sub(separator + 3)
+            local remoteAddress = remoteEndpoint:match("^(.*)[:%.]%d+$")
+            if localEndpoint:match("[:%.]5900$") and remoteAddress == address then
+              local rtt = tonumber(rttText:match("^%s*([%d.]+)"))
+              if rtt then
+                local time = now()
+                local sample = { at = time, rtt = rtt }
+                table.insert(client.samples, sample)
+                client.lastSample = time
+                client.lastReply = sample
+                prune(client, time)
+                break
+              end
+            end
+          end
+        end
+      end
+      render()
+    end) then
+    client.inFlight = false
+  end
+end
+
 local function refreshRouter()
   local ok, data = pcall(function()
     return store:contents("State:/Network/Global/IPv4")
@@ -140,6 +192,21 @@ local function refreshRouter()
   setAddress(router, state and state.Router or nil)
 end
 
+local function clientDetail(time)
+  local status = clientStatus(time)
+  if status ~= "active" then
+    return { title = "SS TCP RTT: " .. status, disabled = true }
+  end
+  local stats = summary(client, time)
+  return {
+    { title = "SS TCP RTT (avg): " .. client.address, disabled = true },
+    { title = "Latest sample: " .. (stats.current and string.format("%.1f ms", stats.current)
+      or (stats.stale and "stale" or "unavailable")), disabled = true, indent = 1 },
+    { title = "60s peak sample: " .. (stats.peak and string.format("%.1f ms", stats.peak) or "—"),
+      disabled = true, indent = 1 },
+  }
+end
+
 local function probe(target)
   if not target.address or target.inFlight then return end
   local address = target.address
@@ -194,7 +261,7 @@ menu:setMenu(function()
     if rows.title then rows = { rows } end
     for _, row in ipairs(rows) do table.insert(items, row) end
   end
-  append(detail("Screen Sharing client", client, clientStatus(time), time))
+  append(clientDetail(time))
   table.insert(items, { title = "-" })
   append(detail("Router", router, router.address and "active" or "inactive", time))
   table.insert(items, { title = "-" })
@@ -202,14 +269,14 @@ menu:setMenu(function()
   local signal = ok and wifi and wifi.rssi
   table.insert(items, { title = "Wi-Fi signal: " ..
     (signal and string.format("%d dBm", signal) or "unavailable"), disabled = true })
-  table.insert(items, { title = "ICMP round trips; not video latency", disabled = true })
+  table.insert(items, { title = "SS: TCP RTT; router: ICMP. Not video latency", disabled = true })
   return items
 end)
 
 local function tick()
   refreshRouter()
   discoverClient()
-  if clientStatus(now()) == "active" then probe(client) end
+  if clientStatus(now()) == "active" then sampleClientRtt() end
   probe(router)
   render()
 end