diff --git a/scripts/ci/desktop-linux/claude-test.md b/scripts/ci/desktop-linux/claude-test.md
index 2bc77de2a1..aeba41766b 100644
--- a/scripts/ci/desktop-linux/claude-test.md
+++ b/scripts/ci/desktop-linux/claude-test.md
@@ -22,7 +22,7 @@ Run all of A and B in the default layout, with the toolbar at the bottom. Then m
 4. Use "Show more" until both #ci_group and #ci_channel are listed, and note how many pages that took.
 5. Check, noting the evidence (screenshot names, positions):
    - each result's row shows its name, its description, its count ("2 members" or "1 subscriber") and "Join group" (#ci_group) or "Join channel" (#ci_channel);
-   - the count's text is smaller than the description's above it;
+   - the count's text is smaller than the description's above it: compare `ui ink "1 subscriber"` with `ui ink "CI seeded channel"`, and look at the screenshot;
    - each shows its avatar, filling the picture: run `ui avatar "#ci_group" red` and `ui avatar "#ci_channel" green`, and look at the screenshot;
    - **(both layouts)** the "Directory" header is above its results;
    - **(both layouts)** no "Show more" is left, and nothing is cut off, overlapping or garbled.
diff --git a/scripts/ci/desktop-linux/screen-ink.py b/scripts/ci/desktop-linux/screen-ink.py
new file mode 100755
index 0000000000..427f4c6875
--- /dev/null
+++ b/scripts/ci/desktop-linux/screen-ink.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+
+# Prints the height in pixels of the ink in a box of a screenshot: from the first to the last row with a pixel darker than
+# halfway between the box's lightest and darkest. OCR's boxes are padded, so they hardly tell text sizes apart.
+#
+#   screen-ink.py <gray.pgm> <left> <top> <right> <bottom>
+#
+# <gray.pgm> is the screenshot in 8-bit grayscale; the box is in its pixels, edges included.
+
+import re
+import sys
+
+
+def main():
+    path, left, top, right, bottom = sys.argv[1], *map(int, sys.argv[2:6])
+    with open(path, "rb") as f:
+        data = f.read()
+    header = re.match(rb"P5\s+(\d+)\s+(\d+)\s+(\d+)\s", data)
+    width, height, pixels = int(header[1]), int(header[2]), data[header.end():]
+    columns = range(max(left, 0), min(right, width - 1) + 1)
+    rows = [[pixels[y * width + x] for x in columns] for y in range(max(top, 0), min(bottom, height - 1) + 1)]
+    threshold = (max(map(max, rows)) + min(map(min, rows))) / 2
+    ink = [i for i, row in enumerate(rows) if min(row) < threshold]
+    print(ink[-1] - ink[0] + 1 if ink else 0)
+
+
+main()
diff --git a/scripts/ci/desktop-linux/smoke-test.sh b/scripts/ci/desktop-linux/smoke-test.sh
index 1486aee818..09b7364af6 100755
--- a/scripts/ci/desktop-linux/smoke-test.sh
+++ b/scripts/ci/desktop-linux/smoke-test.sh
@@ -121,12 +121,6 @@ y_of() {
   cut -d ' ' -f 2 <<< "$pos"
 }
 
-height_of() {
-  local x y l t r b
-  read -r x y l t r b < <("$ui" find "$1") || return 1
-  echo $((b - t))
-}
-
 above() {
   local a b
   a=$(y_of "$1") || return 1
@@ -175,9 +169,9 @@ scroll_to() {
 # the count's text is smaller than the description's above it: both have capitals and ascenders, no descenders
 count_text_smaller() {
   local count description
-  count=$(height_of "1 subscriber") || return 1
-  description=$(height_of "CI seeded channel") || return 1
-  echo "NOTE text heights: \"1 subscriber\" $count px, \"CI seeded channel\" $description px" | tee -a "$checks"
+  count=$("$ui" ink "1 subscriber") || return 1
+  description=$("$ui" ink "CI seeded channel") || return 1
+  echo "NOTE ink heights: \"1 subscriber\" $count px, \"CI seeded channel\" $description px" | tee -a "$checks"
   [ "$count" -lt "$description" ]
 }
 
diff --git a/scripts/ci/desktop-linux/ui b/scripts/ci/desktop-linux/ui
index a96515f988..83c6f74bc0 100755
--- a/scripts/ci/desktop-linux/ui
+++ b/scripts/ci/desktop-linux/ui
@@ -11,6 +11,7 @@
 #   ui shot <name>                save UI_OUT/NN-<name>.png and NN-<name>.txt (OCR's input and output in UI_OUT/ocr), and print the text on screen
 #   ui text                       print the text on screen, one phrase per line after its centre x,y
 #   ui find <text>                print "x y left top right bottom", the text's centre and box; fail if it is not on screen
+#   ui ink <text>                 print the height in pixels of the text's ink, to compare text sizes
 #   ui wait <text> [secs]         wait up to secs (30) until the text is on screen
 #   ui click <x> <y>              click at x,y
 #   ui click-text <text> [secs]   wait up to secs (20) for the text and click its centre
@@ -209,6 +210,17 @@ case "${1:-}" in
     log "find \"$2\": $pos" > /dev/null
     echo "$pos"
     ;;
+  ink)
+    if ! pos=$(screen_ocr find "$2"); then
+      log "ink \"$2\": not on screen" >&2
+      exit 1
+    fi
+    read -r _ _ l t r b <<< "$pos"
+    # 2 px around OCR's box, less than the gap between lines
+    h=$(python3 "$here/screen-ink.py" "$state/ocr/gray.pgm" "$l" $((t - 2)) "$r" $((b + 2)))
+    log "ink \"$2\": $h px" > /dev/null
+    echo "$h"
+    ;;
   wait)
     secs=${3:-30}
     if ! pos=$(wait_for "$2" "$secs"); then