diff --git a/check.sh b/check.sh
index a9cdc83..e8d39c1 100755
--- a/check.sh
+++ b/check.sh
@@ -16,29 +16,72 @@ HEAD="${HEAD_SHA:-}"
 VISIBLE_BODY=$(printf '%s\n' "${BODY}" | awk '
   {
     line=$0
-    while (line != "") {
+    fence_pos=1
+    while (fence_pos <= 4 && substr(line, fence_pos, 1) == " ") fence_pos++
+    fence_char=substr(line, fence_pos, 1)
+    fence_run=0
+    if (fence_char == "`" || fence_char == "~") {
+      while (substr(line, fence_pos + fence_run, 1) == fence_char) fence_run++
+    }
+    if (in_fence) {
+      print line
+      if (fence_char == active_fence_char && fence_run >= active_fence_run) in_fence=0
+      next
+    }
+    if (fence_run >= 3) {
+      in_fence=1
+      active_fence_char=fence_char
+      active_fence_run=fence_run
+      print line
+      next
+    }
+
+    visible=""
+    pos=1
+    while (pos <= length(line)) {
       if (in_comment) {
-        end=index(line, "-->")
-        if (end == 0) {
-          line=""
+        rest=substr(line, pos)
+        comment_end=index(rest, "-->")
+        if (comment_end == 0) {
+          pos=length(line) + 1
           break
         }
-        line=substr(line, end + 3)
+        visible=visible " "
+        pos += comment_end + 2
         in_comment=0
+        continue
       }
-      start=index(line, "<!--")
-      if (start == 0) break
-      before=substr(line, 1, start - 1)
-      rest=substr(line, start + 4)
-      end=index(rest, "-->")
-      if (end == 0) {
-        line=before
+
+      if (substr(line, pos, 1) == "`") {
+        ticks=1
+        while (substr(line, pos + ticks, 1) == "`") ticks++
+        close_pos=pos + ticks
+        found_close=0
+        while (close_pos <= length(line)) {
+          if (substr(line, close_pos, ticks) == substr(line, pos, ticks) &&
+              substr(line, close_pos + ticks, 1) != "`") {
+            found_close=1
+            break
+          }
+          close_pos++
+        }
+        if (found_close) {
+          visible=visible substr(line, pos, close_pos + ticks - pos)
+          pos=close_pos + ticks
+          continue
+        }
+      }
+
+      if (substr(line, pos, 4) == "<!--") {
+        visible=visible " "
         in_comment=1
-        break
+        pos += 4
+        continue
       }
-      line=before substr(rest, end + 3)
+      visible=visible substr(line, pos, 1)
+      pos++
     }
-    print line
+    print visible
   }
 ')
 
diff --git a/tests/run b/tests/run
index 8031790..bfb7df1 100755
--- a/tests/run
+++ b/tests/run
@@ -57,6 +57,22 @@ check_contract() {
   fi
 }
 
+check_contract_pass() {
+  local desc="$1" body="$2" base="$3" head="$4"
+  local out rc=0
+  out=$(cd "${FIXTURES}" && HEAD_BRANCH="architect/bug-x7k2m9/contract" \
+    PR_TITLE="[bug-x7k2m9] Enforce contract" PR_AUTHOR="architect" \
+    PR_BODY="$body" BASE_SHA="$base" HEAD_SHA="$head" bash "$SCRIPT" 2>&1) || rc=$?
+  if [ "$rc" -eq 0 ] && printf '%s\n' "$out" | grep -Fq "check-naming: ok"; then
+    echo "PASS [$desc]"
+    PASS=$((PASS + 1))
+  else
+    echo "FAIL [$desc]: expected exit=0 and check-naming: ok, got exit=$rc"
+    echo "  output: $out"
+    FAIL=$((FAIL + 1))
+  fi
+}
+
 # break-glass
 check "dfritz exempt — invalid branch"  0 "totally/wrong-branch" "no prefix"               "dfritz"
 check "dfritz exempt — mismatch"        0 "dev/bug-abc/thing"    "[bug-xyz] Thing"          "dfritz"
@@ -107,6 +123,15 @@ check_contract "attribution must be in its own section" \
 check_contract "hidden provenance does not satisfy the visible contract" \
   $'<!--\n## Tracking\n- Fixes bug-x7k2m9 — https://agenthub.fritzlab.net/bug-x7k2m9\n\n## Attribution\n- Authored-By: Codex (GPT-5) <noreply@openai.com>\n-->' \
   "$BASE" "$GOOD_HEAD" "PR body must contain a non-empty ## Tracking section"
+check_contract "comment removal cannot synthesize section headings" \
+  $'<!-- hidden -->## Tracking\n- Fixes bug-x7k2m9 — https://agenthub.fritzlab.net/bug-x7k2m9\n\n<!-- hidden -->## Attribution\n- Authored-By: Codex (GPT-5) <noreply@openai.com>' \
+  "$BASE" "$GOOD_HEAD" "PR body must contain a non-empty ## Tracking section"
+check_contract_pass "inline code containing comment opener stays visible" \
+  $'Use `<!--` when documenting an HTML comment opener.\n\n## Tracking\n- Fixes bug-x7k2m9 — https://agenthub.fritzlab.net/bug-x7k2m9\n\n## Attribution\n- Authored-By: Codex (GPT-5) <noreply@openai.com>' \
+  "$BASE" "$GOOD_HEAD"
+check_contract_pass "fenced code containing comments stays visible" \
+  $'```html\n<!-- example -->\n```\n\n## Tracking\n- Fixes bug-x7k2m9 — https://agenthub.fritzlab.net/bug-x7k2m9\n\n## Attribution\n- Authored-By: Codex (GPT-5) <noreply@openai.com>' \
+  "$BASE" "$GOOD_HEAD"
 
 git -C "${FIXTURES}" commit --allow-empty -q -m "unwatermarked change"
 BAD_HEAD=$(git -C "${FIXTURES}" rev-parse HEAD)