diff --git a/.github/workflows/ci-swift.yml b/.github/workflows/ci-swift.yml
index 01d1598..33ec293 100644
--- a/.github/workflows/ci-swift.yml
+++ b/.github/workflows/ci-swift.yml
@@ -73,26 +73,29 @@ jobs:
 
       - name: Coverage smoke test (math_test)
         run: |
-          ./pleasew --plain_output cover //test/swift/lib:math_test  2>&1 | tee cover.log
-          grep -Eq '^\s+Math\.swift [1-9][0-9]*/' cover.log
+          ./pleasew --plain_output build //tools/common/lcovcheck
+          ./pleasew --plain_output cover //test/swift/lib:math_test
+          plz-out/bin/tools/common/lcovcheck/lcovcheck -coverage-json plz-out/log/coverage.json -covered test/swift/lib/Math.swift
         env:
           VERITAS_NO_HOOK: "1"
 
       - name: Coverage smoke test (mid_test, transitive dependencies)
         run: |
-          ./pleasew --plain_output cover //test/swift/chain:mid_test  2>&1 | tee cover.log
-          grep -Eq '^\s+Mid\.swift [1-9][0-9]*/' cover.log
-          grep -Eq '^\s+Base\.swift [1-9][0-9]*/' cover.log
+          ./pleasew --plain_output build //tools/common/lcovcheck
+          ./pleasew --plain_output cover //test/swift/chain:mid_test
+          plz-out/bin/tools/common/lcovcheck/lcovcheck -coverage-json plz-out/log/coverage.json \
+            -covered test/swift/chain/Mid.swift -covered test/swift/chain/Base.swift
         env:
           VERITAS_NO_HOOK: "1"
 
       - name: Raw lcov export smoke test (functions and branches)
         run: |
-          ./pleasew --plain_output cover --rerun //test/swift/branches:branches_test 2>&1 | tee cover.log
-          f="plz-out/bin/test/swift/branches/branches_test.lcov"
-          grep -q '^SF:test/swift/branches/Branches\.swift$' "$f"
-          grep -Eq '^FNDA:0,.*unused' "$f"
-          grep -q '^BRDA:4,0,1,0$' "$f"
-          grep -q '^BRDA:12,0,0,0$' "$f"
+          ./pleasew --plain_output build //tools/common/lcovcheck
+          ./pleasew --plain_output cover --rerun //test/swift/branches:branches_test
+          plz-out/bin/tools/common/lcovcheck/lcovcheck \
+            -lcov plz-out/bin/test/swift/branches/branches_test.lcov \
+            -path test/swift/branches/Branches.swift \
+            -line 4=partial -line 12=partial -line 5=uncovered \
+            -function unused=missed -function classify=2
         env:
           VERITAS_NO_HOOK: "1"