diff --git a/README.md b/README.md
index 75a48ed..989a156 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,7 @@ test: go::test go::docs-check bats::test
 | `unit` | Run unit tests |
 | `unit-int` | Run integration tests (requires running service) |
 | `unit-cov` | Run tests with coverage |
+| `unit-cov-gaps` | Coverage gaps only with HTML heatmap |
 | `unit-cov-map` | Coverage with HTML heatmap |
 | `test` | Run all checks (mod, fmt, vet, coverage) |
 | `fmt` | Auto-format with gofumpt + golines |
diff --git a/go.just b/go.just
index 547722a..d7761c1 100644
--- a/go.just
+++ b/go.just
@@ -101,6 +101,16 @@ unit-cov: _cov-deps
     go tool github.com/boumenot/gocover-cobertura < {{ coverage_dir }}/cover.out > {{ coverage_dir }}/cobertura.xml
     go tool cover -func={{ coverage_dir }}/cover.out
 
+# Show files without 100% coverage and open heatmap of only those files
+[group('test')]
+unit-cov-gaps: unit-cov
+    #!/usr/bin/env bash
+    set -euo pipefail
+    gap_files=$(go tool cover -func={{ coverage_dir }}/cover.out | grep -v '100.0%' | grep -v '^total:' | awk -F: '{print $1}' | sort -u)
+    if [ -z "$gap_files" ]; then echo "No coverage gaps found."; exit 0; fi
+    { head -1 {{ coverage_dir }}/cover.out; grep -F -f <(echo "$gap_files") {{ coverage_dir }}/cover.out; } > {{ coverage_dir }}/gaps.out
+    go tool cover -html={{ coverage_dir }}/gaps.out
+
 # Generate coverage and show heatmap
 [group('test')]
 unit-cov-map: unit-cov