diff --git a/justfile b/justfile
index f7494d8..27c800e 100644
--- a/justfile
+++ b/justfile
@@ -22,7 +22,7 @@ run:
 
 # Run all tests with coverage
 test:
-    cargo llvm-cov --features test-helpers --ignore-filename-regex "ports/fakes"
+    ./scripts/check_coverage.sh
 
 # Lint (zero warnings enforced)
 lint:
diff --git a/scripts/check_coverage.sh b/scripts/check_coverage.sh
new file mode 100755
index 0000000..70e5fe6
--- /dev/null
+++ b/scripts/check_coverage.sh
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+export PATH="$HOME/.cargo/bin:$PATH"
+
+echo "Running cargo-llvm-cov (generating JSON report)..."
+# Generate JSON + text report; do not fail immediately so we can print friendly summary
+cargo llvm-cov --features test-helpers --ignore-filename-regex "ports/fakes" --json --output-path cov.json || true
+
+if [ ! -f cov.json ]; then
+  echo "ERROR: cov.json not found. cargo-llvm-cov failed to produce JSON output."
+  exit 1
+fi
+
+# Extract totals
+lines_count=$(jq -r '.data[0].totals.lines.count' cov.json)
+lines_covered=$(jq -r '.data[0].totals.lines.covered' cov.json)
+lines_percent=$(jq -r '.data[0].totals.lines.percent' cov.json)
+functions_percent=$(jq -r '.data[0].totals.functions.percent' cov.json)
+regions_percent=$(jq -r '.data[0].totals.regions.percent' cov.json)
+
+# Normalize null to 0
+lines_percent=${lines_percent:-0}
+functions_percent=${functions_percent:-0}
+regions_percent=${regions_percent:-0}
+
+printf "\nCoverage summary:\n"
+printf "  Lines:     %s%%  (%s/%s)\n" "$lines_percent" "$lines_covered" "$lines_count"
+printf "  Functions: %s%%\n" "$functions_percent"
+printf "  Regions:   %s%%\n" "$regions_percent"
+
+# Enforce threshold
+threshold=90
+# Use awk for numeric comparison (handles floats)
+cmp=$(awk -v p="$lines_percent" -v t="$threshold" 'BEGIN{ if (p+0 >= t+0) print 0; else print 1 }')
+if [ "$cmp" -eq 0 ]; then
+  echo "Coverage check: PASS (>= ${threshold}%)"
+  exit 0
+else
+  echo "Coverage check: FAIL (< ${threshold}%)"
+  exit 1
+fi