diff --git a/cmd/dndcheck/main.go b/cmd/dndcheck/main.go
new file mode 100644
index 0000000..b6864dd
--- /dev/null
+++ b/cmd/dndcheck/main.go
@@ -0,0 +1,88 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"github.com/samber/lo"
+)
+
+var mapSigs = map[string]string{
+	"./*.jpg;./*.psd;Objects/*.png": "patreon-drmapzo-diamond",
+}
+
+func main() {
+	root := flag.String("root", "", "root directory to validate")
+
+	flag.Parse()
+
+	if *root == "" {
+		log.Fatal("please specify --root")
+	}
+
+	log.Printf("validating: %s", *root)
+
+	rootFS := os.DirFS(*root)
+
+	validateMaps(lo.Must(fs.Sub(rootFS, "Maps")))
+}
+
+func validateMaps(mapsFS fs.FS) {
+	entries := lo.Must(mapsFS.(fs.ReadDirFS).ReadDir("."))
+
+	for _, entry := range entries {
+		if strings.HasPrefix(entry.Name(), ".") {
+			continue
+		}
+
+		log.Printf("map: %s", entry.Name())
+
+		mapFS := lo.Must(fs.Sub(mapsFS, entry.Name()))
+		validateMap(mapFS)
+	}
+}
+
+func validateMap(mapFS fs.FS) {
+	sig := getDirSig(mapFS)
+
+	t := mapSigs[sig]
+	if t == "" {
+		log.Fatalf("\tunrecognized signature: %s", sig)
+	}
+
+	log.Printf("\ttype: %s", t)
+}
+
+func getDirSig(root fs.FS) string {
+	sigSet := map[string]bool{}
+
+	fs.WalkDir(root, ".", func(path string, entry fs.DirEntry, err error) error {
+		if entry.IsDir() {
+			return nil
+		}
+
+		if strings.HasPrefix(entry.Name(), ".") {
+			return nil
+		}
+
+		sigSet[getPathSig(path)] = true
+
+		return nil
+	})
+
+	sigs := lo.Keys(sigSet)
+	sort.Strings(sigs)
+
+	return strings.Join(sigs, ";")
+}
+
+func getPathSig(path string) string {
+	parts := strings.Split(filepath.Base(path), ".")
+	return fmt.Sprintf("%s/*.%s", filepath.Dir(path), lo.Must(lo.Last(parts)))
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..05606f7
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,7 @@
+module github.com/firestuff/dnd
+
+go 1.20
+
+require github.com/samber/lo v1.38.1
+
+require golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17 // indirect
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..7a26b7e
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,4 @@
+github.com/samber/lo v1.38.1 h1:j2XEAqXKb09Am4ebOg31SpvzUTTs6EN3VfgeLUhPdXM=
+github.com/samber/lo v1.38.1/go.mod h1:+m/ZKRl6ClXCE2Lgf3MsQlWfh4bn1bz6CXEOxnEXnEA=
+golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17 h1:3MTrJm4PyNL9NBqvYDSj3DHl46qQakyfqfWo4jgfaEM=
+golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17/go.mod h1:lgLbSvA5ygNOMpwM/9anMpWVlVJ7Z+cHWq/eFuinpGE=