diff --git a/tools/compliance/readgraph.go b/tools/compliance/readgraph.go
index 6f91e1c..7516440 100644
--- a/tools/compliance/readgraph.go
+++ b/tools/compliance/readgraph.go
@@ -18,6 +18,7 @@
 	"fmt"
 	"io"
 	"io/fs"
+	"os"
 	"strings"
 	"sync"
 
@@ -31,6 +32,22 @@
 	ConcurrentReaders = 5
 )
 
+type globalFS struct{}
+
+func (s globalFS) Open(name string) (fs.File, error) {
+	return os.Open(name)
+}
+
+var FS globalFS
+
+// GetFS returns a filesystem for accessing files under the OUT_DIR environment variable.
+func GetFS(outDir string) fs.FS {
+	if len(outDir) > 0 {
+		return os.DirFS(outDir)
+	}
+	return os.DirFS(".")
+}
+
 // result describes the outcome of reading and parsing a single license metadata file.
 type result struct {
 	// file identifies the path to the license metadata file