diff --git a/internal/lore/catalog.go b/internal/lore/catalog.go
index ddfb13c..b1b7dfb 100644
--- a/internal/lore/catalog.go
+++ b/internal/lore/catalog.go
@@ -62,6 +62,24 @@ func Catalog(ctx context.Context, db *sql.DB, p *CatalogParams) (*CatalogResult,
 	if strings.TrimSpace(p.Dir) == "" {
 		return nil, fmt.Errorf("lore: catalog: dir required")
 	}
+	if p.Kind != "" {
+		valid := false
+		for _, k := range AllKinds() {
+			if p.Kind == k {
+				valid = true
+				break
+			}
+		}
+		if !valid {
+			return nil, fmt.Errorf("lore: catalog: invalid kind %q: valid kinds are %s", p.Kind, strings.Join(func() []string {
+				kinds := make([]string, len(AllKinds()))
+				for i, k := range AllKinds() {
+					kinds[i] = string(k)
+				}
+				return kinds
+			}(), ", "))
+		}
+	}
 
 	info, err := os.Stat(p.Dir)
 	if err != nil {
diff --git a/internal/lore/catalog_cmd.go b/internal/lore/catalog_cmd.go
index bb72f3b..9dbe38c 100644
--- a/internal/lore/catalog_cmd.go
+++ b/internal/lore/catalog_cmd.go
@@ -38,6 +38,24 @@ var CatalogCommand = &command.Command[CatalogInput, CatalogCmdOutput]{
 		if strings.TrimSpace(in.Dir) == "" {
 			return CatalogCmdOutput{}, errors.New("dir required")
 		}
+		if in.Kind != "" {
+			valid := false
+			for _, k := range AllKinds() {
+				if Kind(in.Kind) == k {
+					valid = true
+					break
+				}
+			}
+			if !valid {
+				return CatalogCmdOutput{}, fmt.Errorf("invalid --kind %q: valid kinds are: %s", in.Kind, strings.Join(func() []string {
+					kinds := make([]string, len(AllKinds()))
+					for i, k := range AllKinds() {
+						kinds[i] = string(k)
+					}
+					return kinds
+				}(), ", "))
+			}
+		}
 		db, err := d.OpenDB(ctx)
 		if err != nil {
 			return CatalogCmdOutput{}, err
diff --git a/internal/lore/catalog_test.go b/internal/lore/catalog_test.go
index 02d7a89..3b1e2d7 100644
--- a/internal/lore/catalog_test.go
+++ b/internal/lore/catalog_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
@@ -180,3 +181,32 @@ func TestCatalog_NonExistentDir(t *testing.T) {
 		t.Error("Catalog on non-existent dir should return error")
 	}
 }
+
+func TestCatalog_InvalidKind(t *testing.T) {
+	ctx := context.Background()
+	db := openTestDB(t, "catalog-kind")
+
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "note.md"), []byte("# Note\n\nContent."), 0o600); err != nil {
+		t.Fatalf("write note.md: %v", err)
+	}
+
+	_, err := Catalog(ctx, db, &CatalogParams{
+		Dir:       dir,
+		ProjectID: "catalog-kind",
+		Kind:      "not-a-real-kind",
+	})
+	if err == nil {
+		t.Fatal("Catalog with invalid --kind should return error")
+	}
+	// Verify error mentions valid kinds.
+	for _, k := range AllKinds() {
+		if !strings.Contains(err.Error(), string(k)) {
+			t.Errorf("error %q does not contain valid kind %q", err.Error(), k)
+		}
+	}
+	// Verify error mentions the invalid kind.
+	if !strings.Contains(err.Error(), "not-a-real-kind") {
+		t.Errorf("error %q does not contain the invalid kind", err.Error())
+	}
+}