diff --git a/swagger.go b/swagger.go
index 9c0cb27..3cfc20e 100644
--- a/swagger.go
+++ b/swagger.go
@@ -11,6 +11,7 @@ import (
 	swaggerFiles "github.com/swaggo/files"
 	ginSwagger "github.com/swaggo/gin-swagger"
 	"github.com/swaggo/swag"
+	"slices"
 )
 
 // swaggerSeq provides unique instance names so multiple Engine instances
@@ -26,6 +27,13 @@ type swaggerSpec struct {
 	doc     string
 }
 
+func newSwaggerSpec(builder *SpecBuilder, groups []RouteGroup) *swaggerSpec {
+	return &swaggerSpec{
+		builder: builder,
+		groups:  slices.Clone(groups),
+	}
+}
+
 // ReadDoc returns the OpenAPI 3.1 JSON document for this spec.
 func (s *swaggerSpec) ReadDoc() string {
 	s.once.Do(func() {
@@ -41,24 +49,21 @@ func (s *swaggerSpec) ReadDoc() string {
 
 // registerSwagger mounts the Swagger UI and doc.json endpoint.
 func registerSwagger(g *gin.Engine, title, description, version, graphqlPath, termsOfService, contactName, contactURL, contactEmail string, servers []string, licenseName, licenseURL, externalDocsDescription, externalDocsURL string, groups []RouteGroup) {
-	spec := &swaggerSpec{
-		builder: &SpecBuilder{
-			Title:                   title,
-			Description:             description,
-			Version:                 version,
-			GraphQLPath:             graphqlPath,
-			TermsOfService:          termsOfService,
-			ContactName:             contactName,
-			ContactURL:              contactURL,
-			ContactEmail:            contactEmail,
-			Servers:                 servers,
-			LicenseName:             licenseName,
-			LicenseURL:              licenseURL,
-			ExternalDocsDescription: externalDocsDescription,
-			ExternalDocsURL:         externalDocsURL,
-		},
-		groups: groups,
-	}
+	spec := newSwaggerSpec(&SpecBuilder{
+		Title:                   title,
+		Description:             description,
+		Version:                 version,
+		GraphQLPath:             graphqlPath,
+		TermsOfService:          termsOfService,
+		ContactName:             contactName,
+		ContactURL:              contactURL,
+		ContactEmail:            contactEmail,
+		Servers:                 servers,
+		LicenseName:             licenseName,
+		LicenseURL:              licenseURL,
+		ExternalDocsDescription: externalDocsDescription,
+		ExternalDocsURL:         externalDocsURL,
+	}, groups)
 	name := fmt.Sprintf("swagger_%d", swaggerSeq.Add(1))
 	swag.Register(name, spec)
 	g.GET("/swagger/*any", ginSwagger.WrapHandler(swaggerFiles.NewHandler(), ginSwagger.InstanceName(name)))
diff --git a/swagger_internal_test.go b/swagger_internal_test.go
new file mode 100644
index 0000000..70260b7
--- /dev/null
+++ b/swagger_internal_test.go
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: EUPL-1.2
+
+package api
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+)
+
+type swaggerSnapshotGroup struct {
+	name     string
+	basePath string
+	descs    []RouteDescription
+}
+
+func (g *swaggerSnapshotGroup) Name() string                      { return g.name }
+func (g *swaggerSnapshotGroup) BasePath() string                  { return g.basePath }
+func (g *swaggerSnapshotGroup) RegisterRoutes(_ *gin.RouterGroup) {}
+func (g *swaggerSnapshotGroup) Describe() []RouteDescription {
+	return g.descs
+}
+
+func TestSwaggerSpec_ReadDoc_Good_SnapshotsGroups(t *testing.T) {
+	original := &swaggerSnapshotGroup{
+		name:     "first",
+		basePath: "/first",
+		descs: []RouteDescription{
+			{
+				Method:  "GET",
+				Path:    "/ping",
+				Summary: "First group",
+				Response: map[string]any{
+					"type": "string",
+				},
+			},
+		},
+	}
+	replacement := &swaggerSnapshotGroup{
+		name:     "second",
+		basePath: "/second",
+		descs: []RouteDescription{
+			{
+				Method:  "GET",
+				Path:    "/pong",
+				Summary: "Second group",
+				Response: map[string]any{
+					"type": "string",
+				},
+			},
+		},
+	}
+
+	groups := []RouteGroup{original}
+	spec := newSwaggerSpec(&SpecBuilder{
+		Title:   "Test",
+		Version: "1.0.0",
+	}, groups)
+
+	groups[0] = replacement
+
+	var doc map[string]any
+	if err := json.Unmarshal([]byte(spec.ReadDoc()), &doc); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+
+	paths := doc["paths"].(map[string]any)
+	if _, ok := paths["/first/ping"]; !ok {
+		t.Fatal("expected original group path to remain in the spec")
+	}
+	if _, ok := paths["/second/pong"]; ok {
+		t.Fatal("did not expect mutated group path to leak into the spec")
+	}
+}