diff --git a/cmd/wasm/functions.go b/cmd/wasm/functions.go
index c165f45..bbd4ffe 100644
--- a/cmd/wasm/functions.go
+++ b/cmd/wasm/functions.go
@@ -10,7 +10,6 @@ import (
 
 	"github.com/speakeasy-api/jsonpath/pkg/jsonpath"
 	"github.com/speakeasy-api/jsonpath/pkg/jsonpath/config"
-	"github.com/speakeasy-api/jsonpath/pkg/jsonpath/token"
 	"github.com/speakeasy-api/openapi/overlay"
 	"gopkg.in/yaml.v3"
 )
@@ -34,7 +33,6 @@ func CalculateOverlay(originalYAML, targetYAML, existingOverlay string) (string,
 	if err != nil {
 		return "", fmt.Errorf("failed to parse overlay schema in CalculateOverlay: %w", err)
 	}
-	existingOverlayDocument.JSONPathVersion = "rfc9535" // force this in the playground.
 	// now modify the original using the existing overlay
 	err = existingOverlayDocument.ApplyTo(&orig)
 	if err != nil {
@@ -46,8 +44,16 @@ func CalculateOverlay(originalYAML, targetYAML, existingOverlay string) (string,
 		return "", fmt.Errorf("failed to compare schemas: %w", err)
 	}
 	// special case, is there only one action and it targets the same as the last overlayDocument.Actions item entry, we'll just replace it.
-	if len(newOverlay.Actions) == 1 && len(existingOverlayDocument.Actions) > 0 && newOverlay.Actions[0].Target == existingOverlayDocument.Actions[len(existingOverlayDocument.Actions)-1].Target {
-		existingOverlayDocument.Actions[len(existingOverlayDocument.Actions)-1] = newOverlay.Actions[0]
+	lastAction := len(existingOverlayDocument.Actions) - 1
+	if len(newOverlay.Actions) == 1 && lastAction >= 0 && newOverlay.Actions[0].Target == existingOverlayDocument.Actions[lastAction].Target {
+		prev := &existingOverlayDocument.Actions[lastAction]
+		next := &newOverlay.Actions[0]
+		// If both are sequence updates, concatenate content rather than replacing
+		if prev.Update.Kind == yaml.SequenceNode && next.Update.Kind == yaml.SequenceNode {
+			prev.Update.Content = append(prev.Update.Content, next.Update.Content...)
+		} else {
+			existingOverlayDocument.Actions[lastAction] = *next
+		}
 	} else {
 		// Otherwise, we'll just append the new overlay to the existing overlay
 		existingOverlayDocument.Actions = append(existingOverlayDocument.Actions, newOverlay.Actions...)
@@ -115,16 +121,8 @@ func ApplyOverlay(originalYAML, overlayYAML string) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("failed to validate overlay schema in ApplyOverlay: %w", err)
 	}
-	hasFilterExpression := false
-	// check to see if we have an overlay with an error, or a partial overlay: i.e. any overlay actions are missing an update or remove
+	// If an action has a valid target but no operation (update, remove, or copy), return query results for the target path (explorer mode).
 	for i, action := range overlay.Actions {
-		tokenized := token.NewTokenizer(action.Target, config.WithPropertyNameExtension()).Tokenize()
-		for _, tok := range tokenized {
-			if tok.Token == token.FILTER {
-				hasFilterExpression = true
-				break
-			}
-		}
 		parsed, pathErr := jsonpath.NewPath(action.Target, config.WithPropertyNameExtension())
 
 		var node *yaml.Node
@@ -136,7 +134,7 @@ func ApplyOverlay(originalYAML, overlayYAML string) (string, error) {
 
 			return applyOverlayJSONPathError(pathErr, node)
 		}
-		if reflect.ValueOf(action.Update).IsZero() && action.Remove == false {
+		if reflect.ValueOf(action.Update).IsZero() && !action.Remove && action.Copy == "" {
 			result := parsed.Query(&orig)
 
 			node, err = lookupOverlayActionTargetNode(overlayYAML, i)
@@ -147,10 +145,6 @@ func ApplyOverlay(originalYAML, overlayYAML string) (string, error) {
 			return applyOverlayJSONPathIncomplete(result, node)
 		}
 	}
-	if hasFilterExpression && overlay.JSONPathVersion != "rfc9535" {
-		return "", fmt.Errorf("invalid overlay schema: must have `x-speakeasy-jsonpath: rfc9535`")
-	}
-
 	err = overlay.ApplyTo(&orig)
 	if err != nil {
 		return "", fmt.Errorf("failed to apply overlay: %w", err)
diff --git a/go.mod b/go.mod
index 662f435..43815de 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.24.3
 
 require (
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2
-	github.com/speakeasy-api/openapi v1.16.2
+	github.com/speakeasy-api/openapi v1.18.1
 	github.com/stretchr/testify v1.11.1
 	gopkg.in/yaml.v3 v3.0.1
 )
diff --git a/go.sum b/go.sum
index 5f39949..98c865c 100644
--- a/go.sum
+++ b/go.sum
@@ -28,8 +28,8 @@ github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR
 github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
 github.com/sergi/go-diff v1.1.0 h1:we8PVUC3FE2uYfodKH/nBHMSetSfHDR6scGdBi+erh0=
 github.com/sergi/go-diff v1.1.0/go.mod h1:STckp+ISIX8hZLjrqAeVduY0gWCT9IjLuqbuNXdaHfM=
-github.com/speakeasy-api/openapi v1.16.2 h1:ntN57Z4isk3jfckYf7L957/2JtZazpfm8qg76pPlpR0=
-github.com/speakeasy-api/openapi v1.16.2/go.mod h1:aiVj+JnirrwZDtKegt0hQrj/ixl3v17EkN2YGnTuSro=
+github.com/speakeasy-api/openapi v1.18.1 h1:re8tzO8u5U8q33z9mm1UiuiGo9fLrHJgk238WKYdIZM=
+github.com/speakeasy-api/openapi v1.18.1/go.mod h1:aiVj+JnirrwZDtKegt0hQrj/ixl3v17EkN2YGnTuSro=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
diff --git a/pkg/jsonpath/jsonpath.go b/pkg/jsonpath/jsonpath.go
index d5c8a5b..82c5122 100644
--- a/pkg/jsonpath/jsonpath.go
+++ b/pkg/jsonpath/jsonpath.go
@@ -12,7 +12,7 @@ func NewPath(input string, opts ...config.Option) (*JSONPath, error) {
 	tokens := tokenizer.Tokenize()
 	for i := 0; i < len(tokens); i++ {
 		if tokens[i].Token == token.ILLEGAL {
-			return nil, fmt.Errorf(tokenizer.ErrorString(&tokens[i], "unexpected token"))
+			return nil, fmt.Errorf("%s", tokenizer.ErrorString(&tokens[i], "unexpected token"))
 		}
 	}
 	parser := newParserPrivate(tokenizer, tokens, opts...)
diff --git a/pkg/jsonpath/token/token_test.go b/pkg/jsonpath/token/token_test.go
index d8c7931..c5e5a16 100644
--- a/pkg/jsonpath/token/token_test.go
+++ b/pkg/jsonpath/token/token_test.go
@@ -610,12 +610,12 @@ func TestTokenizer_categorize(t *testing.T) {
 				if token.Token == ILLEGAL {
 					foundIllegal = true
 					if !tc.illegal {
-						t.Errorf(tokenizer.ErrorString(&token, "Illegal Token"))
+						t.Errorf("%s", tokenizer.ErrorString(&token, "Illegal Token"))
 					}
 				}
 			}
 			if tc.illegal && !foundIllegal {
-				t.Errorf(tokenizer.ErrorTokenString(&tokenizedJsonPath[0], "Expected an illegal token"))
+				t.Errorf("%s", tokenizer.ErrorTokenString(&tokenizedJsonPath[0], "Expected an illegal token"))
 			}
 
 			if tc.simple && foundIllegal {
@@ -632,12 +632,12 @@ func TestTokenizer_categorize(t *testing.T) {
 						}
 					}
 					if !simple {
-						t.Errorf(tokenizer.ErrorString(&token, "Expected a simple path, but found a non-simple token"))
+						t.Errorf("%s", tokenizer.ErrorString(&token, "Expected a simple path, but found a non-simple token"))
 					}
 				}
 			}
 			if !tc.simple && tokenizedJsonPath.IsSimple() {
-				t.Errorf(tokenizer.ErrorTokenString(&tokenizedJsonPath[0], "Expected a non-simple path, but found it was simple"))
+				t.Errorf("%s", tokenizer.ErrorTokenString(&tokenizedJsonPath[0], "Expected a non-simple path, but found it was simple"))
 			}
 		})
 	}
diff --git a/web/src/assets/wasm/lib.wasm b/web/src/assets/wasm/lib.wasm
index ea407a5..a5e02ea 100755
Binary files a/web/src/assets/wasm/lib.wasm and b/web/src/assets/wasm/lib.wasm differ
diff --git a/web/src/defaults.ts b/web/src/defaults.ts
index 45a7445..0d7d78c 100644
--- a/web/src/defaults.ts
+++ b/web/src/defaults.ts
@@ -817,16 +817,22 @@ components:
 `;
 
 export const blankOverlay = `overlay: 1.1.0
-x-speakeasy-jsonpath: rfc9535
 info:
     title: example overlay
     version: 0.0.0
-actions: 
+actions:
   - target: $.info.description
-    update: Hello World`;
+    description: Update the API description
+    update: Hello World
+  - target: $.components.schemas
+    description: Create an empty schema to copy into
+    update:
+      PetSummary: {}
+  - target: $.components.schemas.PetSummary
+    description: Copy the Pet schema into PetSummary
+    copy: $.components.schemas.Pet`;
 
 export const emptyOverlay = `overlay: 1.1.0
-x-speakeasy-jsonpath: rfc9535
 info:
     title: example overlay
     version: 0.0.0