diff --git a/README.md b/README.md
index 9052de3f..2ea85c46 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ can import packages from `gnostic-models` instead of `gnostic`.
 
 [google/gnostic-grpc](https://github.com/google/gnostic-grpc) contains a
 gnostic plugin that can generate an annotated Protocol Buffer description of an
-API that, when transcode, produces an API that conforms to a specified OpenAPI
+API that, when transcoded, produces an API that conforms to a specified OpenAPI
 document. To go from protobuf to OpenAPI, see the
 [protoc-gen-openapi](cmd/protoc-gen-openapi) tool in this project.
 
@@ -69,12 +69,12 @@ and later.
         git clone https://github.com/google/gnostic
         cd gnostic
 
-2.  Verify that you have a local installation of `protoc`. You can get protoc
+2.  Verify that you have a local installation of `protoc`. You can get `protoc`
     [here](https://github.com/protocolbuffers/protobuf).
 
 3.  Build **gnostic** with `make`. This uses
     [go generate](https://blog.golang.org/generate) to build support code
-    including code generated by `protoc` and the Go protoc plugin, which is
+    including code generated by `protoc` and the Go `protoc` plugin, which is
     automatically downloaded from
     [github.com/golang/protobuf](https://github.com/golang/protobuf) by the
     [COMPILE-PROTOS.sh](COMPILE-PROTOS.sh) script. This also builds all plugins
diff --git a/generate-gnostic/generate-extension.go b/generate-gnostic/generate-extension.go
index b8456185..27270d30 100644
--- a/generate-gnostic/generate-extension.go
+++ b/generate-gnostic/generate-extension.go
@@ -281,6 +281,9 @@ func generateExtension(schemaFile string, outDir string) error {
 		return err
 	}
 	err = exec.Command(runtime.GOROOT()+"/bin/gofmt", "-w", goFilename).Run()
+	if err != nil {
+		return err
+	}
 
 	// generate the main file.
 
diff --git a/generate-gnostic/generate-extension_test.go b/generate-gnostic/generate-extension_test.go
index 9ec62be5..344848f8 100644
--- a/generate-gnostic/generate-extension_test.go
+++ b/generate-gnostic/generate-extension_test.go
@@ -16,6 +16,9 @@ func TestErrorExtensionGeneratorUnsupportedPrimitive(t *testing.T) {
 		"test/x-unsupportedprimitives.json",
 		"--out_dir=/tmp",
 	).Output()
+	if err != nil {
+		t.Fatalf("error executing generate-gnostic: %v", err)
+	}
 
 	outputFile := "x-unsupportedprimitives.errors"
 	_ = ioutil.WriteFile(outputFile, output, 0644)
@@ -38,6 +41,9 @@ func TestErrorExtensionGeneratorNameCollision(t *testing.T) {
 		"test/x-extension-name-collision.json",
 		"--out_dir=/tmp",
 	).Output()
+	if err != nil {
+		t.Fatalf("error executing generate-gnostic: %v", err)
+	}
 
 	outputFile := "x-extension-name-collision.errors"
 	_ = ioutil.WriteFile(outputFile, output, 0644)
diff --git a/jsonwriter/writer.go b/jsonwriter/writer.go
index cc0eaccb..7da769c5 100644
--- a/jsonwriter/writer.go
+++ b/jsonwriter/writer.go
@@ -18,19 +18,15 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"strings"
+	"strconv"
 
 	"gopkg.in/yaml.v3"
 )
 
-const indentation = "  "
-
-// basic escaping, will need to be improved or replaced
-func escape(s string) string {
-	s = strings.Replace(s, "\n", "\\n", -1)
-	s = strings.Replace(s, "\"", "\\\"", -1)
-	return s
-}
+const (
+	indentation = "  "
+	null        = "null"
+)
 
 type writer struct {
 	b bytes.Buffer
@@ -85,15 +81,15 @@ func (w *writer) writeScalar(node *yaml.Node, indent string) {
 	}
 	switch node.Tag {
 	case "!!str":
-		w.writeString("\"")
-		w.writeString(escape(node.Value))
-		w.writeString("\"")
+		w.writeString(strconv.Quote(node.Value))
 	case "!!int":
 		w.writeString(node.Value)
 	case "!!float":
 		w.writeString(node.Value)
 	case "!!bool":
 		w.writeString(node.Value)
+	case "!!null":
+		w.writeString(null)
 	}
 }
 
diff --git a/jsonwriter/writer_test.go b/jsonwriter/writer_test.go
index b714e609..28f28a29 100644
--- a/jsonwriter/writer_test.go
+++ b/jsonwriter/writer_test.go
@@ -37,6 +37,8 @@ func TestMarshal(t *testing.T) {
 		scalarBoolTestCase(),
 		scalarFloatTestCase(),
 		scalarIntTestCase(),
+		scalarStringTestCase(),
+		scalarNullTestCase(),
 		sequenceStringArrayTestCase(),
 		sequenceBoolArrayTestCase(),
 		sequenceFloatArrayTestCase(),
@@ -88,6 +90,22 @@ func scalarFloatTestCase() *MarshalTestCase {
 	}
 }
 
+func scalarStringTestCase() *MarshalTestCase {
+	return &MarshalTestCase{
+		Name:     "scalar string",
+		Node:     compiler.NewScalarNodeForString("a\\b\nc\""),
+		Expected: "\"a\\\\b\\nc\\\"\"\n",
+	}
+}
+
+func scalarNullTestCase() *MarshalTestCase {
+	return &MarshalTestCase{
+		Name:     "scalar null",
+		Node:     compiler.NewNullNode(),
+		Expected: "null\n",
+	}
+}
+
 func scalarIntTestCase() *MarshalTestCase {
 	return &MarshalTestCase{
 		Name:     "scalar int",
diff --git a/metrics/vocabulary/vocabulary.go b/metrics/vocabulary/vocabulary.go
index cbca53f9..a0b01aa7 100644
--- a/metrics/vocabulary/vocabulary.go
+++ b/metrics/vocabulary/vocabulary.go
@@ -43,10 +43,11 @@ func WriteCSV(v *metrics.Vocabulary, filename string) error {
 		filename = "vocabulary-operation.csv"
 	}
 	f4, ferror := os.Create(filename)
-	defer f4.Close()
 	if ferror != nil {
 		return ferror
 	}
+	defer f4.Close()
+
 	for _, s := range v.Schemas {
 		temp := fmt.Sprintf("%s,\"%s\",%d\n", "schemas", s.Word, int(s.Count))
 		f4.WriteString(temp)
diff --git a/openapiv3/README.md b/openapiv3/README.md
index 0b015bce..5184f7fa 100644
--- a/openapiv3/README.md
+++ b/openapiv3/README.md
@@ -7,13 +7,13 @@ Gnostic applications and plugins can use OpenAPIv3.proto to generate Protocol
 Buffer support code for their preferred languages.
 
 OpenAPIv3.go is used by Gnostic to read JSON and YAML OpenAPI descriptions into
-the Protocol Buffer-based datastructures generated from OpenAPIv3.proto.
+the Protocol Buffer-based data structures generated from OpenAPIv3.proto.
 
 OpenAPIv3.proto and OpenAPIv3.go are generated by the Gnostic compiler
-generator, and OpenAPIv3.pb.go is generated by protoc, the Protocol Buffer
-compiler, and protoc-gen-go, the Protocol Buffer Go code generation plugin.
+generator, and OpenAPIv3.pb.go is generated by `protoc`, the Protocol Buffer
+compiler, and `protoc-gen-go`, the Protocol Buffer Go code generation plugin.
 
-openapi-3.1.json is a JSON schema for OpenAPI 3.1 that is automatically
+`openapi-3.1.json` is a JSON schema for OpenAPI 3.1 that is automatically
 generated from the OpenAPI 3.1 specification. It is not an official JSON Schema
 for OpenAPI.
 
diff --git a/plugins/gnostic-analyze/summarize/main.go b/plugins/gnostic-analyze/summarize/main.go
index 7056ee82..746d320f 100644
--- a/plugins/gnostic-analyze/summarize/main.go
+++ b/plugins/gnostic-analyze/summarize/main.go
@@ -32,6 +32,9 @@ var stats []statistics.DocumentStatistics
 
 // walker is called for each summary file found.
 func walker(p string, info os.FileInfo, err error) error {
+	if err != nil {
+		return err
+	}
 	basename := path.Base(p)
 	if basename != "summary.json" {
 		return nil