diff --git a/cmd/changelog-check/main.go b/cmd/changelog-check/main.go
new file mode 100644
index 0000000..8b3fcef
--- /dev/null
+++ b/cmd/changelog-check/main.go
@@ -0,0 +1,47 @@
+package main
+
+import (
+	"io"
+	"log"
+	"os"
+
+	"github.com/hashicorp/go-changelog"
+)
+
+func main() {
+	var err error
+
+	// default to reading from stdin
+	r := os.Stdin
+
+	// read from file arg instead if provided
+	// TODO: add --help text for [file] arg handling
+	filepath := ""
+	if len(os.Args) > 1 {
+		filepath = os.Args[1]
+		r, err = os.Open(filepath)
+		if err != nil {
+			log.Fatalf("error opening %s", filepath)
+			os.Exit(1)
+		}
+	}
+
+	b, err := io.ReadAll(r)
+	if err != nil {
+		if filepath != "" {
+			log.Fatalf("error reading from %s", filepath)
+		} else {
+			log.Fatalf("error reading from stdin")
+		}
+		os.Exit(1)
+	}
+
+	entry := changelog.Entry{
+		Body: string(b),
+	}
+
+	if err := entry.Validate(); err != nil {
+		log.Fatalf(err.Error())
+		os.Exit(1)
+	}
+}
diff --git a/cmd/changelog-pr-body-check/main.go b/cmd/changelog-pr-body-check/main.go
index e2c701c..0f59cea 100644
--- a/cmd/changelog-pr-body-check/main.go
+++ b/cmd/changelog-pr-body-check/main.go
@@ -48,60 +48,57 @@ func main() {
 		log.Fatalf("Error retrieving pull request github.com/"+
 			"%s/%s/%d: %s", owner, repo, prNo, err)
 	}
+
 	entry := changelog.Entry{
 		Issue: pr,
 		Body:  pullRequest.GetBody(),
 	}
-	notes := changelog.NotesFromEntry(entry)
-	if len(notes) < 1 {
-		log.Printf("no changelog entry found in %s: %s", entry.Issue,
-			string(entry.Body))
-		body := "Oops! It looks like no changelog entry is attached to" +
-			" this PR. Please include a release note block" +
-			" in the PR body, as described in https://github.com/GoogleCloudPlatform/magic-modules/blob/master/.ci/RELEASE_NOTES_GUIDE.md:" +
-			"\n\n~~~\n```release-note:TYPE\nRelease note" +
-			"\n```\n~~~"
-		_, _, err = client.Issues.CreateComment(ctx, owner, repo,
-			prNo, &github.IssueComment{
-				Body: &body,
-			})
-		if err != nil {
-			log.Fatalf("Error creating pull request comment on"+
-				" github.com/%s/%s/%d: %s", owner, repo, prNo,
-				err)
-		}
-		os.Exit(1)
-	}
-	var unknownTypes []string
-	for _, note := range notes {
-		if !changelog.TypeValid(note.Type) {
-			unknownTypes = append(unknownTypes, note.Type)
-		}
-	}
-	if len(unknownTypes) > 0 {
-		log.Printf("unknown changelog types %v", unknownTypes)
-		body := "Oops! It looks like you're using"
-		if len(unknownTypes) == 1 {
-			body += " an"
-		}
-		body += " unknown release-note type"
-		if len(unknownTypes) > 1 {
-			body += "s"
-		}
-		body += " in your changelog entries:"
-		for _, t := range unknownTypes {
-			body += "\n* " + t
-		}
-		body += "\n\nPlease only use the types listed in https://github.com/GoogleCloudPlatform/magic-modules/blob/master/.ci/RELEASE_NOTES_GUIDE.md."
-		_, _, err = client.Issues.CreateComment(ctx, owner, repo,
-			prNo, &github.IssueComment{
-				Body: &body,
-			})
-		if err != nil {
-			log.Fatalf("Error creating pull request comment on"+
-				" github.com/%s/%s/%d: %s", owner, repo, prNo,
-				err)
+
+	if err := entry.Validate(); err != nil {
+		log.Printf("error parsing changelog entry in %s: %s", entry.Issue, err)
+		switch err.Code {
+		case changelog.EntryErrorNotFound:
+			body := "Oops! It looks like no changelog entry is attached to" +
+				" this PR. Please include a release note block" +
+				" in the PR body, as described in https://github.com/GoogleCloudPlatform/magic-modules/blob/master/.ci/RELEASE_NOTES_GUIDE.md:" +
+				"\n\n~~~\n```release-note:TYPE\nRelease note" +
+				"\n```\n~~~"
+			_, _, err := client.Issues.CreateComment(ctx, owner, repo,
+				prNo, &github.IssueComment{
+					Body: &body,
+				})
+			if err != nil {
+				log.Fatalf("Error creating pull request comment on"+
+					" github.com/%s/%s/%d: %s", owner, repo, prNo,
+					err)
+			}
+			os.Exit(1)
+		case changelog.EntryErrorUnknownTypes:
+			unknownTypes := err.Details["unknownTypes"].([]string)
+
+			body := "Oops! It looks like you're using"
+			if len(unknownTypes) == 1 {
+				body += " an"
+			}
+			body += " unknown release-note type"
+			if len(unknownTypes) > 1 {
+				body += "s"
+			}
+			body += " in your changelog entries:"
+			for _, t := range unknownTypes {
+				body += "\n* " + t
+			}
+			body += "\n\nPlease only use the types listed in https://github.com/GoogleCloudPlatform/magic-modules/blob/master/.ci/RELEASE_NOTES_GUIDE.md."
+			_, _, err := client.Issues.CreateComment(ctx, owner, repo,
+				prNo, &github.IssueComment{
+					Body: &body,
+				})
+			if err != nil {
+				log.Fatalf("Error creating pull request comment on"+
+					" github.com/%s/%s/%d: %s", owner, repo, prNo,
+					err)
+			}
+			os.Exit(1)
 		}
-		os.Exit(1)
 	}
 }
diff --git a/entry.go b/entry.go
index 4a0a59f..aef06b3 100644
--- a/entry.go
+++ b/entry.go
@@ -39,6 +39,54 @@ type EntryList struct {
 	es []*Entry
 }
 
+type EntryErrorCode string
+
+const (
+	EntryErrorNotFound     EntryErrorCode = "NOT_FOUND"
+	EntryErrorUnknownTypes EntryErrorCode = "UNKNOWN_TYPES"
+)
+
+type EntryValidationError struct {
+	message string
+	Code    EntryErrorCode
+	Details map[string]interface{}
+}
+
+func (e *EntryValidationError) Error() string {
+	return e.message
+}
+
+// Validates that an Entry body contains properly formatted changelog notes
+func (e *Entry) Validate() *EntryValidationError {
+	notes := NotesFromEntry(*e)
+
+	if len(notes) < 1 {
+		return &EntryValidationError{
+			message: fmt.Sprintf("no changelog entry found in: %s", string(e.Body)),
+			Code:    EntryErrorNotFound,
+		}
+	}
+
+	var unknownTypes []string
+	for _, note := range notes {
+		if !TypeValid(note.Type) {
+			unknownTypes = append(unknownTypes, note.Type)
+		}
+	}
+
+	if len(unknownTypes) > 0 {
+		return &EntryValidationError{
+			message: fmt.Sprintf("unknown changelog types %v: please use only the configured changelog entry types: %v", unknownTypes, TypeValues),
+			Code:    EntryErrorUnknownTypes,
+			Details: map[string]interface{}{
+				"unknownTypes": unknownTypes,
+			},
+		}
+	}
+
+	return nil
+}
+
 // NewEntryList returns an EntryList with capacity c
 func NewEntryList(c int) *EntryList {
 	return &EntryList{
@@ -139,7 +187,7 @@ func Diff(repo, ref1, ref2, dir string) (*EntryList, error) {
 	if err := wt.Checkout(&git.CheckoutOptions{
 		Hash:  *rev2,
 		Force: true,
-  }); err != nil {
+	}); err != nil {
 		return nil, fmt.Errorf("could not checkout repository at %s: %w", ref2, err)
 	}
 	entriesAfterFI, err := wt.Filesystem.ReadDir(dir)