diff --git a/plugins/pluginrpc-gen/fixtures/foo.go b/plugins/pluginrpc-gen/fixtures/foo.go
index 4e73fc1..fcb2b62 100644
--- a/plugins/pluginrpc-gen/fixtures/foo.go
+++ b/plugins/pluginrpc-gen/fixtures/foo.go
@@ -6,12 +6,15 @@ type wobble struct {
 	Inception *wobble
 }
 
+// Fooer is an empty interface used for tests.
 type Fooer interface{}
 
+// Fooer2 is an interface used for tests.
 type Fooer2 interface {
 	Foo()
 }
 
+// Fooer3 is an interface used for tests.
 type Fooer3 interface {
 	Foo()
 	Bar(a string)
@@ -21,14 +24,17 @@ type Fooer3 interface {
 	Wiggle() (w wobble)
 }
 
+// Fooer4 is an interface used for tests.
 type Fooer4 interface {
 	Foo() error
 }
 
+// Bar is an interface used for tests.
 type Bar interface {
 	Boo(a string, b string) (s string, err error)
 }
 
+// Fooer5 is an interface used for tests.
 type Fooer5 interface {
 	Foo()
 	Bar
diff --git a/plugins/pluginrpc-gen/main.go b/plugins/pluginrpc-gen/main.go
index 2130af1..772984c 100644
--- a/plugins/pluginrpc-gen/main.go
+++ b/plugins/pluginrpc-gen/main.go
@@ -72,7 +72,7 @@ func main() {
 		InterfaceType string
 		RPCName       string
 		BuildTags     map[string]struct{}
-		*parsedPkg
+		*ParsedPkg
 	}{toLower(*typeName), *rpcName, flBuildTags.GetValues(), pkg}
 	var buf bytes.Buffer
 
diff --git a/plugins/pluginrpc-gen/parser.go b/plugins/pluginrpc-gen/parser.go
index b84fef0..3adeb49 100644
--- a/plugins/pluginrpc-gen/parser.go
+++ b/plugins/pluginrpc-gen/parser.go
@@ -9,18 +9,20 @@ import (
 	"reflect"
 )
 
-var ErrBadReturn = errors.New("found return arg with no name: all args must be named")
+var errBadReturn = errors.New("found return arg with no name: all args must be named")
 
-type ErrUnexpectedType struct {
+type errUnexpectedType struct {
 	expected string
 	actual   interface{}
 }
 
-func (e ErrUnexpectedType) Error() string {
+func (e errUnexpectedType) Error() string {
 	return fmt.Sprintf("got wrong type expecting %s, got: %v", e.expected, reflect.TypeOf(e.actual))
 }
 
-type parsedPkg struct {
+// ParsedPkg holds information about a package that has been parsed,
+// its name and the list of functions.
+type ParsedPkg struct {
 	Name      string
 	Functions []function
 }
@@ -41,14 +43,14 @@ func (a *arg) String() string {
 	return a.Name + " " + a.ArgType
 }
 
-// Parses the given file for an interface definition with the given name
-func Parse(filePath string, objName string) (*parsedPkg, error) {
+// Parse parses the given file for an interface definition with the given name.
+func Parse(filePath string, objName string) (*ParsedPkg, error) {
 	fs := token.NewFileSet()
 	pkg, err := parser.ParseFile(fs, filePath, nil, parser.AllErrors)
 	if err != nil {
 		return nil, err
 	}
-	p := &parsedPkg{}
+	p := &ParsedPkg{}
 	p.Name = pkg.Name.Name
 	obj, exists := pkg.Scope.Objects[objName]
 	if !exists {
@@ -59,11 +61,11 @@ func Parse(filePath string, objName string) (*parsedPkg, error) {
 	}
 	spec, ok := obj.Decl.(*ast.TypeSpec)
 	if !ok {
-		return nil, ErrUnexpectedType{"*ast.TypeSpec", obj.Decl}
+		return nil, errUnexpectedType{"*ast.TypeSpec", obj.Decl}
 	}
 	iface, ok := spec.Type.(*ast.InterfaceType)
 	if !ok {
-		return nil, ErrUnexpectedType{"*ast.InterfaceType", spec.Type}
+		return nil, errUnexpectedType{"*ast.InterfaceType", spec.Type}
 	}
 
 	p.Functions, err = parseInterface(iface)
@@ -90,11 +92,11 @@ func parseInterface(iface *ast.InterfaceType) ([]function, error) {
 		case *ast.Ident:
 			spec, ok := f.Obj.Decl.(*ast.TypeSpec)
 			if !ok {
-				return nil, ErrUnexpectedType{"*ast.TypeSpec", f.Obj.Decl}
+				return nil, errUnexpectedType{"*ast.TypeSpec", f.Obj.Decl}
 			}
 			iface, ok := spec.Type.(*ast.InterfaceType)
 			if !ok {
-				return nil, ErrUnexpectedType{"*ast.TypeSpec", spec.Type}
+				return nil, errUnexpectedType{"*ast.TypeSpec", spec.Type}
 			}
 			funcs, err := parseInterface(iface)
 			if err != nil {
@@ -103,7 +105,7 @@ func parseInterface(iface *ast.InterfaceType) ([]function, error) {
 			}
 			functions = append(functions, funcs...)
 		default:
-			return nil, ErrUnexpectedType{"*astFuncType or *ast.Ident", f}
+			return nil, errUnexpectedType{"*astFuncType or *ast.Ident", f}
 		}
 	}
 	return functions, nil
@@ -137,7 +139,7 @@ func parseArgs(fields []*ast.Field) ([]arg, error) {
 	var args []arg
 	for _, f := range fields {
 		if len(f.Names) == 0 {
-			return nil, ErrBadReturn
+			return nil, errBadReturn
 		}
 		for _, name := range f.Names {
 			var typeName string
@@ -147,11 +149,11 @@ func parseArgs(fields []*ast.Field) ([]arg, error) {
 			case *ast.StarExpr:
 				i, ok := argType.X.(*ast.Ident)
 				if !ok {
-					return nil, ErrUnexpectedType{"*ast.Ident", f.Type}
+					return nil, errUnexpectedType{"*ast.Ident", f.Type}
 				}
 				typeName = "*" + i.Name
 			default:
-				return nil, ErrUnexpectedType{"*ast.Ident or *ast.StarExpr", f.Type}
+				return nil, errUnexpectedType{"*ast.Ident or *ast.StarExpr", f.Type}
 			}
 
 			args = append(args, arg{name.Name, typeName})
diff --git a/plugins/pluginrpc-gen/parser_test.go b/plugins/pluginrpc-gen/parser_test.go
index 6c5665f..5a7579c 100644
--- a/plugins/pluginrpc-gen/parser_test.go
+++ b/plugins/pluginrpc-gen/parser_test.go
@@ -22,7 +22,7 @@ func TestParseEmptyInterface(t *testing.T) {
 
 func TestParseNonInterfaceType(t *testing.T) {
 	_, err := Parse(testFixture, "wobble")
-	if _, ok := err.(ErrUnexpectedType); !ok {
+	if _, ok := err.(errUnexpectedType); !ok {
 		t.Fatal("expected type error when parsing non-interface type")
 	}
 }
@@ -109,7 +109,7 @@ func TestParseWithMultipleFuncs(t *testing.T) {
 
 func TestParseWithUnamedReturn(t *testing.T) {
 	_, err := Parse(testFixture, "Fooer4")
-	if !strings.HasSuffix(err.Error(), ErrBadReturn.Error()) {
+	if !strings.HasSuffix(err.Error(), errBadReturn.Error()) {
 		t.Fatalf("expected ErrBadReturn, got %v", err)
 	}
 }