diff --git a/assert/assert.go b/assert/assert.go
index 58772d8..c0279d0 100644
--- a/assert/assert.go
+++ b/assert/assert.go
@@ -97,6 +97,11 @@ var (
 	// These two are our indexing system for default asserter. Note also the
 	// mutex blew. All of this is done to keep client package race detector
 	// cool.
+	//  Production
+	//  Development
+	//  Test
+	//  TestFull
+	//  Debug
 	defAsserter = []Asserter{P, B, T, TF, D}
 	def         defInd
 
@@ -536,6 +541,23 @@ func SetDefault(i defInd) Asserter {
 	return defAsserter[i]
 }
 
+// mapDefInd runtime asserters, that's why test asserts are removed for now.
+var mapDefInd = map[string]defInd{
+	"Production":  Production,
+	"Development": Development,
+	//"Test":        Test,
+	//"TestFull":    TestFull,
+	"Debug": Debug,
+}
+
+func NewDefInd(v string) defInd {
+	ind, found := mapDefInd[v]
+	if !found {
+		return Production
+	}
+	return ind
+}
+
 func combineArgs(format string, a []any) []any {
 	args := make([]any, 1, len(a)+1)
 	args[0] = format
diff --git a/err2_init.go b/err2_init.go
index fa93c34..78438f5 100644
--- a/err2_init.go
+++ b/err2_init.go
@@ -3,11 +3,42 @@ package err2
 import (
 	"flag"
 
+	"github.com/lainio/err2/assert"
 	"github.com/lainio/err2/internal/tracer"
 )
 
+var (
+	// asserter def index flag has following values:
+	//
+	//	Production
+	//	Development
+	//	Test
+	//	TestFull
+	//	Debug
+	asserterFlag flagAsserter
+)
+
 func init() {
 	flag.Var(&tracer.Log, "err2-log", "stream for logging")
 	flag.Var(&tracer.Error, "err2-trace", "stream for error tracing")
 	flag.Var(&tracer.Panic, "err2-panic-trace", "stream for panic tracing")
+	flag.Var(&asserterFlag, "err2-asserter", "asserter: Production, Development, Debug")
+}
+
+type flagAsserter struct {
+	v string
+}
+
+// String is part of the flag interfaces
+func (f *flagAsserter) String() string {
+	return f.v
+}
+
+// Get is part of the flag interfaces, getter.
+func (*flagAsserter) Get() any { return nil }
+
+// Set is part of the flag.Value interface.
+func (f *flagAsserter) Set(flagAsserter string) error {
+	assert.SetDefault(assert.NewDefInd(flagAsserter))
+	return nil
 }