diff --git a/cmd/workflow-plugin-eventbus/plugin.go b/cmd/workflow-plugin-eventbus/plugin.go
index 8f2c4cd..f2f9a2b 100644
--- a/cmd/workflow-plugin-eventbus/plugin.go
+++ b/cmd/workflow-plugin-eventbus/plugin.go
@@ -261,6 +261,7 @@ func (p *eventbusPlugin) ContractRegistry() *pb.ContractRegistry {
 			{
 				Kind:          pb.ContractKind_CONTRACT_KIND_STEP,
 				StepType:      "step.eventbus.publish",
+				ConfigMessage: "google.protobuf.Empty",
 				InputMessage:  "workflow.plugin.eventbus.v1.PublishRequest",
 				OutputMessage: "workflow.plugin.eventbus.v1.PublishResponse",
 				Mode:          strict,
@@ -268,6 +269,7 @@ func (p *eventbusPlugin) ContractRegistry() *pb.ContractRegistry {
 			{
 				Kind:          pb.ContractKind_CONTRACT_KIND_STEP,
 				StepType:      "step.eventbus.consume",
+				ConfigMessage: "google.protobuf.Empty",
 				InputMessage:  "workflow.plugin.eventbus.v1.ConsumeRequest",
 				OutputMessage: "workflow.plugin.eventbus.v1.ConsumeResponse",
 				Mode:          strict,
@@ -275,6 +277,7 @@ func (p *eventbusPlugin) ContractRegistry() *pb.ContractRegistry {
 			{
 				Kind:          pb.ContractKind_CONTRACT_KIND_STEP,
 				StepType:      "step.eventbus.ack",
+				ConfigMessage: "google.protobuf.Empty",
 				InputMessage:  "workflow.plugin.eventbus.v1.AckRequest",
 				OutputMessage: "workflow.plugin.eventbus.v1.AckResponse",
 				Mode:          strict,
diff --git a/cmd/workflow-plugin-eventbus/plugin_test.go b/cmd/workflow-plugin-eventbus/plugin_test.go
index 68d8ff6..0c7ef4d 100644
--- a/cmd/workflow-plugin-eventbus/plugin_test.go
+++ b/cmd/workflow-plugin-eventbus/plugin_test.go
@@ -11,6 +11,7 @@ import (
 
 	eventbus "github.com/GoCodeAlone/workflow-plugin-eventbus"
 	eventbusv1 "github.com/GoCodeAlone/workflow-plugin-eventbus/gen"
+	pb "github.com/GoCodeAlone/workflow/plugin/external/proto"
 )
 
 // TestContractRegistry_FileDescriptorSetResolvesEveryContractMessage is the
@@ -64,6 +65,33 @@ func TestContractRegistry_FileDescriptorSetResolvesEveryContractMessage(t *testi
 	}
 }
 
+func TestContractRegistry_StrictStepsDeclareConfigMessage(t *testing.T) {
+	p := &eventbusPlugin{}
+	reg := p.ContractRegistry()
+	if reg == nil {
+		t.Fatal("ContractRegistry returned nil")
+	}
+	emptyConfigSteps := map[string]bool{
+		"step.eventbus.publish": true,
+		"step.eventbus.consume": true,
+		"step.eventbus.ack":     true,
+	}
+	for _, c := range reg.Contracts {
+		if c.Kind != pb.ContractKind_CONTRACT_KIND_STEP {
+			continue
+		}
+		if c.Mode != pb.ContractMode_CONTRACT_MODE_STRICT_PROTO {
+			continue
+		}
+		if c.ConfigMessage == "" {
+			t.Fatalf("strict step %q must declare config message so Workflow can encode TypedConfig", c.StepType)
+		}
+		if emptyConfigSteps[c.StepType] && c.ConfigMessage != "google.protobuf.Empty" {
+			t.Fatalf("strict step %q config message = %q, want google.protobuf.Empty", c.StepType, c.ConfigMessage)
+		}
+	}
+}
+
 func registerMessages(t *testing.T, types *protoregistry.Types, messages protoreflect.MessageDescriptors) {
 	t.Helper()
 	for i := 0; i < messages.Len(); i++ {
diff --git a/plugin.contracts.json b/plugin.contracts.json
index 107fe38..922f570 100644
--- a/plugin.contracts.json
+++ b/plugin.contracts.json
@@ -23,6 +23,7 @@
             "kind": "step",
             "type": "step.eventbus.publish",
             "mode": "strict_proto",
+            "config": "google.protobuf.Empty",
             "input": "workflow.plugin.eventbus.v1.PublishRequest",
             "output": "workflow.plugin.eventbus.v1.PublishResponse"
         },
@@ -30,6 +31,7 @@
             "kind": "step",
             "type": "step.eventbus.consume",
             "mode": "strict_proto",
+            "config": "google.protobuf.Empty",
             "input": "workflow.plugin.eventbus.v1.ConsumeRequest",
             "output": "workflow.plugin.eventbus.v1.ConsumeResponse"
         },
@@ -37,6 +39,7 @@
             "kind": "step",
             "type": "step.eventbus.ack",
             "mode": "strict_proto",
+            "config": "google.protobuf.Empty",
             "input": "workflow.plugin.eventbus.v1.AckRequest",
             "output": "workflow.plugin.eventbus.v1.AckResponse"
         },