diff --git a/enginetest/internal/action/behavior.go b/enginetest/internal/action/behavior.go
index 59b3666..f0542ff 100644
--- a/enginetest/internal/action/behavior.go
+++ b/enginetest/internal/action/behavior.go
@@ -28,7 +28,7 @@ func Fail(message string) []*Action {
 	}
 }
 
-func (x *Action_Fail) do(s Scope) error {
+func (x *Action_Fail) do(Scope) error {
 	return errors.New(x.Fail)
 }
 
@@ -58,7 +58,7 @@ func ExecuteCommand(c dogma.Command) []*Action {
 }
 
 func (x *Action_ExecuteCommand) do(s Scope) error {
-	s.(executor).ExecuteCommand(fromAny(x.ExecuteCommand))
+	s.(executor).ExecuteCommand(fromAny[dogma.Command](x.ExecuteCommand))
 	return nil
 }
 
@@ -73,7 +73,7 @@ func RecordEvent(e dogma.Message) []*Action {
 }
 
 func (x *Action_RecordEvent) do(s Scope) error {
-	s.(recorder).RecordEvent(fromAny(x.RecordEvent))
+	s.(recorder).RecordEvent(fromAny[dogma.Event](x.RecordEvent))
 	return nil
 }
 
@@ -94,7 +94,7 @@ func ScheduleTimeout(t dogma.Timeout, at time.Time) []*Action {
 
 func (x *Action_ScheduleTimeout) do(s Scope) error {
 	s.(scheduler).ScheduleTimeout(
-		fromAny(x.ScheduleTimeout.Timeout),
+		fromAny[dogma.Timeout](x.ScheduleTimeout.Timeout),
 		x.ScheduleTimeout.At.AsTime(),
 	)
 	return nil
@@ -137,10 +137,10 @@ func toAny(m dogma.Message) *anypb.Any {
 	return x
 }
 
-func fromAny(m *anypb.Any) dogma.Message {
+func fromAny[T dogma.Message](m *anypb.Any) T {
 	x, err := m.UnmarshalNew()
 	if err != nil {
 		panic(err)
 	}
-	return x.(dogma.Message)
+	return x.(T)
 }
diff --git a/enginetest/internal/action/doc.go b/enginetest/internal/action/doc.go
new file mode 100644
index 0000000..1a58c97
--- /dev/null
+++ b/enginetest/internal/action/doc.go
@@ -0,0 +1,3 @@
+// Package action provides a mechanism for triggering arbitrary actions within
+// handlers by encoding the actions to perform within Dogma messages.
+package action
diff --git a/enginetest/internal/testapp/integration.go b/enginetest/internal/testapp/integration.go
index 4db178c..9f05d2c 100644
--- a/enginetest/internal/testapp/integration.go
+++ b/enginetest/internal/testapp/integration.go
@@ -65,7 +65,7 @@ func (x *IntegrationCommandA) MessageDescription() string {
 }
 
 // Validate returns an error if the message is invalid.
-func (x *IntegrationCommandA) Validate() error {
+func (x *IntegrationCommandA) Validate(dogma.CommandValidationScope) error {
 	if x.IsInvalid {
 		return ErrInvalidIntegrationMessage
 	}
@@ -78,7 +78,7 @@ func (x *IntegrationCommandB) MessageDescription() string {
 }
 
 // Validate returns an error if the message is invalid.
-func (x *IntegrationCommandB) Validate() error {
+func (x *IntegrationCommandB) Validate(dogma.CommandValidationScope) error {
 	if x.IsInvalid {
 		return ErrInvalidIntegrationMessage
 	}
@@ -91,7 +91,7 @@ func (x *IntegrationEventA) MessageDescription() string {
 }
 
 // Validate returns an error if the message is invalid.
-func (x *IntegrationEventA) Validate() error {
+func (x *IntegrationEventA) Validate(dogma.EventValidationScope) error {
 	return nil
 }
 
@@ -101,6 +101,6 @@ func (x *IntegrationEventB) MessageDescription() string {
 }
 
 // Validate returns an error if the message is invalid.
-func (x *IntegrationEventB) Validate() error {
+func (x *IntegrationEventB) Validate(dogma.EventValidationScope) error {
 	return nil
 }
diff --git a/enginetest/stubs/message.go b/enginetest/stubs/message.go
index c4343ea..a34202a 100644
--- a/enginetest/stubs/message.go
+++ b/enginetest/stubs/message.go
@@ -3,6 +3,8 @@ package stubs
 import (
 	"errors"
 	"fmt"
+
+	"github.com/dogmatiq/dogma"
 )
 
 // CommandStub is a test implementation of [dogma.Command].
@@ -26,7 +28,7 @@ func (s CommandStub[T]) MessageDescription() string {
 }
 
 // Validate returns a non-nil error if c.Invalid is not empty.
-func (s CommandStub[T]) Validate() error {
+func (s CommandStub[T]) Validate(dogma.CommandValidationScope) error {
 	if s.ValidationError != "" {
 		return errors.New(s.ValidationError)
 	}
@@ -54,7 +56,7 @@ func (s EventStub[T]) MessageDescription() string {
 }
 
 // Validate returns a non-nil error if c.Invalid is not empty.
-func (s EventStub[T]) Validate() error {
+func (s EventStub[T]) Validate(dogma.EventValidationScope) error {
 	if s.ValidationError != "" {
 		return errors.New(s.ValidationError)
 	}
@@ -82,7 +84,7 @@ func (s TimeoutStub[T]) MessageDescription() string {
 }
 
 // Validate returns a non-nil error if c.Invalid is not empty.
-func (s TimeoutStub[T]) Validate() error {
+func (s TimeoutStub[T]) Validate(dogma.TimeoutValidationScope) error {
 	if s.ValidationError != "" {
 		return errors.New(s.ValidationError)
 	}
diff --git a/go.mod b/go.mod
index fa9584f..e1b37bb 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.23
 
 require (
 	github.com/dogmatiq/dapper v0.6.0
-	github.com/dogmatiq/dogma v0.14.3
+	github.com/dogmatiq/dogma v0.15.0
 	github.com/dogmatiq/primo v0.3.1
 	github.com/google/go-cmp v0.6.0
 	google.golang.org/grpc v1.67.1
diff --git a/go.sum b/go.sum
index e022c7c..aa348a5 100644
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,9 @@
 github.com/dogmatiq/dapper v0.6.0 h1:hnWUsjnt3nUiC9hmkPvuxrnMd7fYNz1i+/GS3gOx0Xs=
 github.com/dogmatiq/dapper v0.6.0/go.mod h1:ubRHWzt73s0MsPpGhWvnfW/Z/1YPnrkCsQv6CUOZVEw=
-github.com/dogmatiq/dogma v0.14.3 h1:qwZqU1yqp80toUJcJBdFxLlh6xvlFd7jb7rycmriRUo=
-github.com/dogmatiq/dogma v0.14.3/go.mod h1:9lyVA+6V2+E/exV0IrBOrkUiyFwIATEhv+b0vnB2umQ=
+github.com/dogmatiq/dogma v0.14.4-0.20240926234834-3c0cc27a2ca1 h1:SKhtRnDs7CC3ZNMux7lYCxCFz5ZhmeXjvo7/uMNISLo=
+github.com/dogmatiq/dogma v0.14.4-0.20240926234834-3c0cc27a2ca1/go.mod h1:9lyVA+6V2+E/exV0IrBOrkUiyFwIATEhv+b0vnB2umQ=
+github.com/dogmatiq/dogma v0.15.0 h1:aXOTd2K4wLvlwHc1D9OsFREp0BusNJ9o9KssxURftmg=
+github.com/dogmatiq/dogma v0.15.0/go.mod h1:TF6xisRxQ2RE3JQwFr6MCI4nWLKQQp7KRWXVHOq9K0k=
 github.com/dogmatiq/jumble v0.1.0 h1:Cb3ExfxY+AoUP4G9/sOwoOdYX8o+kOLK8+dhXAry+QA=
 github.com/dogmatiq/jumble v0.1.0/go.mod h1:FCGV2ImXu8zvThxhd4QLstiEdu74vbIVw9bFJSBcKr4=
 github.com/dogmatiq/primo v0.3.1 h1:JSqiCh1ma9CbIVzPf8k1vhzQ2Zn/d/WupzElDoiYZw0=
diff --git a/protobuf/configpb/config.pb.go b/protobuf/configpb/config.pb.go
index 74b4caf..72b3166 100644
--- a/protobuf/configpb/config.pb.go
+++ b/protobuf/configpb/config.pb.go
@@ -146,6 +146,9 @@ type Application struct {
 	GoType string `protobuf:"bytes,2,opt,name=go_type,json=goType,proto3" json:"go_type,omitempty"`
 	// Handlers is the set of handlers within the application.
 	Handlers []*Handler `protobuf:"bytes,3,rep,name=handlers,proto3" json:"handlers,omitempty"`
+	// MessageKinds is a map of each message type's fully-qualified Go type to its
+	// the kind of message it implemented by that type.
+	Messages map[string]MessageKind `protobuf:"bytes,4,rep,name=messages,proto3" json:"messages,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3,enum=dogma.protobuf.MessageKind"`
 }
 
 func (x *Application) Reset() {
@@ -201,6 +204,13 @@ func (x *Application) GetHandlers() []*Handler {
 	return nil
 }
 
+func (x *Application) GetMessages() map[string]MessageKind {
+	if x != nil {
+		return x.Messages
+	}
+	return nil
+}
+
 // Handler is a message handler within an application.
 type Handler struct {
 	state         protoimpl.MessageState
@@ -214,18 +224,12 @@ type Handler struct {
 	GoType string `protobuf:"bytes,2,opt,name=go_type,json=goType,proto3" json:"go_type,omitempty"`
 	// Type is the handler's type.
 	Type HandlerType `protobuf:"varint,3,opt,name=type,proto3,enum=dogma.protobuf.HandlerType" json:"type,omitempty"`
-	// ProducedMessages is the set of messages produced by this handler.
-	//
-	// The keys are the fully-qualified names of the message's Go type and the
-	// value is the kind of message implemented by that type.
-	ProducedMessages map[string]MessageKind `protobuf:"bytes,4,rep,name=produced_messages,json=producedMessages,proto3" json:"produced_messages,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3,enum=dogma.protobuf.MessageKind"`
-	// ConsumedMessages is the set of messages consumed by this handler.
+	// messages is the set of messages produced and consumed by this handler.
 	//
-	// The keys are the fully-qualified names of the message's Go type and the
-	// value is the kind of message implemented by that type.
-	ConsumedMessages map[string]MessageKind `protobuf:"bytes,5,rep,name=consumed_messages,json=consumedMessages,proto3" json:"consumed_messages,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3,enum=dogma.protobuf.MessageKind"`
+	// The keys are the fully-qualified names of the message's Go type.
+	Messages map[string]*MessageUsage `protobuf:"bytes,4,rep,name=messages,proto3" json:"messages,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
 	// IsDisabled indicates whether the handler is disabled.
-	IsDisabled bool `protobuf:"varint,6,opt,name=is_disabled,json=isDisabled,proto3" json:"is_disabled,omitempty"`
+	IsDisabled bool `protobuf:"varint,5,opt,name=is_disabled,json=isDisabled,proto3" json:"is_disabled,omitempty"`
 }
 
 func (x *Handler) Reset() {
@@ -281,23 +285,73 @@ func (x *Handler) GetType() HandlerType {
 	return HandlerType_UNKNOWN_HANDLER_TYPE
 }
 
-func (x *Handler) GetProducedMessages() map[string]MessageKind {
+func (x *Handler) GetMessages() map[string]*MessageUsage {
 	if x != nil {
-		return x.ProducedMessages
+		return x.Messages
 	}
 	return nil
 }
 
-func (x *Handler) GetConsumedMessages() map[string]MessageKind {
+func (x *Handler) GetIsDisabled() bool {
 	if x != nil {
-		return x.ConsumedMessages
+		return x.IsDisabled
 	}
-	return nil
+	return false
 }
 
-func (x *Handler) GetIsDisabled() bool {
+type MessageUsage struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// IsProduced indicates whether the message is produced by the handler.
+	IsProduced bool `protobuf:"varint,2,opt,name=is_produced,json=isProduced,proto3" json:"is_produced,omitempty"`
+	// IsConsumed indicates whether the message is consumed by the handler.
+	IsConsumed bool `protobuf:"varint,3,opt,name=is_consumed,json=isConsumed,proto3" json:"is_consumed,omitempty"`
+}
+
+func (x *MessageUsage) Reset() {
+	*x = MessageUsage{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_msgTypes[2]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *MessageUsage) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageUsage) ProtoMessage() {}
+
+func (x *MessageUsage) ProtoReflect() protoreflect.Message {
+	mi := &file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_msgTypes[2]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageUsage.ProtoReflect.Descriptor instead.
+func (*MessageUsage) Descriptor() ([]byte, []int) {
+	return file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_rawDescGZIP(), []int{2}
+}
+
+func (x *MessageUsage) GetIsProduced() bool {
 	if x != nil {
-		return x.IsDisabled
+		return x.IsProduced
+	}
+	return false
+}
+
+func (x *MessageUsage) GetIsConsumed() bool {
+	if x != nil {
+		return x.IsConsumed
 	}
 	return false
 }
@@ -314,7 +368,7 @@ var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_rawDesc =
 	0x74, 0x69, 0x71, 0x2f, 0x65, 0x6e, 0x67, 0x69, 0x6e, 0x65, 0x6b, 0x69, 0x74, 0x2f, 0x70, 0x72,
 	0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2f, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x70,
 	0x62, 0x2f, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f,
-	0x22, 0x91, 0x01, 0x0a, 0x0b, 0x41, 0x70, 0x70, 0x6c, 0x69, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e,
+	0x22, 0xb2, 0x02, 0x0a, 0x0b, 0x41, 0x70, 0x70, 0x6c, 0x69, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e,
 	0x12, 0x34, 0x0a, 0x08, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x18, 0x01, 0x20, 0x01,
 	0x28, 0x0b, 0x32, 0x18, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f,
 	0x62, 0x75, 0x66, 0x2e, 0x49, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x52, 0x08, 0x69, 0x64,
@@ -323,56 +377,58 @@ var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_rawDesc =
 	0x33, 0x0a, 0x08, 0x68, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x73, 0x18, 0x03, 0x20, 0x03, 0x28,
 	0x0b, 0x32, 0x17, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62,
 	0x75, 0x66, 0x2e, 0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x52, 0x08, 0x68, 0x61, 0x6e, 0x64,
-	0x6c, 0x65, 0x72, 0x73, 0x22, 0xa6, 0x04, 0x0a, 0x07, 0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72,
-	0x12, 0x34, 0x0a, 0x08, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x18, 0x01, 0x20, 0x01,
-	0x28, 0x0b, 0x32, 0x18, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f,
-	0x62, 0x75, 0x66, 0x2e, 0x49, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x52, 0x08, 0x69, 0x64,
-	0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x12, 0x17, 0x0a, 0x07, 0x67, 0x6f, 0x5f, 0x74, 0x79, 0x70,
-	0x65, 0x18, 0x02, 0x20, 0x01, 0x28, 0x09, 0x52, 0x06, 0x67, 0x6f, 0x54, 0x79, 0x70, 0x65, 0x12,
-	0x2f, 0x0a, 0x04, 0x74, 0x79, 0x70, 0x65, 0x18, 0x03, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x1b, 0x2e,
-	0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x48,
-	0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x54, 0x79, 0x70, 0x65, 0x52, 0x04, 0x74, 0x79, 0x70, 0x65,
-	0x12, 0x5a, 0x0a, 0x11, 0x70, 0x72, 0x6f, 0x64, 0x75, 0x63, 0x65, 0x64, 0x5f, 0x6d, 0x65, 0x73,
-	0x73, 0x61, 0x67, 0x65, 0x73, 0x18, 0x04, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x2d, 0x2e, 0x64, 0x6f,
-	0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x48, 0x61, 0x6e,
-	0x64, 0x6c, 0x65, 0x72, 0x2e, 0x50, 0x72, 0x6f, 0x64, 0x75, 0x63, 0x65, 0x64, 0x4d, 0x65, 0x73,
-	0x73, 0x61, 0x67, 0x65, 0x73, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x52, 0x10, 0x70, 0x72, 0x6f, 0x64,
-	0x75, 0x63, 0x65, 0x64, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x12, 0x5a, 0x0a, 0x11,
-	0x63, 0x6f, 0x6e, 0x73, 0x75, 0x6d, 0x65, 0x64, 0x5f, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65,
-	0x73, 0x18, 0x05, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x2d, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e,
-	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72,
-	0x2e, 0x43, 0x6f, 0x6e, 0x73, 0x75, 0x6d, 0x65, 0x64, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65,
-	0x73, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x52, 0x10, 0x63, 0x6f, 0x6e, 0x73, 0x75, 0x6d, 0x65, 0x64,
-	0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x12, 0x1f, 0x0a, 0x0b, 0x69, 0x73, 0x5f, 0x64,
-	0x69, 0x73, 0x61, 0x62, 0x6c, 0x65, 0x64, 0x18, 0x06, 0x20, 0x01, 0x28, 0x08, 0x52, 0x0a, 0x69,
-	0x73, 0x44, 0x69, 0x73, 0x61, 0x62, 0x6c, 0x65, 0x64, 0x1a, 0x60, 0x0a, 0x15, 0x50, 0x72, 0x6f,
-	0x64, 0x75, 0x63, 0x65, 0x64, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x45, 0x6e, 0x74,
-	0x72, 0x79, 0x12, 0x10, 0x0a, 0x03, 0x6b, 0x65, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52,
-	0x03, 0x6b, 0x65, 0x79, 0x12, 0x31, 0x0a, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x18, 0x02, 0x20,
-	0x01, 0x28, 0x0e, 0x32, 0x1b, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74,
-	0x6f, 0x62, 0x75, 0x66, 0x2e, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x4b, 0x69, 0x6e, 0x64,
-	0x52, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x3a, 0x02, 0x38, 0x01, 0x1a, 0x60, 0x0a, 0x15, 0x43,
-	0x6f, 0x6e, 0x73, 0x75, 0x6d, 0x65, 0x64, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x45,
-	0x6e, 0x74, 0x72, 0x79, 0x12, 0x10, 0x0a, 0x03, 0x6b, 0x65, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28,
-	0x09, 0x52, 0x03, 0x6b, 0x65, 0x79, 0x12, 0x31, 0x0a, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x18,
-	0x02, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x1b, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72,
-	0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x4b, 0x69,
-	0x6e, 0x64, 0x52, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x3a, 0x02, 0x38, 0x01, 0x2a, 0x4c, 0x0a,
-	0x0b, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x4b, 0x69, 0x6e, 0x64, 0x12, 0x18, 0x0a, 0x14,
-	0x55, 0x4e, 0x4b, 0x4e, 0x4f, 0x57, 0x4e, 0x5f, 0x4d, 0x45, 0x53, 0x53, 0x41, 0x47, 0x45, 0x5f,
-	0x4b, 0x49, 0x4e, 0x44, 0x10, 0x00, 0x12, 0x0b, 0x0a, 0x07, 0x43, 0x4f, 0x4d, 0x4d, 0x41, 0x4e,
-	0x44, 0x10, 0x01, 0x12, 0x09, 0x0a, 0x05, 0x45, 0x56, 0x45, 0x4e, 0x54, 0x10, 0x02, 0x12, 0x0b,
-	0x0a, 0x07, 0x54, 0x49, 0x4d, 0x45, 0x4f, 0x55, 0x54, 0x10, 0x03, 0x2a, 0x64, 0x0a, 0x0b, 0x48,
-	0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x54, 0x79, 0x70, 0x65, 0x12, 0x18, 0x0a, 0x14, 0x55, 0x4e,
-	0x4b, 0x4e, 0x4f, 0x57, 0x4e, 0x5f, 0x48, 0x41, 0x4e, 0x44, 0x4c, 0x45, 0x52, 0x5f, 0x54, 0x59,
-	0x50, 0x45, 0x10, 0x00, 0x12, 0x0d, 0x0a, 0x09, 0x41, 0x47, 0x47, 0x52, 0x45, 0x47, 0x41, 0x54,
-	0x45, 0x10, 0x01, 0x12, 0x0b, 0x0a, 0x07, 0x50, 0x52, 0x4f, 0x43, 0x45, 0x53, 0x53, 0x10, 0x02,
-	0x12, 0x0f, 0x0a, 0x0b, 0x49, 0x4e, 0x54, 0x45, 0x47, 0x52, 0x41, 0x54, 0x49, 0x4f, 0x4e, 0x10,
-	0x03, 0x12, 0x0e, 0x0a, 0x0a, 0x50, 0x52, 0x4f, 0x4a, 0x45, 0x43, 0x54, 0x49, 0x4f, 0x4e, 0x10,
-	0x04, 0x42, 0x31, 0x5a, 0x2f, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f,
-	0x64, 0x6f, 0x67, 0x6d, 0x61, 0x74, 0x69, 0x71, 0x2f, 0x65, 0x6e, 0x67, 0x69, 0x6e, 0x65, 0x6b,
-	0x69, 0x74, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2f, 0x63, 0x6f, 0x6e, 0x66,
-	0x69, 0x67, 0x70, 0x62, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x6c, 0x65, 0x72, 0x73, 0x12, 0x45, 0x0a, 0x08, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73,
+	0x18, 0x04, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x29, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70,
+	0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x41, 0x70, 0x70, 0x6c, 0x69, 0x63, 0x61, 0x74,
+	0x69, 0x6f, 0x6e, 0x2e, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x45, 0x6e, 0x74, 0x72,
+	0x79, 0x52, 0x08, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x1a, 0x58, 0x0a, 0x0d, 0x4d,
+	0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x12, 0x10, 0x0a, 0x03,
+	0x6b, 0x65, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x03, 0x6b, 0x65, 0x79, 0x12, 0x31,
+	0x0a, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x1b, 0x2e,
+	0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x4d,
+	0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x4b, 0x69, 0x6e, 0x64, 0x52, 0x05, 0x76, 0x61, 0x6c, 0x75,
+	0x65, 0x3a, 0x02, 0x38, 0x01, 0x22, 0xc8, 0x02, 0x0a, 0x07, 0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65,
+	0x72, 0x12, 0x34, 0x0a, 0x08, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x18, 0x01, 0x20,
+	0x01, 0x28, 0x0b, 0x32, 0x18, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74,
+	0x6f, 0x62, 0x75, 0x66, 0x2e, 0x49, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x52, 0x08, 0x69,
+	0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x12, 0x17, 0x0a, 0x07, 0x67, 0x6f, 0x5f, 0x74, 0x79,
+	0x70, 0x65, 0x18, 0x02, 0x20, 0x01, 0x28, 0x09, 0x52, 0x06, 0x67, 0x6f, 0x54, 0x79, 0x70, 0x65,
+	0x12, 0x2f, 0x0a, 0x04, 0x74, 0x79, 0x70, 0x65, 0x18, 0x03, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x1b,
+	0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e,
+	0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x54, 0x79, 0x70, 0x65, 0x52, 0x04, 0x74, 0x79, 0x70,
+	0x65, 0x12, 0x41, 0x0a, 0x08, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x73, 0x18, 0x04, 0x20,
+	0x03, 0x28, 0x0b, 0x32, 0x25, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e, 0x70, 0x72, 0x6f, 0x74,
+	0x6f, 0x62, 0x75, 0x66, 0x2e, 0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x2e, 0x4d, 0x65, 0x73,
+	0x73, 0x61, 0x67, 0x65, 0x73, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x52, 0x08, 0x6d, 0x65, 0x73, 0x73,
+	0x61, 0x67, 0x65, 0x73, 0x12, 0x1f, 0x0a, 0x0b, 0x69, 0x73, 0x5f, 0x64, 0x69, 0x73, 0x61, 0x62,
+	0x6c, 0x65, 0x64, 0x18, 0x05, 0x20, 0x01, 0x28, 0x08, 0x52, 0x0a, 0x69, 0x73, 0x44, 0x69, 0x73,
+	0x61, 0x62, 0x6c, 0x65, 0x64, 0x1a, 0x59, 0x0a, 0x0d, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65,
+	0x73, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x12, 0x10, 0x0a, 0x03, 0x6b, 0x65, 0x79, 0x18, 0x01, 0x20,
+	0x01, 0x28, 0x09, 0x52, 0x03, 0x6b, 0x65, 0x79, 0x12, 0x32, 0x0a, 0x05, 0x76, 0x61, 0x6c, 0x75,
+	0x65, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x1c, 0x2e, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x2e,
+	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65,
+	0x55, 0x73, 0x61, 0x67, 0x65, 0x52, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x3a, 0x02, 0x38, 0x01,
+	0x22, 0x50, 0x0a, 0x0c, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x55, 0x73, 0x61, 0x67, 0x65,
+	0x12, 0x1f, 0x0a, 0x0b, 0x69, 0x73, 0x5f, 0x70, 0x72, 0x6f, 0x64, 0x75, 0x63, 0x65, 0x64, 0x18,
+	0x02, 0x20, 0x01, 0x28, 0x08, 0x52, 0x0a, 0x69, 0x73, 0x50, 0x72, 0x6f, 0x64, 0x75, 0x63, 0x65,
+	0x64, 0x12, 0x1f, 0x0a, 0x0b, 0x69, 0x73, 0x5f, 0x63, 0x6f, 0x6e, 0x73, 0x75, 0x6d, 0x65, 0x64,
+	0x18, 0x03, 0x20, 0x01, 0x28, 0x08, 0x52, 0x0a, 0x69, 0x73, 0x43, 0x6f, 0x6e, 0x73, 0x75, 0x6d,
+	0x65, 0x64, 0x2a, 0x4c, 0x0a, 0x0b, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x4b, 0x69, 0x6e,
+	0x64, 0x12, 0x18, 0x0a, 0x14, 0x55, 0x4e, 0x4b, 0x4e, 0x4f, 0x57, 0x4e, 0x5f, 0x4d, 0x45, 0x53,
+	0x53, 0x41, 0x47, 0x45, 0x5f, 0x4b, 0x49, 0x4e, 0x44, 0x10, 0x00, 0x12, 0x0b, 0x0a, 0x07, 0x43,
+	0x4f, 0x4d, 0x4d, 0x41, 0x4e, 0x44, 0x10, 0x01, 0x12, 0x09, 0x0a, 0x05, 0x45, 0x56, 0x45, 0x4e,
+	0x54, 0x10, 0x02, 0x12, 0x0b, 0x0a, 0x07, 0x54, 0x49, 0x4d, 0x45, 0x4f, 0x55, 0x54, 0x10, 0x03,
+	0x2a, 0x64, 0x0a, 0x0b, 0x48, 0x61, 0x6e, 0x64, 0x6c, 0x65, 0x72, 0x54, 0x79, 0x70, 0x65, 0x12,
+	0x18, 0x0a, 0x14, 0x55, 0x4e, 0x4b, 0x4e, 0x4f, 0x57, 0x4e, 0x5f, 0x48, 0x41, 0x4e, 0x44, 0x4c,
+	0x45, 0x52, 0x5f, 0x54, 0x59, 0x50, 0x45, 0x10, 0x00, 0x12, 0x0d, 0x0a, 0x09, 0x41, 0x47, 0x47,
+	0x52, 0x45, 0x47, 0x41, 0x54, 0x45, 0x10, 0x01, 0x12, 0x0b, 0x0a, 0x07, 0x50, 0x52, 0x4f, 0x43,
+	0x45, 0x53, 0x53, 0x10, 0x02, 0x12, 0x0f, 0x0a, 0x0b, 0x49, 0x4e, 0x54, 0x45, 0x47, 0x52, 0x41,
+	0x54, 0x49, 0x4f, 0x4e, 0x10, 0x03, 0x12, 0x0e, 0x0a, 0x0a, 0x50, 0x52, 0x4f, 0x4a, 0x45, 0x43,
+	0x54, 0x49, 0x4f, 0x4e, 0x10, 0x04, 0x42, 0x31, 0x5a, 0x2f, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62,
+	0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x64, 0x6f, 0x67, 0x6d, 0x61, 0x74, 0x69, 0x71, 0x2f, 0x65, 0x6e,
+	0x67, 0x69, 0x6e, 0x65, 0x6b, 0x69, 0x74, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66,
+	0x2f, 0x63, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x70, 0x62, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f,
+	0x33,
 }
 
 var (
@@ -388,25 +444,26 @@ func file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_rawDescGZ
 }
 
 var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_enumTypes = make([]protoimpl.EnumInfo, 2)
-var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_msgTypes = make([]protoimpl.MessageInfo, 4)
+var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_msgTypes = make([]protoimpl.MessageInfo, 5)
 var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_goTypes = []any{
 	(MessageKind)(0),            // 0: dogma.protobuf.MessageKind
 	(HandlerType)(0),            // 1: dogma.protobuf.HandlerType
 	(*Application)(nil),         // 2: dogma.protobuf.Application
 	(*Handler)(nil),             // 3: dogma.protobuf.Handler
-	nil,                         // 4: dogma.protobuf.Handler.ProducedMessagesEntry
-	nil,                         // 5: dogma.protobuf.Handler.ConsumedMessagesEntry
-	(*identitypb.Identity)(nil), // 6: dogma.protobuf.Identity
+	(*MessageUsage)(nil),        // 4: dogma.protobuf.MessageUsage
+	nil,                         // 5: dogma.protobuf.Application.MessagesEntry
+	nil,                         // 6: dogma.protobuf.Handler.MessagesEntry
+	(*identitypb.Identity)(nil), // 7: dogma.protobuf.Identity
 }
 var file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_depIdxs = []int32{
-	6, // 0: dogma.protobuf.Application.identity:type_name -> dogma.protobuf.Identity
+	7, // 0: dogma.protobuf.Application.identity:type_name -> dogma.protobuf.Identity
 	3, // 1: dogma.protobuf.Application.handlers:type_name -> dogma.protobuf.Handler
-	6, // 2: dogma.protobuf.Handler.identity:type_name -> dogma.protobuf.Identity
-	1, // 3: dogma.protobuf.Handler.type:type_name -> dogma.protobuf.HandlerType
-	4, // 4: dogma.protobuf.Handler.produced_messages:type_name -> dogma.protobuf.Handler.ProducedMessagesEntry
-	5, // 5: dogma.protobuf.Handler.consumed_messages:type_name -> dogma.protobuf.Handler.ConsumedMessagesEntry
-	0, // 6: dogma.protobuf.Handler.ProducedMessagesEntry.value:type_name -> dogma.protobuf.MessageKind
-	0, // 7: dogma.protobuf.Handler.ConsumedMessagesEntry.value:type_name -> dogma.protobuf.MessageKind
+	5, // 2: dogma.protobuf.Application.messages:type_name -> dogma.protobuf.Application.MessagesEntry
+	7, // 3: dogma.protobuf.Handler.identity:type_name -> dogma.protobuf.Identity
+	1, // 4: dogma.protobuf.Handler.type:type_name -> dogma.protobuf.HandlerType
+	6, // 5: dogma.protobuf.Handler.messages:type_name -> dogma.protobuf.Handler.MessagesEntry
+	0, // 6: dogma.protobuf.Application.MessagesEntry.value:type_name -> dogma.protobuf.MessageKind
+	4, // 7: dogma.protobuf.Handler.MessagesEntry.value:type_name -> dogma.protobuf.MessageUsage
 	8, // [8:8] is the sub-list for method output_type
 	8, // [8:8] is the sub-list for method input_type
 	8, // [8:8] is the sub-list for extension type_name
@@ -444,6 +501,18 @@ func file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_init() {
 				return nil
 			}
 		}
+		file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_msgTypes[2].Exporter = func(v any, i int) any {
+			switch v := v.(*MessageUsage); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
 	}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
@@ -451,7 +520,7 @@ func file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_github_com_dogmatiq_enginekit_protobuf_configpb_config_proto_rawDesc,
 			NumEnums:      2,
-			NumMessages:   4,
+			NumMessages:   5,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/protobuf/configpb/config.proto b/protobuf/configpb/config.proto
index c0cfd44..a78e12c 100644
--- a/protobuf/configpb/config.proto
+++ b/protobuf/configpb/config.proto
@@ -36,6 +36,10 @@ message Application {
 
   // Handlers is the set of handlers within the application.
   repeated Handler handlers = 3;
+
+  // MessageKinds is a map of each message type's fully-qualified Go type to its
+  // the kind of message it implemented by that type.
+  map<string, MessageKind> messages = 4;
 }
 
 // Handler is a message handler within an application.
@@ -50,18 +54,19 @@ message Handler {
   // Type is the handler's type.
   HandlerType type = 3;
 
-  // ProducedMessages is the set of messages produced by this handler.
-  //
-  // The keys are the fully-qualified names of the message's Go type and the
-  // value is the kind of message implemented by that type.
-  map<string, MessageKind> produced_messages = 4;
-
-  // ConsumedMessages is the set of messages consumed by this handler.
+  // messages is the set of messages produced and consumed by this handler.
   //
-  // The keys are the fully-qualified names of the message's Go type and the
-  // value is the kind of message implemented by that type.
-  map<string, MessageKind> consumed_messages = 5;
+  // The keys are the fully-qualified names of the message's Go type.
+  map<string, MessageUsage> messages = 4;
 
   // IsDisabled indicates whether the handler is disabled.
-  bool is_disabled = 6;
+  bool is_disabled = 5;
+}
+
+message MessageUsage {
+  // IsProduced indicates whether the message is produced by the handler.
+  bool is_produced = 2;
+
+  // IsConsumed indicates whether the message is consumed by the handler.
+  bool is_consumed = 3;
 }
diff --git a/protobuf/configpb/config_primo.pb.go b/protobuf/configpb/config_primo.pb.go
index 2af733e..b199e6f 100644
--- a/protobuf/configpb/config_primo.pb.go
+++ b/protobuf/configpb/config_primo.pb.go
@@ -29,6 +29,7 @@ func (b *ApplicationBuilder) From(x *Application) *ApplicationBuilder {
 	b.prototype.Identity = x.Identity
 	b.prototype.GoType = x.GoType
 	b.prototype.Handlers = x.Handlers
+	b.prototype.Messages = x.Messages
 	return b
 }
 
@@ -41,6 +42,7 @@ func (b *ApplicationBuilder) Build() *Application {
 		Identity: b.prototype.Identity,
 		GoType:   b.prototype.GoType,
 		Handlers: b.prototype.Handlers,
+		Messages: b.prototype.Messages,
 	}
 }
 
@@ -65,6 +67,13 @@ func (b *ApplicationBuilder) WithHandlers(v []*Handler) *ApplicationBuilder {
 	return b
 }
 
+// WithMessages configures the builder to set the Messages field to v,
+// then returns b.
+func (b *ApplicationBuilder) WithMessages(v map[string]MessageKind) *ApplicationBuilder {
+	b.prototype.Messages = v
+	return b
+}
+
 type HandlerBuilder struct {
 	prototype Handler
 }
@@ -83,8 +92,7 @@ func (b *HandlerBuilder) From(x *Handler) *HandlerBuilder {
 	b.prototype.Identity = x.Identity
 	b.prototype.GoType = x.GoType
 	b.prototype.Type = x.Type
-	b.prototype.ProducedMessages = x.ProducedMessages
-	b.prototype.ConsumedMessages = x.ConsumedMessages
+	b.prototype.Messages = x.Messages
 	b.prototype.IsDisabled = x.IsDisabled
 	return b
 }
@@ -95,12 +103,11 @@ func (b *HandlerBuilder) From(x *Handler) *HandlerBuilder {
 // not modify previously constructed messages.
 func (b *HandlerBuilder) Build() *Handler {
 	return &Handler{
-		Identity:         b.prototype.Identity,
-		GoType:           b.prototype.GoType,
-		Type:             b.prototype.Type,
-		ProducedMessages: b.prototype.ProducedMessages,
-		ConsumedMessages: b.prototype.ConsumedMessages,
-		IsDisabled:       b.prototype.IsDisabled,
+		Identity:   b.prototype.Identity,
+		GoType:     b.prototype.GoType,
+		Type:       b.prototype.Type,
+		Messages:   b.prototype.Messages,
+		IsDisabled: b.prototype.IsDisabled,
 	}
 }
 
@@ -125,24 +132,62 @@ func (b *HandlerBuilder) WithType(v HandlerType) *HandlerBuilder {
 	return b
 }
 
-// WithProducedMessages configures the builder to set the ProducedMessages field to v,
+// WithMessages configures the builder to set the Messages field to v,
 // then returns b.
-func (b *HandlerBuilder) WithProducedMessages(v map[string]MessageKind) *HandlerBuilder {
-	b.prototype.ProducedMessages = v
+func (b *HandlerBuilder) WithMessages(v map[string]*MessageUsage) *HandlerBuilder {
+	b.prototype.Messages = v
 	return b
 }
 
-// WithConsumedMessages configures the builder to set the ConsumedMessages field to v,
+// WithIsDisabled configures the builder to set the IsDisabled field to v,
 // then returns b.
-func (b *HandlerBuilder) WithConsumedMessages(v map[string]MessageKind) *HandlerBuilder {
-	b.prototype.ConsumedMessages = v
+func (b *HandlerBuilder) WithIsDisabled(v bool) *HandlerBuilder {
+	b.prototype.IsDisabled = v
 	return b
 }
 
-// WithIsDisabled configures the builder to set the IsDisabled field to v,
+type MessageUsageBuilder struct {
+	prototype MessageUsage
+}
+
+// NewMessageUsageBuilder returns a builder that constructs [MessageUsage] messages.
+func NewMessageUsageBuilder() *MessageUsageBuilder {
+	return &MessageUsageBuilder{}
+}
+
+// From configures the builder to use x as the prototype for new messages,
 // then returns b.
-func (b *HandlerBuilder) WithIsDisabled(v bool) *HandlerBuilder {
-	b.prototype.IsDisabled = v
+//
+// It performs a shallow copy of x, such that any changes made via the builder
+// do not modify x. It does not make a copy of the field values themselves.
+func (b *MessageUsageBuilder) From(x *MessageUsage) *MessageUsageBuilder {
+	b.prototype.IsProduced = x.IsProduced
+	b.prototype.IsConsumed = x.IsConsumed
+	return b
+}
+
+// Build returns a new [MessageUsage] containing the values configured via the builder.
+//
+// Each call returns a new message, such that future changes to the builder do
+// not modify previously constructed messages.
+func (b *MessageUsageBuilder) Build() *MessageUsage {
+	return &MessageUsage{
+		IsProduced: b.prototype.IsProduced,
+		IsConsumed: b.prototype.IsConsumed,
+	}
+}
+
+// WithIsProduced configures the builder to set the IsProduced field to v,
+// then returns b.
+func (b *MessageUsageBuilder) WithIsProduced(v bool) *MessageUsageBuilder {
+	b.prototype.IsProduced = v
+	return b
+}
+
+// WithIsConsumed configures the builder to set the IsConsumed field to v,
+// then returns b.
+func (b *MessageUsageBuilder) WithIsConsumed(v bool) *MessageUsageBuilder {
+	b.prototype.IsConsumed = v
 	return b
 }
 
@@ -302,6 +347,11 @@ func (x *Application) SetHandlers(v []*Handler) {
 	x.Handlers = v
 }
 
+// SetMessages sets the x.Messages field to v, then returns x.
+func (x *Application) SetMessages(v map[string]MessageKind) {
+	x.Messages = v
+}
+
 // SetIdentity sets the x.Identity field to v, then returns x.
 func (x *Handler) SetIdentity(v *identitypb.Identity) {
 	x.Identity = v
@@ -317,17 +367,22 @@ func (x *Handler) SetType(v HandlerType) {
 	x.Type = v
 }
 
-// SetProducedMessages sets the x.ProducedMessages field to v, then returns x.
-func (x *Handler) SetProducedMessages(v map[string]MessageKind) {
-	x.ProducedMessages = v
-}
-
-// SetConsumedMessages sets the x.ConsumedMessages field to v, then returns x.
-func (x *Handler) SetConsumedMessages(v map[string]MessageKind) {
-	x.ConsumedMessages = v
+// SetMessages sets the x.Messages field to v, then returns x.
+func (x *Handler) SetMessages(v map[string]*MessageUsage) {
+	x.Messages = v
 }
 
 // SetIsDisabled sets the x.IsDisabled field to v, then returns x.
 func (x *Handler) SetIsDisabled(v bool) {
 	x.IsDisabled = v
 }
+
+// SetIsProduced sets the x.IsProduced field to v, then returns x.
+func (x *MessageUsage) SetIsProduced(v bool) {
+	x.IsProduced = v
+}
+
+// SetIsConsumed sets the x.IsConsumed field to v, then returns x.
+func (x *MessageUsage) SetIsConsumed(v bool) {
+	x.IsConsumed = v
+}