diff --git a/data/document.go b/data/document.go
new file mode 100644
index 00000000..1fb26417
--- /dev/null
+++ b/data/document.go
@@ -0,0 +1,58 @@
+package data
+
+import (
+	"github.com/anytypeio/go-anytype-infrastructure-experiments/data/pb"
+	"github.com/anytypeio/go-anytype-infrastructure-experiments/data/threadmodels"
+)
+
+type AccountData struct {
+	Identity string
+	EncKey   threadmodels.EncryptionPrivKey
+}
+
+type Document struct {
+	thread          threadmodels.Thread
+	stateProvider   InitialStateProvider
+	accountData     AccountData
+	decoder         threadmodels.SigningPubKeyDecoder
+	aclTree         *Tree
+	fullTree        *Tree
+	aclTreeBuilder  *ACLTreeBuilder
+	aclStateBuilder *ACLStateBuilder
+}
+
+type UpdateResult int
+
+const (
+	UpdateResultAppend = iota
+	UpdateResultRebuild
+	UpdateResultExists
+	UpdateResultNoAction
+)
+
+func NewDocument(
+	thread threadmodels.Thread,
+	stateProvider InitialStateProvider,
+	accountData AccountData) *Document {
+	return &Document{
+		thread:        thread,
+		stateProvider: stateProvider,
+		accountData:   accountData,
+		decoder:       threadmodels.NewEd25519Decoder(),
+	}
+}
+
+func (d *Document) Update(changes []*pb.ACLChange) (DocumentState, UpdateResult, error) {
+	return nil, 0, nil
+}
+
+func (d *Document) Build() (DocumentState, error) {
+	treeBuilder := NewTreeBuilder(d.thread, threadmodels.NewEd25519Decoder())
+
+	return treeBuilder.Build(fromStart)
+	return nil, nil
+}
+
+func (d *Document) State() DocumentState {
+	return nil
+}
diff --git a/data/documentcontext.go b/data/documentcontext.go
new file mode 100644
index 00000000..eb4ff5cd
--- /dev/null
+++ b/data/documentcontext.go
@@ -0,0 +1,32 @@
+package data
+
+import "github.com/anytypeio/go-anytype-infrastructure-experiments/data/threadmodels"
+
+type documentContext struct {
+	aclTree       *Tree
+	fullTree      *Tree
+	identity      string
+	encryptionKey threadmodels.EncryptionPrivKey
+	decoder       threadmodels.SigningPubKeyDecoder
+	aclState      *ACLState
+	docState      DocumentState
+	changeCache   map[string]*Change
+	identityKeys  map[string]threadmodels.SigningPubKey
+}
+
+func newDocumentContext(
+	identity string,
+	encryptionKey threadmodels.EncryptionPrivKey,
+	decoder threadmodels.SigningPubKeyDecoder) *documentContext {
+	return &documentContext{
+		aclTree:       &Tree{},
+		fullTree:      &Tree{},
+		identity:      identity,
+		encryptionKey: encryptionKey,
+		decoder:       decoder,
+		aclState:      nil,
+		docState:      nil,
+		changeCache:   make(map[string]*Change),
+		identityKeys:  make(map[string]threadmodels.SigningPubKey),
+	}
+}
diff --git a/data/pb/protos/plaintextchanges.proto b/data/pb/protos/plaintextchanges.proto
index 4b5e9d37..0f9177af 100644
--- a/data/pb/protos/plaintextchanges.proto
+++ b/data/pb/protos/plaintextchanges.proto
@@ -2,6 +2,8 @@ syntax = "proto3";
 package anytype;
 option go_package = "pb";
 
+// TODO: move to separate package
+
 message PlainTextChange {
   message Content {
     oneof value {
diff --git a/data/threadmodels/models.go b/data/threadmodels/models.go
index aa388596..63367f28 100644
--- a/data/threadmodels/models.go
+++ b/data/threadmodels/models.go
@@ -8,8 +8,9 @@ import (
 type Thread interface {
 	ID() string
 	Heads() []string
-	// TODO: add ACL heads
 	GetChange(ctx context.Context, recordID string) (*RawChange, error)
+	//SetHeads(heads []string)
+	//AddChanges(*pb.ACLChange)
 	PushChange(payload proto.Marshaler) (id string, err error)
 }