diff --git a/models/node.go b/models/node.go
index 7b136ef..00946e0 100644
--- a/models/node.go
+++ b/models/node.go
@@ -1,82 +1,30 @@
 package models
 
 import (
-	"encoding/json"
-	"fmt"
 	"strings"
 )
 
+var PropertyPrefixes = []string{"_type::", "_status::", "_prio::"}
+
 type Node struct {
-	ID        string `json:"id"`
-	Title     string `json:"title"`
-	Content   string `json:"content,omitempty"`
-	DueDate   string `json:"due_date,omitempty"`
-	CreatedAt string `json:"created_at"`
-	UpdatedAt string `json:"updated_at"`
-	tags      []string
-	relations map[string][]string
+	ID        string              `json:"id"`
+	Title     string              `json:"title"`
+	Content   string              `json:"content,omitempty"`
+	DueDate   string              `json:"due_date,omitempty"`
+	CreatedAt string              `json:"created_at"`
+	UpdatedAt string              `json:"updated_at"`
+	Tags      []string            `json:"tags,omitempty"`
+	Relations map[string][]string `json:"relations,omitempty"`
 }
 
 func NewNode() *Node {
 	return &Node{
-		relations: make(map[string][]string),
+		Relations: make(map[string][]string),
 	}
 }
 
-var PropertyPrefixes = []string{"_type::", "_status::", "_prio::"}
-
-func (n *Node) MarshalJSON() ([]byte, error) {
-	type Alias Node
-	return json.Marshal(&struct {
-		*Alias
-		Tags      []string            `json:"tags,omitempty"`
-		Relations map[string][]string `json:"relations,omitempty"`
-	}{
-		Alias:     (*Alias)(n),
-		Tags:      n.tags,
-		Relations: n.relations,
-	})
-}
-
-func (n *Node) UnmarshalJSON(data []byte) error {
-	type Alias Node
-	aux := &struct {
-		*Alias
-		Tags      []string            `json:"tags,omitempty"`
-		Relations map[string][]string `json:"relations,omitempty"`
-	}{
-		Alias: (*Alias)(n),
-	}
-	if err := json.Unmarshal(data, &aux); err != nil {
-		return err
-	}
-	n.tags = aux.Tags
-	if aux.Relations != nil {
-		n.relations = aux.Relations
-	} else {
-		n.relations = make(map[string][]string)
-	}
-	return nil
-}
-
-func (n *Node) Tags() []string {
-	res := make([]string, len(n.tags))
-	copy(res, n.tags)
-	return res
-}
-
-func (n *Node) Relations() map[string][]string {
-	res := make(map[string][]string)
-	for k, v := range n.relations {
-		cv := make([]string, len(v))
-		copy(cv, v)
-		res[k] = cv
-	}
-	return res
-}
-
 func (n *Node) HasTag(tag string) bool {
-	for _, t := range n.tags {
+	for _, t := range n.Tags {
 		if t == tag {
 			return true
 		}
@@ -88,41 +36,35 @@ func (n *Node) AddTag(tag string) {
 	if tag == "" {
 		return
 	}
-	// check if it's a property tag
 	for _, prefix := range PropertyPrefixes {
 		if strings.HasPrefix(tag, prefix) {
-			// remove existing tags with this prefix
 			var newTags []string
-			for _, t := range n.tags {
+			for _, t := range n.Tags {
 				if !strings.HasPrefix(t, prefix) {
 					newTags = append(newTags, t)
 				}
 			}
-			n.tags = newTags
+			n.Tags = newTags
 			break
 		}
 	}
 	if !n.HasTag(tag) {
-		n.tags = append(n.tags, tag)
+		n.Tags = append(n.Tags, tag)
 	}
 }
 
-func (n *Node) RemoveTag(tag string) error {
-	if strings.HasPrefix(tag, "_type::") {
-		return fmt.Errorf("cannot remove _type tag")
-	}
+func (n *Node) RemoveTag(tag string) {
 	var newTags []string
-	for _, t := range n.tags {
+	for _, t := range n.Tags {
 		if t != tag {
 			newTags = append(newTags, t)
 		}
 	}
-	n.tags = newTags
-	return nil
+	n.Tags = newTags
 }
 
 func (n *Node) HasRelation(relType RelType, target string) bool {
-	for _, tgt := range n.relations[string(relType)] {
+	for _, tgt := range n.Relations[string(relType)] {
 		if tgt == target {
 			return true
 		}
@@ -131,41 +73,37 @@ func (n *Node) HasRelation(relType RelType, target string) bool {
 }
 
 func (n *Node) AddRelation(relType RelType, target string) {
-	if n.relations == nil {
-		n.relations = make(map[string][]string)
+	if n.Relations == nil {
+		n.Relations = make(map[string][]string)
 	}
 	if relType == RelAssignee || relType == RelCreated || relType == RelInNamespace {
-		n.relations[string(relType)] = []string{target}
+		n.Relations[string(relType)] = []string{target}
 		return
 	}
 	if !n.HasRelation(relType, target) {
-		n.relations[string(relType)] = append(n.relations[string(relType)], target)
+		n.Relations[string(relType)] = append(n.Relations[string(relType)], target)
 	}
 }
 
-func (n *Node) RemoveRelation(relType RelType, target string) error {
-	if relType == RelCreated {
-		return fmt.Errorf("cannot remove created relation")
-	}
-	if n.relations == nil {
-		return nil
+func (n *Node) RemoveRelation(relType RelType, target string) {
+	if n.Relations == nil {
+		return
 	}
 	var newTgts []string
-	for _, tgt := range n.relations[string(relType)] {
+	for _, tgt := range n.Relations[string(relType)] {
 		if tgt != target {
 			newTgts = append(newTgts, tgt)
 		}
 	}
 	if len(newTgts) == 0 {
-		delete(n.relations, string(relType))
+		delete(n.Relations, string(relType))
 	} else {
-		n.relations[string(relType)] = newTgts
+		n.Relations[string(relType)] = newTgts
 	}
-	return nil
 }
 
 func (n *Node) GetProperty(k string) string {
-	for _, t := range n.tags {
+	for _, t := range n.Tags {
 		if strings.HasPrefix(t, "_") {
 			if p := strings.SplitN(t[1:], "::", 2); len(p) == 2 && p[0] == k {
 				return p[1]
@@ -177,7 +115,7 @@ func (n *Node) GetProperty(k string) string {
 
 func (n *Node) GetDisplayTags() []string {
 	var tags []string
-	for _, t := range n.tags {
+	for _, t := range n.Tags {
 		if !strings.HasPrefix(t, "_") {
 			tags = append(tags, t)
 		}
diff --git a/output/output.go b/output/output.go
index b252746..3f2a269 100644
--- a/output/output.go
+++ b/output/output.go
@@ -77,7 +77,7 @@ func PrintNodes(w io.Writer, svc service.NodeService, nodes []*models.Node, json
 	})
 
 	for _, n := range nodes {
-		n_rels := n.Relations()
+		n_rels := n.Relations
 		ns_rel_node_ids := n_rels[string(models.RelInNamespace)]
 		ns_rel_node_titles := make([]string, 0, len(ns_rel_node_ids))
 		for _, id := range ns_rel_node_ids {
@@ -125,7 +125,7 @@ func PrintNode(w io.Writer, svc service.NodeService, n *models.Node, jsonOut boo
 		fmt.Fprintf(w, "\n  tags: %s\n", cPrimary.Sprint(strings.Join(tags, " • ")))
 	}
 
-	n_rels := n.Relations()
+	n_rels := n.Relations
 	for relType := range n_rels {
 		rel_node_ids := n_rels[string(relType)]
 		if len(rel_node_ids) > 0 {
diff --git a/service/node_service_impl.go b/service/node_service_impl.go
index bf337f0..9fd70ef 100644
--- a/service/node_service_impl.go
+++ b/service/node_service_impl.go
@@ -70,7 +70,7 @@ func (s *nodeServiceImpl) getAccessContext() (*accessContext, error) {
 	if err != nil {
 		return nil, err
 	}
-	rels := userNode.Relations()
+	rels := userNode.Relations
 	for _, nsID := range rels[string(models.RelHasWriteAccess)] {
 		ctx.writable[nsID] = true
 		ctx.readable[nsID] = true
@@ -83,7 +83,7 @@ func (s *nodeServiceImpl) getAccessContext() (*accessContext, error) {
 
 // nodeNamespaceID returns the first in_namespace target of n, or "" if none.
 func (s *nodeServiceImpl) nodeNamespaceID(n *models.Node) string {
-	ids := n.Relations()[string(models.RelInNamespace)]
+	ids := n.Relations[string(models.RelInNamespace)]
 	if len(ids) == 0 {
 		return ""
 	}
@@ -375,18 +375,17 @@ func (s *nodeServiceImpl) Update(id string, input UpdateInput) (*models.Node, er
 		// Compute new tag set using the model's AddTag/RemoveTag to preserve
 		// property-prefix replacement semantics.
 		tmp := models.NewNode()
-		for _, t := range current.Tags() {
+		for _, t := range current.Tags {
 			tmp.AddTag(t)
 		}
 		for _, t := range input.AddTags {
 			tmp.AddTag(t)
 		}
 		for _, t := range input.RemoveTags {
-			tmp.RemoveTag(t) //nolint: the error is only for _type:: removal, which is intentionally prevented
+			tmp.RemoveTag(t)
 		}
 
-		// Sync tags to store.
-		currentTags, newTags := current.Tags(), tmp.Tags()
+		currentTags, newTags := current.Tags, tmp.Tags
 		for _, t := range currentTags {
 			if !slices.Contains(newTags, t) {
 				if err := st.RemoveTag(id, t); err != nil {
@@ -409,7 +408,7 @@ func (s *nodeServiceImpl) Update(id string, input UpdateInput) (*models.Node, er
 			}
 		}
 
-		currentRels := current.Relations()
+		currentRels := current.Relations
 		for _, ri := range input.AddRels {
 			resolved, err := s.resolveRelTarget(st, ri)
 			if err != nil {
@@ -502,7 +501,7 @@ func (s *nodeServiceImpl) checkBlockers(id string) error {
 
 func (s *nodeServiceImpl) syncMentions(st store.Store, id string, current *models.Node, newTitle, newContent string) error {
 	existingMentionIDs := make(map[string]bool)
-	for _, uid := range current.Relations()[string(models.RelMentions)] {
+	for _, uid := range current.Relations[string(models.RelMentions)] {
 		existingMentionIDs[uid] = true
 	}
 	mentionedUserIDs := make(map[string]bool)