diff --git a/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-details/signals-details.component.ts b/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-details/signals-details.component.ts
index 9d6975f3fe9..e46d7430025 100644
--- a/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-details/signals-details.component.ts
+++ b/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-details/signals-details.component.ts
@@ -19,13 +19,14 @@ import {
 } from './signals-value-tree/signals-value-tree.component';
 import {ButtonComponent} from '../../../../shared/button/button.component';
 
-const TYPE_CLASS_MAP: {[key: string]: string} = {
+const TYPE_CLASS_MAP: {[key in DebugSignalGraphNode['kind']]: string} = {
   'signal': 'type-signal',
   'computed': 'type-computed',
   'effect': 'type-effect',
   'afterRenderEffectPhase': 'type-effect',
   'template': 'type-template',
   'linkedSignal': 'type-linked-signal',
+  'unknown': 'type-unknown',
 };
 
 @Component({
diff --git a/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-visualizer.ts b/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-visualizer.ts
index 6024db331b4..66d7508e24c 100644
--- a/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-visualizer.ts
+++ b/devtools/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/signals-view/signals-visualizer.ts
@@ -10,13 +10,14 @@ import {DebugSignalGraph, DebugSignalGraphNode} from '../../../../../../protocol
 import * as d3 from 'd3';
 import {graphlib, render as dagreRender} from 'dagre-d3-es';
 
-const KIND_CLASS_MAP: {[key: string]: string} = {
+const KIND_CLASS_MAP: {[key in DebugSignalGraphNode['kind']]: string} = {
   'signal': 'kind-signal',
   'computed': 'kind-computed',
   'effect': 'kind-effect',
   'afterRenderEffectPhase': 'kind-effect',
   'template': 'kind-template',
   'linkedSignal': 'kind-linked-signal',
+  'unknown': 'kind-unknown',
 };
 
 export class SignalsGraphVisualizer {
diff --git a/devtools/projects/protocol/src/lib/messages.ts b/devtools/projects/protocol/src/lib/messages.ts
index d9938272d69..bc2973f80f2 100644
--- a/devtools/projects/protocol/src/lib/messages.ts
+++ b/devtools/projects/protocol/src/lib/messages.ts
@@ -18,7 +18,14 @@ import {
 
 export interface DebugSignalGraphNode {
   id: string;
-  kind: string;
+  kind:
+    | 'signal'
+    | 'computed'
+    | 'effect'
+    | 'template'
+    | 'linkedSignal'
+    | 'afterRenderEffectPhase'
+    | 'unknown';
   epoch: number;
   label?: string;
   preview: Descriptor;