fix: persist Pascal agent scene after live updates

services/pascal-editor/apps/editor/lib/pascal-agent-mcp.ts

@@ -95,12 +95,6 @@ function readSceneName(result: unknown, fallback: string): string {
     : fallback
 }
 
-function readSceneVersion(result: unknown): number | null {
-  const version = (result as { structuredContent?: { version?: unknown } })?.structuredContent
-    ?.version
-  return typeof version === 'number' && Number.isInteger(version) && version > 0 ? version : null
-}
-
 function assertToolSucceeded(result: unknown, operation: string): void {
   if ((result as { isError?: unknown })?.isError === true) {
     throw new Error(`Pascal MCP ${operation} failed.`)
@@ -138,7 +132,6 @@ export async function createPascalAgentMcpSession(params: {
     )
     assertToolSucceeded(loadResult, 'load_scene')
     const sceneName = readSceneName(loadResult, params.sceneId)
-    let currentVersion = readSceneVersion(loadResult)
     const saveScene = withStepTimeout(requireTool(allTools, 'save_scene'), params.stepTimeoutMs)
 
     const scopedSaveScene: RequiredTool = {
@@ -148,7 +141,7 @@ export async function createPascalAgentMcpSession(params: {
         const result = await saveScene.execute(
           {
             ...candidate,
-            expectedVersion: currentVersion ?? undefined,
+            expectedVersion: undefined,
             graph: undefined,
             id: params.sceneId,
             includeCurrentScene: true,
@@ -157,8 +150,6 @@ export async function createPascalAgentMcpSession(params: {
           },
           options,
         )
-        const savedVersion = readSceneVersion(result)
-        if (savedVersion) currentVersion = savedVersion
         return result
       },
     }

services/pascal-editor/packages/mcp/src/tools/scene-lifecycle/save-scene.test.ts

@@ -167,4 +167,25 @@ describe('save_scene', () => {
     })
     expect(result.isError).toBe(true)
   })
+
+  test('uses the active scene version when the caller omits expectedVersion', async () => {
+    const first = await client.callTool({
+      name: 'save_scene',
+      arguments: { id: 'active-scene', name: 'First' },
+    })
+    expect(first.isError).toBeFalsy()
+
+    const second = await client.callTool({
+      name: 'save_scene',
+      arguments: { id: 'active-scene', name: 'Second', expectedVersion: 1 },
+    })
+    expect(second.isError).toBeFalsy()
+
+    const final = await client.callTool({
+      name: 'save_scene',
+      arguments: { id: 'active-scene', name: 'Final' },
+    })
+    expect(final.isError).toBeFalsy()
+    expect(parseToolText(final.content as StoredTextContent[]).version).toBe(3)
+  })
 })

services/pascal-editor/packages/mcp/src/tools/scene-lifecycle/save-scene.ts

@@ -118,6 +118,10 @@ export function registerSaveScene(server: McpServer, bridge: SceneOperations): v
         sceneGraph = graph as unknown as SceneGraph
       }
 
+      const activeScene = includeCurrentScene ? bridge.getActiveScene() : null
+      const resolvedExpectedVersion =
+        expectedVersion ?? (activeScene && activeScene.id === id ? activeScene.version : undefined)
+
       try {
         const meta = await bridge.saveScene({
           ...(id !== undefined ? { id } : {}),
@@ -125,7 +129,9 @@ export function registerSaveScene(server: McpServer, bridge: SceneOperations): v
           ...(projectId !== undefined ? { projectId } : {}),
           graph: sceneGraph,
           ...(thumbnail !== undefined ? { thumbnailUrl: thumbnail } : {}),
-          ...(expectedVersion !== undefined ? { expectedVersion } : {}),
+          ...(resolvedExpectedVersion !== undefined
+            ? { expectedVersion: resolvedExpectedVersion }
+            : {}),
           saveMode,
           ...(publish !== undefined ? { publish } : {}),
           operation: 'save_scene',
@@ -145,7 +151,7 @@ export function registerSaveScene(server: McpServer, bridge: SceneOperations): v
       } catch (err) {
         if (err instanceof SceneVersionConflictError) {
           throwMcpError(ErrorCode.InvalidRequest, 'version_conflict', {
-            expectedVersion,
+            expectedVersion: resolvedExpectedVersion,
             id,
           })
         }