fix: AI connection type propagation and get_node improvements (v2.28.1) (#461)

* fix: AI connection type propagation and get_node improvements (v2.28.1)

Bug fixes:
- Issue #458: addConnection now preserves AI connection types (ai_tool, ai_memory, ai_languageModel) instead of defaulting to 'main'
- Fixed false positive "AI Agent has no tools connected" validation warning

Enhancements:
- Added expectedFormat field to resourceLocator properties in get_node output
- Added versionNotice field to make typeVersion more prominent

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* test: add missing test coverage for PR #461 improvements

- Added test for AI Agent validation positive case (tools properly connected)
- Added 3 tests for expectedFormat on resourceLocator properties

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/mcp/server.ts

@@ -2203,14 +2203,19 @@ Full documentation is being prepared. For now, use get_node_essentials for confi
     // Get operations (already parsed by repository)
     const operations = node.operations || [];
     
+    // Get the latest version - this is important for AI to use correct typeVersion
+    const latestVersion = node.version ?? '1';
+
     const result = {
       nodeType: node.nodeType,
       workflowNodeType: getWorkflowNodeType(node.package ?? 'n8n-nodes-base', node.nodeType),
       displayName: node.displayName,
       description: node.description,
       category: node.category,
-      version: node.version ?? '1',
+      version: latestVersion,
       isVersioned: node.isVersioned ?? false,
+      // Prominent warning to use the correct typeVersion
+      versionNotice: `⚠️ Use typeVersion: ${latestVersion} when creating this node`,
       requiredProperties: essentials.required,
       commonProperties: essentials.common,
       operations: operations.map((op: any) => ({

src/services/property-filter.ts

@@ -16,6 +16,11 @@ export interface SimplifiedProperty {
   placeholder?: string;
   showWhen?: Record<string, any>;
   usageHint?: string;
+  expectedFormat?: {
+    structure: Record<string, string>;
+    modes?: string[];
+    example: Record<string, any>;
+  };
 }
 
 export interface EssentialConfig {
@@ -322,7 +327,18 @@ export class PropertyFilter {
         };
       });
     }
-    
+
+    // Add expectedFormat for resourceLocator types - critical for correct configuration
+    if (prop.type === 'resourceLocator') {
+      const modes = prop.modes?.map((m: any) => m.name || m) || ['list', 'id'];
+      const defaultValue = prop.default?.value || 'your-resource-id';
+      simplified.expectedFormat = {
+        structure: { mode: 'string', value: 'string' },
+        modes,
+        example: { mode: 'id', value: defaultValue }
+      };
+    }
+
     // Include simple display conditions (max 2 conditions)
     if (prop.displayOptions?.show) {
       const conditions = Object.keys(prop.displayOptions.show);

src/services/workflow-diff-engine.ts

@@ -757,7 +757,8 @@ export class WorkflowDiffEngine {
     const { sourceOutput, sourceIndex } = this.resolveSmartParameters(workflow, operation);
 
     // Use nullish coalescing to properly handle explicit 0 values
-    const targetInput = operation.targetInput ?? 'main';
+    // Default targetInput to sourceOutput to preserve connection type for AI connections (ai_tool, ai_memory, etc.)
+    const targetInput = operation.targetInput ?? sourceOutput;
     const targetIndex = operation.targetIndex ?? 0;
 
     // Initialize source node connections object

src/services/workflow-validator.ts

@@ -1137,16 +1137,23 @@ export class WorkflowValidator {
     }
 
     // Check for AI Agent workflows
-    const aiAgentNodes = workflow.nodes.filter(n => 
-      n.type.toLowerCase().includes('agent') || 
+    const aiAgentNodes = workflow.nodes.filter(n =>
+      n.type.toLowerCase().includes('agent') ||
       n.type.includes('langchain.agent')
     );
-    
+
     if (aiAgentNodes.length > 0) {
       // Check if AI agents have tools connected
+      // Tools connect TO the agent, so we need to find connections where the target is the agent
       for (const agentNode of aiAgentNodes) {
-        const connections = workflow.connections[agentNode.name];
-        if (!connections?.ai_tool || connections.ai_tool.flat().filter(c => c).length === 0) {
+        // Search all connections to find ones targeting this agent via ai_tool
+        const hasToolConnected = Object.values(workflow.connections).some(sourceOutputs => {
+          const aiToolConnections = sourceOutputs.ai_tool;
+          if (!aiToolConnections) return false;
+          return aiToolConnections.flat().some(conn => conn && conn.node === agentNode.name);
+        });
+
+        if (!hasToolConnected) {
           result.warnings.push({
             type: 'warning',
             nodeId: agentNode.id,