Resolve GitHub Issue 292 in n8n-mcp (#375)

* docs: add comprehensive documentation for removing node properties with undefined

Add detailed documentation section for property removal pattern in n8n_update_partial_workflow tool:
- New "Removing Properties with undefined" section explaining the pattern
- Examples showing basic, nested, and batch property removal
- Migration guide for deprecated properties (continueOnFail → onError)
- Best practices for when to use undefined
- Pitfalls to avoid (null vs undefined, mutual exclusivity, etc.)

This addresses the documentation gap reported in issue #292 where users
were confused about how to remove properties during node updates.

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>

* fix: correct array property removal documentation in n8n_update_partial_workflow (Issue #292)

Fixed critical documentation error showing array index notation [0] which doesn't work.
The setNestedProperty implementation treats "headers[0]" as a literal object key, not an array index.

Changes:
- Updated nested property removal section to show entire array removal
- Corrected example rm5 to use "parameters.headers" instead of "parameters.headers[0]"
- Replaced misleading pitfall with accurate warning about array index notation not being supported

Impact:
- Prevents user confusion and non-functional code
- All examples now show correct, working patterns
- Clear warning helps users avoid this mistake

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>

CHANGELOG.md

@@ -7,6 +7,95 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.22.7] - 2025-10-26
+
+### 📝 Documentation Fixes
+
+**Issue #292: Corrected Array Property Removal Documentation in n8n_update_partial_workflow**
+
+Fixed critical documentation error in property removal patterns that could have led users to write non-functional code.
+
+#### Problem
+
+The documentation incorrectly showed using array index notation `[0]` for removing array elements:
+```javascript
+// INCORRECT (doesn't work as shown)
+updates: { "parameters.headers[0]": undefined }
+```
+
+**Root Cause**: The `setNestedProperty` implementation doesn't parse array index notation like `[0]`. It treats `headers[0]` as a literal object key, not an array index.
+
+**Impact**: Users following the documentation would write code that doesn't behave as expected. The property `headers[0]` would be treated as an object key, not an array element reference.
+
+#### Fixed
+
+**Three documentation corrections in `src/mcp/tool-docs/workflow_management/n8n-update-partial-workflow.ts`:**
+
+1. **Nested Property Removal Section** (lines 236-244):
+   - Changed comment from `// Remove array element` to `// Remove entire array property`
+   - Changed code from `"parameters.headers[0]": undefined` to `"parameters.headers": undefined`
+
+2. **Example rm5** (line 340):
+   - Changed comment from `// Remove array element` to `// Remove entire array property`
+   - Changed code from `"parameters.headers[0]": undefined` to `"parameters.headers": undefined`
+
+3. **Pitfalls Section** (line 405):
+   - OLD: `'Array element removal with undefined removes the element at that index, which may shift subsequent indices'`
+   - NEW: `'Array index notation (e.g., "parameters.headers[0]") is not supported - remove the entire array property instead'`
+
+#### Correct Usage
+
+**To remove an array property:**
+```javascript
+// Correct: Remove entire array
+n8n_update_partial_workflow({
+  id: "wf_012",
+  operations: [{
+    type: "updateNode",
+    nodeName: "HTTP Request",
+    updates: { "parameters.headers": undefined }  // Remove entire headers array
+  }]
+});
+```
+
+**NOT:**
+```javascript
+// Incorrect: Array index notation doesn't work
+updates: { "parameters.headers[0]": undefined }  // Treated as object key "headers[0]"
+```
+
+#### Impact
+
+- **Prevents User Confusion**: Clear documentation on what works vs. what doesn't
+- **Accurate Examples**: All examples now show correct, working patterns
+- **Better Error Prevention**: Pitfall warning helps users avoid this mistake
+- **No Code Changes**: This is purely a documentation fix - no implementation changes needed
+
+#### Testing
+
+- ✅ Documentation reviewed by code-reviewer agent
+- ✅ Tested by n8n-mcp-tester agent
+- ✅ All examples verified against actual implementation behavior
+- ✅ Pitfall accurately describes technical limitation
+
+#### Files Changed
+
+**Documentation (1 file)**:
+- `src/mcp/tool-docs/workflow_management/n8n-update-partial-workflow.ts` - Corrected 3 instances of array property removal documentation
+
+**Configuration (2 files)**:
+- `package.json` - Version bump to 2.22.7
+- `package.runtime.json` - Version bump to 2.22.7
+
+#### Related
+
+- **Issue**: #292 - Missing documentation on how to remove node properties using `updateNode`
+- **PR**: #375 - Resolve GitHub Issue 292 in n8n-mcp
+- **Code Review**: Identified critical array index notation documentation error
+- **Root Cause**: Implementation doesn't parse array bracket notation `[N]`
+
+Conceived by Romuald Członkowski - [www.aiadvisors.pl/en](https://www.aiadvisors.pl/en)
+
 ## [2.22.6] - 2025-10-25
 
 ### 🐛 Bug Fixes

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.22.6",
+  "version": "2.22.7",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

package.runtime.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp-runtime",
-  "version": "2.22.5",
+  "version": "2.22.7",
   "description": "n8n MCP Server Runtime Dependencies Only",
   "private": true,
   "dependencies": {

src/mcp/tool-docs/workflow_management/n8n-update-partial-workflow.ts

@@ -186,7 +186,115 @@ Please choose a different name.
 - Simply rename nodes with updateNode - no manual connection operations needed
 - Multiple renames in one call work atomically
 - Can rename a node and add/remove connections using the new name in the same batch
-- Use \`validateOnly: true\` to preview effects before applying`,
+- Use \`validateOnly: true\` to preview effects before applying
+
+## Removing Properties with undefined
+
+To remove a property from a node, set its value to \`undefined\` in the updates object. This is essential when migrating from deprecated properties or cleaning up optional configuration fields.
+
+### Why Use undefined?
+- **Property removal vs. null**: Setting a property to \`undefined\` removes it completely from the node object, while \`null\` sets the property to a null value
+- **Validation constraints**: Some properties are mutually exclusive (e.g., \`continueOnFail\` and \`onError\`). Simply setting one without removing the other will fail validation
+- **Deprecated property migration**: When n8n deprecates properties, you must remove the old property before the new one will work
+
+### Basic Property Removal
+\`\`\`javascript
+// Remove error handling configuration
+n8n_update_partial_workflow({
+  id: "wf_123",
+  operations: [{
+    type: "updateNode",
+    nodeName: "HTTP Request",
+    updates: { onError: undefined }
+  }]
+});
+
+// Remove disabled flag
+n8n_update_partial_workflow({
+  id: "wf_456",
+  operations: [{
+    type: "updateNode",
+    nodeId: "node_abc",
+    updates: { disabled: undefined }
+  }]
+});
+\`\`\`
+
+### Nested Property Removal
+Use dot notation to remove nested properties:
+\`\`\`javascript
+// Remove nested parameter
+n8n_update_partial_workflow({
+  id: "wf_789",
+  operations: [{
+    type: "updateNode",
+    nodeName: "API Request",
+    updates: { "parameters.authentication": undefined }
+  }]
+});
+
+// Remove entire array property
+n8n_update_partial_workflow({
+  id: "wf_012",
+  operations: [{
+    type: "updateNode",
+    nodeName: "HTTP Request",
+    updates: { "parameters.headers": undefined }
+  }]
+});
+\`\`\`
+
+### Migrating from Deprecated Properties
+Common scenario: replacing \`continueOnFail\` with \`onError\`:
+\`\`\`javascript
+// WRONG: Setting only the new property leaves the old one
+n8n_update_partial_workflow({
+  id: "wf_123",
+  operations: [{
+    type: "updateNode",
+    nodeName: "HTTP Request",
+    updates: { onError: "continueErrorOutput" }
+  }]
+});
+// Error: continueOnFail and onError are mutually exclusive
+
+// CORRECT: Remove the old property first
+n8n_update_partial_workflow({
+  id: "wf_123",
+  operations: [{
+    type: "updateNode",
+    nodeName: "HTTP Request",
+    updates: {
+      continueOnFail: undefined,
+      onError: "continueErrorOutput"
+    }
+  }]
+});
+\`\`\`
+
+### Batch Property Removal
+Remove multiple properties in one operation:
+\`\`\`javascript
+n8n_update_partial_workflow({
+  id: "wf_345",
+  operations: [{
+    type: "updateNode",
+    nodeName: "Data Processor",
+    updates: {
+      continueOnFail: undefined,
+      alwaysOutputData: undefined,
+      "parameters.legacy_option": undefined
+    }
+  }]
+});
+\`\`\`
+
+### When to Use undefined
+- Removing deprecated properties during migration
+- Cleaning up optional configuration flags
+- Resolving mutual exclusivity validation errors
+- Removing stale or unnecessary node metadata
+- Simplifying node configuration`,
     parameters: {
       id: { type: 'string', required: true, description: 'Workflow ID to update' },
       operations: {
@@ -223,7 +331,13 @@ Please choose a different name.
       '// Vector Store setup: Connect embeddings and documents\nn8n_update_partial_workflow({id: "ai7", operations: [\n  {type: "addConnection", source: "Embeddings OpenAI", target: "Pinecone Vector Store", sourceOutput: "ai_embedding"},\n  {type: "addConnection", source: "Default Data Loader", target: "Pinecone Vector Store", sourceOutput: "ai_document"}\n]})',
       '// Connect Vector Store Tool to AI Agent (retrieval setup)\nn8n_update_partial_workflow({id: "ai8", operations: [\n  {type: "addConnection", source: "Pinecone Vector Store", target: "Vector Store Tool", sourceOutput: "ai_vectorStore"},\n  {type: "addConnection", source: "Vector Store Tool", target: "AI Agent", sourceOutput: "ai_tool"}\n]})',
       '// Rewire AI Agent to use different language model\nn8n_update_partial_workflow({id: "ai9", operations: [{type: "rewireConnection", source: "AI Agent", from: "OpenAI Chat Model", to: "Anthropic Chat Model", sourceOutput: "ai_languageModel"}]})',
-      '// Replace all AI tools for an agent\nn8n_update_partial_workflow({id: "ai10", operations: [\n  {type: "removeConnection", source: "Old Tool 1", target: "AI Agent", sourceOutput: "ai_tool"},\n  {type: "removeConnection", source: "Old Tool 2", target: "AI Agent", sourceOutput: "ai_tool"},\n  {type: "addConnection", source: "New HTTP Tool", target: "AI Agent", sourceOutput: "ai_tool"},\n  {type: "addConnection", source: "New Code Tool", target: "AI Agent", sourceOutput: "ai_tool"}\n]})'
+      '// Replace all AI tools for an agent\nn8n_update_partial_workflow({id: "ai10", operations: [\n  {type: "removeConnection", source: "Old Tool 1", target: "AI Agent", sourceOutput: "ai_tool"},\n  {type: "removeConnection", source: "Old Tool 2", target: "AI Agent", sourceOutput: "ai_tool"},\n  {type: "addConnection", source: "New HTTP Tool", target: "AI Agent", sourceOutput: "ai_tool"},\n  {type: "addConnection", source: "New Code Tool", target: "AI Agent", sourceOutput: "ai_tool"}\n]})',
+      '\n// ============ REMOVING PROPERTIES EXAMPLES ============',
+      '// Remove a simple property\nn8n_update_partial_workflow({id: "rm1", operations: [{type: "updateNode", nodeName: "HTTP Request", updates: {onError: undefined}}]})',
+      '// Migrate from deprecated continueOnFail to onError\nn8n_update_partial_workflow({id: "rm2", operations: [{type: "updateNode", nodeName: "HTTP Request", updates: {continueOnFail: undefined, onError: "continueErrorOutput"}}]})',
+      '// Remove nested property\nn8n_update_partial_workflow({id: "rm3", operations: [{type: "updateNode", nodeName: "API Request", updates: {"parameters.authentication": undefined}}]})',
+      '// Remove multiple properties\nn8n_update_partial_workflow({id: "rm4", operations: [{type: "updateNode", nodeName: "Data Processor", updates: {continueOnFail: undefined, alwaysOutputData: undefined, "parameters.legacy_option": undefined}}]})',
+      '// Remove entire array property\nn8n_update_partial_workflow({id: "rm5", operations: [{type: "updateNode", nodeName: "HTTP Request", updates: {"parameters.headers": undefined}}]})'
     ],
     useCases: [
       'Rewire connections when replacing nodes',
@@ -259,7 +373,11 @@ Please choose a different name.
       'Connect language model BEFORE adding AI Agent to ensure validation passes',
       'Use targetIndex for fallback models (primary=0, fallback=1)',
       'Batch AI component connections in a single operation for atomicity',
-      'Validate AI workflows after connection changes to catch configuration errors'
+      'Validate AI workflows after connection changes to catch configuration errors',
+      'To remove properties, set them to undefined (not null) in the updates object',
+      'When migrating from deprecated properties, remove the old property and add the new one in the same operation',
+      'Use undefined to resolve mutual exclusivity validation errors between properties',
+      'Batch multiple property removals in a single updateNode operation for efficiency'
     ],
     pitfalls: [
       '**REQUIRES N8N_API_URL and N8N_API_KEY environment variables** - will not work without n8n API access',
@@ -279,7 +397,12 @@ Please choose a different name.
       '**Auto-sanitization behavior**: Binary operators (equals, contains) automatically have singleValue removed; unary operators (isEmpty, isNotEmpty) automatically get singleValue:true added',
       '**Auto-sanitization runs on ALL nodes**: When ANY update is made, ALL nodes in the workflow are sanitized (not just modified ones)',
       '**Auto-sanitization cannot fix everything**: It fixes operator structures and missing metadata, but cannot fix broken connections or branch mismatches',
-      '**Corrupted workflows beyond repair**: Workflows in paradoxical states (API returns corrupt, API rejects updates) cannot be fixed via API - must be recreated'
+      '**Corrupted workflows beyond repair**: Workflows in paradoxical states (API returns corrupt, API rejects updates) cannot be fixed via API - must be recreated',
+      'Setting a property to null does NOT remove it - use undefined instead',
+      'When properties are mutually exclusive (e.g., continueOnFail and onError), setting only the new property will fail - you must remove the old one with undefined',
+      'Removing a required property may cause validation errors - check node documentation first',
+      'Nested property removal with dot notation only removes the specific nested field, not the entire parent object',
+      'Array index notation (e.g., "parameters.headers[0]") is not supported - remove the entire array property instead'
     ],
     relatedTools: ['n8n_update_full_workflow', 'n8n_get_workflow', 'validate_workflow', 'tools_documentation']
   }