n8n-skills/docs/MCP_TESTING_LOG.md

MCP Tool Testing Log

Generated: 2025-10-20

Purpose: Document actual tool responses for skill content creation

This log contains real responses from n8n-mcp tools to inform accurate skill content.

---

n8n API Status

Health Check Result:

{
  "status": "ok",
  "apiUrl": "https://n8n-test.n8n-mcp.com",
  "mcpVersion": "2.20.3",
  "versionCheck": "up to date",
  "responseTime": 798ms
}

✅ n8n API Tools Available: All workflow creation/management tools functional

---

Database Statistics

{
  "totalNodes": 537,
  "totalTemplates": 2653,
  "statistics": {
    "aiTools": 270,
    "triggers": 108,
    "versionedNodes": 141,
    "nodesWithDocumentation": 470,
    "documentationCoverage": "88%"
  },
  "packageBreakdown": [
    {"package": "@n8n/n8n-nodes-langchain", "nodeCount": 100},
    {"package": "n8n-nodes-base", "nodeCount": 437}
  ]
}

Key Insights:

• 537 nodes total (437 base + 100 langchain)
• 270 AI-capable tools
• 108 trigger nodes
• 88% documentation coverage
• 2,653 templates with avg 4,115 views

---

Search Tool Testing

search_nodes - Common Queries

Query: "webhook" → Returns Webhook (trigger), Respond to Webhook (transform)

• nodeType format: nodes-base.webhook
• workflowNodeType format: n8n-nodes-base.webhook
• ⚠️ Critical: Use different formats for different tools!

Query: "http" → Returns HTTP Request, HTTP Request Tool (AI), Code Tool

• Regular: nodes-base.httpRequest
• AI Tool: nodes-langchain.toolHttpRequest

Query: "database" → Returns Firebase, Redis Vector Store, etc.

---

Node Essentials Testing

Webhook Node

Key Properties:

• httpMethod: GET, POST, PUT, DELETE, etc. (default: GET)
• path: Webhook URL path (e.g., "form-submit")
• responseMode: onReceived, lastNode, responseNode
• CRITICAL: Webhook data structure is $json.body.* not $json.*

Output Structure:

{
  "headers": {...},
  "params": {...},
  "query": {...},
  "body": {  // ⚠️ User data is HERE!
    "name": "John",
    "email": "john@example.com"
  }
}

---

Validation Testing

Validation Profiles Comparison

Test Config: {resource: "channel", operation: "create"} on Slack node

Result: Missing required field "name"

• All profiles detected this error
• Fix provided: "Provide a channel name"
• Warning about rate limits (best practice)

---

Template Analysis

Total Templates: 2,653 Popular Templates (webhook + slack):

• #2947: Weather via Slack (1,500 views) - Webhook → OpenStreetMap → NWS → Slack
• #4039: Download Slack Media (778 views) - SlackTrigger → HTTP Request
• #5529: Jamf Patch to Slack (147 views) - Complex multi-node

Key Pattern: Webhook → Transform → Action → Notify (5-7 nodes avg)

---

Critical Findings for Skills

1. Expression Syntax (Skill #1)

• ✅ Webhook data under .body (not root)
• ✅ Code nodes use direct access ($json), NOT expressions ({{}})
• ✅ Node references: $node["Node Name"].json.field

2. MCP Tools Expert (Skill #2)

• ✅ nodeType formats differ: nodes-base.* vs n8n-nodes-base.*
• ✅ get_node_essentials preferred over get_node_info (5KB vs 100KB+)
• ✅ Validation profiles: minimal/runtime/ai-friendly/strict
• ✅ Smart parameters: branch="true"/"false" for IF, case=N for Switch
• ✅ Auto-sanitization runs on ALL nodes during any update

3. Workflow Patterns (Skill #3)

• ✅ 2,653 real templates available
• ✅ Template metadata includes complexity, setup time, services
• ✅ Common pattern: Trigger → Process → Act (5-7 nodes)
• ✅ Webhook workflows: 27.6% of all workflows

4. Validation Expert (Skill #4)

• ✅ Real validation errors documented
• ✅ Auto-sanitization fixes operator structures
• ✅ Binary operators (equals, contains) vs unary (isEmpty, isNotEmpty)

5. Node Configuration (Skill #5)

• ✅ Property dependencies documented (e.g., sendBody → contentType)
• ✅ Operation-specific requirements vary
• ✅ 8 AI connection types supported

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Tools Availability Summary

Available WITHOUT n8n API:

• search_nodes, list_nodes, get_node_essentials ✅
• validate_node_minimal, validate_node_operation ✅
• validate_workflow, get_property_dependencies ✅
• search_templates, get_template, list_tasks ✅

Requires n8n API (AVAILABLE at n8n-test.n8n-mcp.com):

• n8n_create_workflow ✅
• n8n_update_partial_workflow ✅
• n8n_validate_workflow (by ID) ✅
• n8n_list_workflows, n8n_get_workflow ✅
• n8n_trigger_webhook_workflow ✅

---

Testing Complete: Ready for skill implementation with real data!