n8n-mcp/PHASE_2_TEST_SCENARIOS.md

Phase 2 Validation - Test Scenarios

Quick Verification Tests

After reloading the MCP server, run these tests to verify all Phase 2 fixes work correctly.

---

Test 1: Missing Language Model Detection ✅

Issue: HIGH-01 - AI Agent without language model wasn't validated

Test Workflow:

{
  "name": "Test Missing LM",
  "nodes": [
    {
      "id": "agent1",
      "name": "AI Agent",
      "type": "@n8n/n8n-nodes-langchain.agent",
      "position": [500, 300],
      "parameters": {
        "promptType": "define",
        "text": "You are a helpful assistant"
      },
      "typeVersion": 1.7
    }
  ],
  "connections": {}
}

Expected Result:

valid: false
errors: [
  {
    type: "error",
    message: "AI Agent \"AI Agent\" requires an ai_languageModel connection...",
    code: "MISSING_LANGUAGE_MODEL"
  }
]

Verify: Error is returned with code MISSING_LANGUAGE_MODEL

---

Test 2: AI Tool Connection Detection ✅

Issue: HIGH-04 - False "no tools connected" warning when tools ARE connected

Test Workflow:

{
  "name": "Test Tool Detection",
  "nodes": [
    {
      "id": "openai1",
      "name": "OpenAI Chat Model",
      "type": "@n8n/n8n-nodes-langchain.lmChatOpenAi",
      "position": [200, 300],
      "parameters": {
        "modelName": "gpt-4"
      },
      "typeVersion": 1
    },
    {
      "id": "tool1",
      "name": "HTTP Request Tool",
      "type": "@n8n/n8n-nodes-langchain.toolHttpRequest",
      "position": [200, 400],
      "parameters": {
        "toolDescription": "Calls a weather API",
        "url": "https://api.weather.com"
      },
      "typeVersion": 1.1
    },
    {
      "id": "agent1",
      "name": "AI Agent",
      "type": "@n8n/n8n-nodes-langchain.agent",
      "position": [500, 300],
      "parameters": {
        "promptType": "define",
        "text": "You are a helpful assistant"
      },
      "typeVersion": 1.7
    }
  ],
  "connections": {
    "OpenAI Chat Model": {
      "ai_languageModel": [[{
        "node": "AI Agent",
        "type": "ai_languageModel",
        "index": 0
      }]]
    },
    "HTTP Request Tool": {
      "ai_tool": [[{
        "node": "AI Agent",
        "type": "ai_tool",
        "index": 0
      }]]
    }
  }
}

Expected Result:

valid: true (or only warnings, NO error about missing tools)
warnings: [] (should NOT contain "no ai_tool connections")

Verify: No false warning about missing tools

---

Test 3A: Streaming Mode - Chat Trigger ✅

Issue: HIGH-08 - Streaming mode with main output wasn't validated

Test Workflow:

{
  "name": "Test Streaming Chat Trigger",
  "nodes": [
    {
      "id": "trigger1",
      "name": "Chat Trigger",
      "type": "@n8n/n8n-nodes-langchain.chatTrigger",
      "position": [100, 300],
      "parameters": {
        "options": {
          "responseMode": "streaming"
        }
      },
      "typeVersion": 1
    },
    {
      "id": "openai1",
      "name": "OpenAI Chat Model",
      "type": "@n8n/n8n-nodes-langchain.lmChatOpenAi",
      "position": [300, 200],
      "parameters": {
        "modelName": "gpt-4"
      },
      "typeVersion": 1
    },
    {
      "id": "agent1",
      "name": "AI Agent",
      "type": "@n8n/n8n-nodes-langchain.agent",
      "position": [500, 300],
      "parameters": {
        "promptType": "define",
        "text": "You are a helpful assistant"
      },
      "typeVersion": 1.7
    },
    {
      "id": "response1",
      "name": "Response Node",
      "type": "n8n-nodes-base.respondToWebhook",
      "position": [700, 300],
      "parameters": {},
      "typeVersion": 1
    }
  ],
  "connections": {
    "Chat Trigger": {
      "main": [[{
        "node": "AI Agent",
        "type": "main",
        "index": 0
      }]]
    },
    "OpenAI Chat Model": {
      "ai_languageModel": [[{
        "node": "AI Agent",
        "type": "ai_languageModel",
        "index": 0
      }]]
    },
    "AI Agent": {
      "main": [[{
        "node": "Response Node",
        "type": "main",
        "index": 0
      }]]
    }
  }
}

Expected Result:

valid: false
errors: [
  {
    type: "error",
    message: "AI Agent \"AI Agent\" is in streaming mode... but has outgoing main connections...",
    code: "STREAMING_WITH_MAIN_OUTPUT" or "STREAMING_AGENT_HAS_OUTPUT"
  }
]

Verify: Error about streaming with main output

---

Test 3B: Streaming Mode - AI Agent Own Setting ✅

Issue: HIGH-08 - Streaming mode validation incomplete (only checked Chat Trigger)

Test Workflow:

{
  "name": "Test Streaming AI Agent",
  "nodes": [
    {
      "id": "openai1",
      "name": "OpenAI Chat Model",
      "type": "@n8n/n8n-nodes-langchain.lmChatOpenAi",
      "position": [200, 300],
      "parameters": {
        "modelName": "gpt-4"
      },
      "typeVersion": 1
    },
    {
      "id": "agent1",
      "name": "AI Agent",
      "type": "@n8n/n8n-nodes-langchain.agent",
      "position": [500, 300],
      "parameters": {
        "promptType": "define",
        "text": "You are a helpful assistant",
        "options": {
          "streamResponse": true
        }
      },
      "typeVersion": 1.7
    },
    {
      "id": "response1",
      "name": "Response Node",
      "type": "n8n-nodes-base.respondToWebhook",
      "position": [700, 300],
      "parameters": {},
      "typeVersion": 1
    }
  ],
  "connections": {
    "OpenAI Chat Model": {
      "ai_languageModel": [[{
        "node": "AI Agent",
        "type": "ai_languageModel",
        "index": 0
      }]]
    },
    "AI Agent": {
      "main": [[{
        "node": "Response Node",
        "type": "main",
        "index": 0
      }]]
    }
  }
}

Expected Result:

valid: false
errors: [
  {
    type: "error",
    message: "AI Agent \"AI Agent\" is in streaming mode (has streamResponse=true in options)...",
    code: "STREAMING_WITH_MAIN_OUTPUT"
  }
]

Verify: Detects streaming from AI Agent's own setting, not just Chat Trigger

---

Test 4: get_node_essentials Examples ✅

Issue: MEDIUM-02 - Examples always returned empty array

MCP Call:

get_node_essentials({
  nodeType: "@n8n/n8n-nodes-langchain.agent",
  includeExamples: true
})

Expected Result:

{
  "nodeType": "nodes-langchain.agent",
  "workflowNodeType": "@n8n/n8n-nodes-langchain.agent",
  "displayName": "AI Agent",
  "examples": [
    {
      "configuration": { /* actual config */ },
      "source": {
        "template": "...",
        "views": 99999,
        "complexity": "medium"
      },
      "useCases": ["..."],
      "metadata": {
        "hasCredentials": false,
        "hasExpressions": true
      }
    }
  ],
  "examplesCount": 3
}

Verify:

• examples is an array with length > 0
• Each example has configuration, source, useCases, metadata
• examplesCount matches examples.length

Note: Requires templates to be fetched first:

npm run fetch:templates

---

Test 5: Integration - Multiple Errors ✅

Test Workflow: Combine multiple errors

{
  "name": "Test Multiple Errors",
  "nodes": [
    {
      "id": "trigger1",
      "name": "Chat Trigger",
      "type": "@n8n/n8n-nodes-langchain.chatTrigger",
      "position": [100, 300],
      "parameters": {
        "options": {
          "responseMode": "streaming"
        }
      },
      "typeVersion": 1
    },
    {
      "id": "agent1",
      "name": "AI Agent",
      "type": "@n8n/n8n-nodes-langchain.agent",
      "position": [500, 300],
      "parameters": {
        "promptType": "define",
        "text": "You are a helpful assistant"
      },
      "typeVersion": 1.7
    },
    {
      "id": "response1",
      "name": "Response Node",
      "type": "n8n-nodes-base.respondToWebhook",
      "position": [700, 300],
      "parameters": {},
      "typeVersion": 1
    }
  ],
  "connections": {
    "Chat Trigger": {
      "main": [[{
        "node": "AI Agent",
        "type": "main",
        "index": 0
      }]]
    },
    "AI Agent": {
      "main": [[{
        "node": "Response Node",
        "type": "main",
        "index": 0
      }]]
    }
  }
}

Expected Result:

valid: false
errors: [
  {
    type: "error",
    code: "MISSING_LANGUAGE_MODEL",
    message: "AI Agent \"AI Agent\" requires an ai_languageModel connection..."
  },
  {
    type: "error",
    code: "STREAMING_WITH_MAIN_OUTPUT" or "STREAMING_AGENT_HAS_OUTPUT",
    message: "AI Agent \"AI Agent\" is in streaming mode... but has outgoing main connections..."
  }
]

Verify: Both validation errors are detected and reported

---

How to Run Tests

Option 1: Using MCP Tools (Recommended)

After reloading MCP server, use the validation tools:

// For workflow validation
validate_workflow({
  workflow: { /* paste test workflow JSON */ },
  profile: "ai-friendly"
})

// For examples
get_node_essentials({
  nodeType: "@n8n/n8n-nodes-langchain.agent",
  includeExamples: true
})

Option 2: Using Debug Script

npm run build
npx tsx scripts/test-ai-validation-debug.ts

Option 3: Using n8n-mcp-tester Agent

Ask the n8n-mcp-tester agent to run specific test scenarios from this document.

---

Success Criteria

✅ All 5 test scenarios pass ✅ Error codes match expected values ✅ Error messages are clear and actionable ✅ No false positives or false negatives ✅ Examples retrieval works for AI nodes

---

Fixes Applied

1. Node Type Normalization (21 locations)

   • Changed all comparisons from FULL form to SHORT form
   • Affects: ai-node-validator.ts, ai-tool-validators.ts

2. Streaming Validation Enhancement

   • Added check for AI Agent's own streamResponse setting
   • Previously only checked Chat Trigger streaming

3. Examples Retrieval Consistency

   • Use result.workflowNodeType instead of reconstructing
   • Matches search_nodes behavior

---

Commits

• 92eb4ef: Critical validation fixes (node type normalization)
• 81dfbbb: Examples retrieval fix (workflowNodeType consistency)
• 3ba3f10: Phase 2 completion documentation

Total: 3 commits, ~250 lines changed