feat: implement n8n integration improvements and protocol version negotiation

- Add intelligent protocol version negotiation (2024-11-05 for n8n, 2025-03-26 for standard clients)
- Fix memory leak potential with async cleanup and connection close handling
- Enhance error sanitization for production environments
- Add schema validation for n8n nested output workaround
- Improve Docker security with unpredictable UIDs/GIDs
- Create n8n-friendly tool descriptions to reduce schema validation errors
- Add comprehensive protocol negotiation test suite

Addresses code review feedback:
- Protocol version inconsistency resolved
- Memory management improved
- Error information leakage fixed
- Docker security enhanced

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

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
czlonkowski
2025-08-01 14:23:48 +02:00
parent 6cdb52f56f
commit 3fec6813f3
21 changed files with 2517 additions and 97 deletions

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@@ -1,36 +0,0 @@
# n8n-mcp Docker Environment Configuration
# Copy this file to .env and customize for your deployment
# === n8n Configuration ===
# n8n basic auth (change these in production!)
N8N_BASIC_AUTH_ACTIVE=true
N8N_BASIC_AUTH_USER=admin
N8N_BASIC_AUTH_PASSWORD=changeme
# n8n host configuration
N8N_HOST=localhost
N8N_PORT=5678
N8N_PROTOCOL=http
N8N_WEBHOOK_URL=http://localhost:5678/
# n8n encryption key (generate with: openssl rand -hex 32)
N8N_ENCRYPTION_KEY=03ce3b083dce12577b8ba7889c57844ca3fe6557c8394bb67183c05357b418f9
# === n8n-mcp Configuration ===
# MCP server port
MCP_PORT=3000
# MCP authentication token (generate with: openssl rand -hex 32)
MCP_AUTH_TOKEN=0dcead8b41afe4d26bbe93d6e78784c974427a8b8db572ee356d976ec82d13f7
# n8n API key for MCP to access n8n
# Get this from n8n UI: Settings > n8n API > Create API Key
N8N_API_KEY=
# Logging level (debug, info, warn, error)
LOG_LEVEL=info
# === GitHub Container Registry (for CI/CD) ===
# Only needed if building custom images
GITHUB_REPOSITORY=czlonkowski/n8n-mcp
VERSION=latest

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@@ -57,9 +57,13 @@ LABEL org.opencontainers.image.description="n8n MCP Server - Runtime Only"
LABEL org.opencontainers.image.licenses="MIT"
LABEL org.opencontainers.image.title="n8n-mcp"
# Create non-root user
RUN addgroup -g 1001 -S nodejs && \
adduser -S nodejs -u 1001 && \
# Create non-root user with unpredictable UID/GID
# Using a hash of the build time to generate unpredictable IDs
RUN BUILD_HASH=$(date +%s | sha256sum | head -c 8) && \
UID=$((10000 + 0x${BUILD_HASH} % 50000)) && \
GID=$((10000 + 0x${BUILD_HASH} % 50000)) && \
addgroup -g ${GID} -S nodejs && \
adduser -S nodejs -u ${UID} -G nodejs && \
chown -R nodejs:nodejs /app
# Switch to non-root user

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@@ -29,9 +29,13 @@ RUN apk add --no-cache \
tini \
&& rm -rf /var/cache/apk/*
# Create non-root user with less common UID/GID
RUN addgroup -g 1001 n8n-mcp && \
adduser -u 1001 -G n8n-mcp -s /bin/sh -D n8n-mcp
# Create non-root user with unpredictable UID/GID
# Using a hash of the build time to generate unpredictable IDs
RUN BUILD_HASH=$(date +%s | sha256sum | head -c 8) && \
UID=$((10000 + 0x${BUILD_HASH} % 50000)) && \
GID=$((10000 + 0x${BUILD_HASH} % 50000)) && \
addgroup -g ${GID} n8n-mcp && \
adduser -u ${UID} -G n8n-mcp -s /bin/sh -D n8n-mcp
# Set working directory
WORKDIR /app

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162
docs/issue-90-findings.md Normal file
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@@ -0,0 +1,162 @@
# Issue #90: "propertyValues[itemName] is not iterable" Error - Research Findings
## Executive Summary
The error "propertyValues[itemName] is not iterable" occurs when AI agents create workflows with incorrect data structures for n8n nodes that use `fixedCollection` properties. This primarily affects Switch Node v2, If Node, and Filter Node. The error prevents workflows from loading in the n8n UI, resulting in empty canvases.
## Root Cause Analysis
### 1. Data Structure Mismatch
The error occurs when n8n's validation engine expects an iterable array but encounters a non-iterable object. This happens with nodes using `fixedCollection` type properties.
**Incorrect Structure (causes error):**
```json
{
"rules": {
"conditions": {
"values": [
{
"value1": "={{$json.status}}",
"operation": "equals",
"value2": "active"
}
]
}
}
}
```
**Correct Structure:**
```json
{
"rules": {
"conditions": [
{
"value1": "={{$json.status}}",
"operation": "equals",
"value2": "active"
}
]
}
}
```
### 2. Affected Nodes
Based on the research and issue comments, the following nodes are affected:
1. **Switch Node v2** (`n8n-nodes-base.switch` with typeVersion: 2)
- Uses `rules` parameter with `conditions` fixedCollection
- v3 doesn't have this issue due to restructured schema
2. **If Node** (`n8n-nodes-base.if` with typeVersion: 1)
- Uses `conditions` parameter with nested conditions array
- Similar structure to Switch v2
3. **Filter Node** (`n8n-nodes-base.filter`)
- Uses `conditions` parameter
- Same fixedCollection pattern
### 3. Why AI Agents Create Incorrect Structures
1. **Training Data Issues**: AI models may have been trained on outdated or incorrect n8n workflow examples
2. **Nested Object Inference**: AI tends to create unnecessarily nested structures when it sees collection-type parameters
3. **Legacy Format Confusion**: Mixing v2 and v3 Switch node formats
4. **Schema Misinterpretation**: The term "fixedCollection" may lead AI to create object wrappers
## Current Impact
From issue #90 comments:
- Multiple users experiencing the issue
- Workflows fail to load completely (empty canvas)
- Users resort to using Switch Node v3 or direct API calls
- The issue appears in "most MCPs" according to user feedback
## Recommended Actions
### 1. Immediate Validation Enhancement
Add specific validation for fixedCollection properties in the workflow validator:
```typescript
// In workflow-validator.ts or enhanced-config-validator.ts
function validateFixedCollectionParameters(node, result) {
const problematicNodes = {
'n8n-nodes-base.switch': { version: 2, fields: ['rules'] },
'n8n-nodes-base.if': { version: 1, fields: ['conditions'] },
'n8n-nodes-base.filter': { version: 1, fields: ['conditions'] }
};
const nodeConfig = problematicNodes[node.type];
if (nodeConfig && node.typeVersion === nodeConfig.version) {
// Validate structure
}
}
```
### 2. Enhanced MCP Tool Validation
Update the validation tools to detect and prevent this specific error pattern:
1. **In `validate_node_operation` tool**: Add checks for fixedCollection structures
2. **In `validate_workflow` tool**: Include specific validation for Switch/If nodes
3. **In `n8n_create_workflow` tool**: Pre-validate parameters before submission
### 3. AI-Friendly Examples
Update workflow examples to show correct structures:
```typescript
// In workflow-examples.ts
export const SWITCH_NODE_EXAMPLE = {
name: "Switch",
type: "n8n-nodes-base.switch",
typeVersion: 3, // Prefer v3 over v2
parameters: {
// Correct v3 structure
}
};
```
### 4. Migration Strategy
For existing workflows with Switch v2:
1. Detect Switch v2 nodes in validation
2. Suggest migration to v3
3. Provide automatic conversion utility
### 5. Documentation Updates
1. Add warnings about fixedCollection structures in tool documentation
2. Include specific examples of correct vs incorrect structures
3. Document the Switch v2 to v3 migration path
## Proposed Implementation Priority
1. **High Priority**: Add validation to prevent creation of invalid structures
2. **High Priority**: Update existing validation tools to catch this error
3. **Medium Priority**: Add auto-fix capabilities to correct structures
4. **Medium Priority**: Update examples and documentation
5. **Low Priority**: Create migration utilities for v2 to v3
## Testing Strategy
1. Create test cases for each affected node type
2. Test both correct and incorrect structures
3. Verify validation catches all variants of the error
4. Test auto-fix suggestions work correctly
## Success Metrics
- Zero instances of "propertyValues[itemName] is not iterable" in newly created workflows
- Clear error messages that guide users to correct structures
- Successful validation of all Switch/If node configurations before workflow creation
## Next Steps
1. Implement validation enhancements in the workflow validator
2. Update MCP tools to include these validations
3. Add comprehensive tests
4. Update documentation with clear examples
5. Consider adding a migration tool for existing workflows

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@@ -40,6 +40,7 @@
"fetch:templates:robust": "node dist/scripts/fetch-templates-robust.js",
"prebuild:fts5": "npx tsx scripts/prebuild-fts5.ts",
"test:templates": "node dist/scripts/test-templates.js",
"test:protocol-negotiation": "npx tsx src/scripts/test-protocol-negotiation.ts",
"test:workflow-validation": "node dist/scripts/test-workflow-validation.js",
"test:template-validation": "node dist/scripts/test-template-validation.js",
"test:essentials": "node dist/scripts/test-essentials.js",

327
scripts/debug-n8n-mode.js Normal file
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@@ -0,0 +1,327 @@
#!/usr/bin/env node
/**
* Debug script for n8n integration issues
* Tests MCP protocol compliance and identifies schema validation problems
*/
const http = require('http');
const crypto = require('crypto');
const MCP_PORT = process.env.MCP_PORT || 3001;
const AUTH_TOKEN = process.env.AUTH_TOKEN || 'test-token-for-n8n-testing-minimum-32-chars';
console.log('🔍 Debugging n8n MCP Integration Issues');
console.log('=====================================\n');
// Test data for different MCP protocol calls
const testCases = [
{
name: 'MCP Initialize',
path: '/mcp',
method: 'POST',
data: {
jsonrpc: '2.0',
method: 'initialize',
params: {
protocolVersion: '2025-03-26',
capabilities: {
tools: {}
},
clientInfo: {
name: 'n8n-debug-test',
version: '1.0.0'
}
},
id: 1
}
},
{
name: 'Tools List',
path: '/mcp',
method: 'POST',
sessionId: null, // Will be set after initialize
data: {
jsonrpc: '2.0',
method: 'tools/list',
params: {},
id: 2
}
},
{
name: 'Tools Call - tools_documentation',
path: '/mcp',
method: 'POST',
sessionId: null, // Will be set after initialize
data: {
jsonrpc: '2.0',
method: 'tools/call',
params: {
name: 'tools_documentation',
arguments: {}
},
id: 3
}
},
{
name: 'Tools Call - get_node_essentials',
path: '/mcp',
method: 'POST',
sessionId: null, // Will be set after initialize
data: {
jsonrpc: '2.0',
method: 'tools/call',
params: {
name: 'get_node_essentials',
arguments: {
nodeType: 'nodes-base.httpRequest'
}
},
id: 4
}
}
];
async function makeRequest(testCase) {
return new Promise((resolve, reject) => {
const data = JSON.stringify(testCase.data);
const options = {
hostname: 'localhost',
port: MCP_PORT,
path: testCase.path,
method: testCase.method,
headers: {
'Content-Type': 'application/json',
'Content-Length': Buffer.byteLength(data),
'Authorization': `Bearer ${AUTH_TOKEN}`,
'Accept': 'application/json, text/event-stream' // Fix for StreamableHTTPServerTransport
}
};
// Add session ID header if available
if (testCase.sessionId) {
options.headers['Mcp-Session-Id'] = testCase.sessionId;
}
console.log(`📤 Making request: ${testCase.name}`);
console.log(` Method: ${testCase.method} ${testCase.path}`);
if (testCase.sessionId) {
console.log(` Session-ID: ${testCase.sessionId}`);
}
console.log(` Data: ${data}`);
const req = http.request(options, (res) => {
let responseData = '';
console.log(`📥 Response Status: ${res.statusCode}`);
console.log(` Headers:`, res.headers);
res.on('data', (chunk) => {
responseData += chunk;
});
res.on('end', () => {
try {
let parsed;
// Handle SSE format response
if (responseData.startsWith('event: message\ndata: ')) {
const dataLine = responseData.split('\n').find(line => line.startsWith('data: '));
if (dataLine) {
const jsonData = dataLine.substring(6); // Remove 'data: '
parsed = JSON.parse(jsonData);
} else {
throw new Error('Could not extract JSON from SSE response');
}
} else {
parsed = JSON.parse(responseData);
}
resolve({
statusCode: res.statusCode,
headers: res.headers,
data: parsed,
raw: responseData
});
} catch (e) {
resolve({
statusCode: res.statusCode,
headers: res.headers,
data: null,
raw: responseData,
parseError: e.message
});
}
});
});
req.on('error', (err) => {
reject(err);
});
req.write(data);
req.end();
});
}
async function validateMCPResponse(testCase, response) {
console.log(`✅ Validating response for: ${testCase.name}`);
const issues = [];
// Check HTTP status
if (response.statusCode !== 200) {
issues.push(`❌ Expected HTTP 200, got ${response.statusCode}`);
}
// Check JSON-RPC structure
if (!response.data) {
issues.push(`❌ Response is not valid JSON: ${response.parseError}`);
return issues;
}
if (response.data.jsonrpc !== '2.0') {
issues.push(`❌ Missing or invalid jsonrpc field: ${response.data.jsonrpc}`);
}
if (response.data.id !== testCase.data.id) {
issues.push(`❌ ID mismatch: expected ${testCase.data.id}, got ${response.data.id}`);
}
// Method-specific validation
if (testCase.data.method === 'initialize') {
if (!response.data.result) {
issues.push(`❌ Initialize response missing result field`);
} else {
if (!response.data.result.protocolVersion) {
issues.push(`❌ Initialize response missing protocolVersion`);
} else if (response.data.result.protocolVersion !== '2025-03-26') {
issues.push(`❌ Protocol version mismatch: expected 2025-03-26, got ${response.data.result.protocolVersion}`);
}
if (!response.data.result.capabilities) {
issues.push(`❌ Initialize response missing capabilities`);
}
if (!response.data.result.serverInfo) {
issues.push(`❌ Initialize response missing serverInfo`);
}
}
// Extract session ID for subsequent requests
if (response.headers['mcp-session-id']) {
console.log(`📋 Session ID: ${response.headers['mcp-session-id']}`);
return { issues, sessionId: response.headers['mcp-session-id'] };
} else {
issues.push(`❌ Initialize response missing Mcp-Session-Id header`);
}
}
if (testCase.data.method === 'tools/list') {
if (!response.data.result || !response.data.result.tools) {
issues.push(`❌ Tools list response missing tools array`);
} else {
console.log(`📋 Found ${response.data.result.tools.length} tools`);
}
}
if (testCase.data.method === 'tools/call') {
if (!response.data.result) {
issues.push(`❌ Tool call response missing result field`);
} else if (!response.data.result.content) {
issues.push(`❌ Tool call response missing content array`);
} else if (!Array.isArray(response.data.result.content)) {
issues.push(`❌ Tool call response content is not an array`);
} else {
// Validate content structure
for (let i = 0; i < response.data.result.content.length; i++) {
const content = response.data.result.content[i];
if (!content.type) {
issues.push(`❌ Content item ${i} missing type field`);
}
if (content.type === 'text' && !content.text) {
issues.push(`❌ Text content item ${i} missing text field`);
}
}
}
}
if (issues.length === 0) {
console.log(`${testCase.name} validation passed`);
} else {
console.log(`${testCase.name} validation failed:`);
issues.forEach(issue => console.log(` ${issue}`));
}
return { issues };
}
async function runTests() {
console.log('Starting MCP protocol compliance tests...\n');
let sessionId = null;
let allIssues = [];
for (const testCase of testCases) {
try {
// Set session ID from previous test
if (sessionId && testCase.name !== 'MCP Initialize') {
testCase.sessionId = sessionId;
}
const response = await makeRequest(testCase);
console.log(`📄 Raw Response: ${response.raw}\n`);
const validation = await validateMCPResponse(testCase, response);
if (validation.sessionId) {
sessionId = validation.sessionId;
}
allIssues.push(...validation.issues);
console.log('─'.repeat(50));
} catch (error) {
console.error(`❌ Request failed for ${testCase.name}:`, error.message);
allIssues.push(`Request failed for ${testCase.name}: ${error.message}`);
}
}
// Summary
console.log('\n📊 SUMMARY');
console.log('==========');
if (allIssues.length === 0) {
console.log('🎉 All tests passed! MCP protocol compliance looks good.');
} else {
console.log(`❌ Found ${allIssues.length} issues:`);
allIssues.forEach((issue, i) => {
console.log(` ${i + 1}. ${issue}`);
});
}
console.log('\n🔍 Recommendations:');
console.log('1. Check MCP server logs at /tmp/mcp-server.log');
console.log('2. Verify protocol version consistency (should be 2025-03-26)');
console.log('3. Ensure tool schemas match MCP specification exactly');
console.log('4. Test with actual n8n MCP Client Tool node');
}
// Check if MCP server is running
console.log(`Checking if MCP server is running at localhost:${MCP_PORT}...`);
const healthCheck = http.get(`http://localhost:${MCP_PORT}/health`, (res) => {
if (res.statusCode === 200) {
console.log('✅ MCP server is running\n');
runTests().catch(console.error);
} else {
console.error('❌ MCP server health check failed:', res.statusCode);
process.exit(1);
}
}).on('error', (err) => {
console.error('❌ MCP server is not running. Please start it first:', err.message);
console.error('Use: npm run start:n8n');
process.exit(1);
});

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@@ -3,6 +3,27 @@
# Script to test n8n integration with n8n-mcp server
set -e
# Check for command line arguments
if [ "$1" == "--clear-api-key" ] || [ "$1" == "-c" ]; then
echo "🗑️ Clearing saved n8n API key..."
rm -f "$HOME/.n8n-mcp-test/.n8n-api-key"
echo "✅ API key cleared. You'll be prompted for a new key on next run."
exit 0
fi
if [ "$1" == "--help" ] || [ "$1" == "-h" ]; then
echo "Usage: $0 [options]"
echo ""
echo "Options:"
echo " -h, --help Show this help message"
echo " -c, --clear-api-key Clear the saved n8n API key"
echo ""
echo "The script will save your n8n API key on first use and reuse it on"
echo "subsequent runs. You can override the saved key at runtime or clear"
echo "it with the --clear-api-key option."
exit 0
fi
echo "🚀 Starting n8n integration test environment..."
# Colors for output
@@ -19,6 +40,8 @@ AUTH_TOKEN="test-token-for-n8n-testing-minimum-32-chars"
# n8n data directory for persistence
N8N_DATA_DIR="$HOME/.n8n-mcp-test"
# API key storage file
API_KEY_FILE="$N8N_DATA_DIR/.n8n-api-key"
# Function to detect OS
detect_os() {
@@ -199,6 +222,34 @@ for i in {1..30}; do
sleep 1
done
# Check for saved API key
if [ -f "$API_KEY_FILE" ]; then
# Read saved API key
N8N_API_KEY=$(cat "$API_KEY_FILE" 2>/dev/null || echo "")
if [ -n "$N8N_API_KEY" ]; then
echo -e "\n${GREEN}✅ Using saved n8n API key${NC}"
echo -e "${YELLOW} To use a different key, delete: ${API_KEY_FILE}${NC}"
# Give user a chance to override
echo -e "\n${YELLOW}Press Enter to continue with saved key, or paste a new API key:${NC}"
read -r NEW_API_KEY
if [ -n "$NEW_API_KEY" ]; then
N8N_API_KEY="$NEW_API_KEY"
# Save the new key
echo "$N8N_API_KEY" > "$API_KEY_FILE"
chmod 600 "$API_KEY_FILE"
echo -e "${GREEN}✅ New API key saved${NC}"
fi
else
# File exists but is empty, remove it
rm -f "$API_KEY_FILE"
fi
fi
# If no saved key, prompt for one
if [ -z "$N8N_API_KEY" ]; then
# Guide user to get API key
echo -e "\n${BLUE}━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━${NC}"
echo -e "${YELLOW}🔑 n8n API Key Setup${NC}"
@@ -219,6 +270,14 @@ echo -e "${BLUE}━━━━━━━━━━━━━━━━━━━━━
echo -e "\n${YELLOW}Please paste your n8n API key here (or press Enter to skip):${NC}"
read -r N8N_API_KEY
# Save the API key if provided
if [ -n "$N8N_API_KEY" ]; then
echo "$N8N_API_KEY" > "$API_KEY_FILE"
chmod 600 "$API_KEY_FILE"
echo -e "${GREEN}✅ API key saved for future use${NC}"
fi
fi
# Check if API key was provided
if [ -z "$N8N_API_KEY" ]; then
echo -e "${YELLOW}⚠️ No API key provided. n8n management tools will not be available.${NC}"

95
scripts/test-n8n-mode.sh Executable file
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@@ -0,0 +1,95 @@
#!/bin/bash
# Test script for n8n MCP integration fixes
set -e
echo "🔧 Testing n8n MCP Integration Fixes"
echo "===================================="
# Configuration
MCP_PORT=${MCP_PORT:-3001}
AUTH_TOKEN=${AUTH_TOKEN:-"test-token-for-n8n-testing-minimum-32-chars"}
# Colors
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
RED='\033[0;31m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color
# Cleanup function
cleanup() {
echo -e "\n${YELLOW}🧹 Cleaning up...${NC}"
if [ -n "$MCP_PID" ] && kill -0 $MCP_PID 2>/dev/null; then
echo "Stopping MCP server..."
kill $MCP_PID 2>/dev/null || true
wait $MCP_PID 2>/dev/null || true
fi
echo -e "${GREEN}✅ Cleanup complete${NC}"
}
trap cleanup EXIT INT TERM
# Check if we're in the right directory
if [ ! -f "package.json" ] || [ ! -d "dist" ]; then
echo -e "${RED}❌ Error: Must run from n8n-mcp directory${NC}"
exit 1
fi
# Build the project (our fixes)
echo -e "${YELLOW}📦 Building project with fixes...${NC}"
npm run build
# Start MCP server in n8n mode
echo -e "\n${GREEN}🚀 Starting MCP server in n8n mode...${NC}"
N8N_MODE=true \
MCP_MODE=http \
AUTH_TOKEN="${AUTH_TOKEN}" \
PORT=${MCP_PORT} \
DEBUG_MCP=true \
node dist/mcp/index.js > /tmp/mcp-n8n-test.log 2>&1 &
MCP_PID=$!
echo -e "${YELLOW}📄 MCP server logs: /tmp/mcp-n8n-test.log${NC}"
# Wait for server to start
echo -e "${YELLOW}⏳ Waiting for MCP server to start...${NC}"
for i in {1..15}; do
if curl -s http://localhost:${MCP_PORT}/health >/dev/null 2>&1; then
echo -e "${GREEN}✅ MCP server is ready!${NC}"
break
fi
if [ $i -eq 15 ]; then
echo -e "${RED}❌ MCP server failed to start${NC}"
echo "Server logs:"
cat /tmp/mcp-n8n-test.log
exit 1
fi
sleep 1
done
# Test the protocol fixes
echo -e "\n${BLUE}🧪 Testing protocol fixes...${NC}"
# Run our debug script
echo -e "${YELLOW}Running comprehensive MCP protocol tests...${NC}"
node scripts/debug-n8n-mode.js
echo -e "\n${GREEN}🎉 Test complete!${NC}"
echo -e "\n📋 Summary of fixes applied:"
echo -e " ✅ Fixed protocol version mismatch (now using 2025-03-26)"
echo -e " ✅ Enhanced tool response formatting and size validation"
echo -e " ✅ Added comprehensive parameter validation"
echo -e " ✅ Improved error handling and logging"
echo -e " ✅ Added initialization request debugging"
echo -e "\n📝 Next steps:"
echo -e " 1. If tests pass, the n8n schema validation errors should be resolved"
echo -e " 2. Test with actual n8n MCP Client Tool node"
echo -e " 3. Monitor logs at /tmp/mcp-n8n-test.log for any remaining issues"
echo -e "\n${YELLOW}Press any key to view recent server logs, or Ctrl+C to exit...${NC}"
read -n 1
echo -e "\n${BLUE}📄 Recent server logs:${NC}"
tail -50 /tmp/mcp-n8n-test.log

428
scripts/test-n8n-mode.ts Normal file
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@@ -0,0 +1,428 @@
#!/usr/bin/env ts-node
/**
* TypeScript test script for n8n MCP integration fixes
* Tests the protocol changes and identifies any remaining issues
*/
import http from 'http';
import { spawn, ChildProcess } from 'child_process';
import path from 'path';
interface TestResult {
name: string;
passed: boolean;
error?: string;
response?: any;
}
class N8nMcpTester {
private mcpProcess: ChildProcess | null = null;
private readonly mcpPort = 3001;
private readonly authToken = 'test-token-for-n8n-testing-minimum-32-chars';
private sessionId: string | null = null;
async start(): Promise<void> {
console.log('🔧 Testing n8n MCP Integration Fixes');
console.log('====================================\n');
try {
await this.startMcpServer();
await this.runTests();
} finally {
await this.cleanup();
}
}
private async startMcpServer(): Promise<void> {
console.log('📦 Starting MCP server in n8n mode...');
const projectRoot = path.resolve(__dirname, '..');
this.mcpProcess = spawn('node', ['dist/mcp/index.js'], {
cwd: projectRoot,
env: {
...process.env,
N8N_MODE: 'true',
MCP_MODE: 'http',
AUTH_TOKEN: this.authToken,
PORT: this.mcpPort.toString(),
DEBUG_MCP: 'true'
},
stdio: ['ignore', 'pipe', 'pipe']
});
// Log server output
this.mcpProcess.stdout?.on('data', (data) => {
console.log(`[MCP] ${data.toString().trim()}`);
});
this.mcpProcess.stderr?.on('data', (data) => {
console.error(`[MCP ERROR] ${data.toString().trim()}`);
});
// Wait for server to be ready
await this.waitForServer();
}
private async waitForServer(): Promise<void> {
console.log('⏳ Waiting for MCP server to be ready...');
for (let i = 0; i < 30; i++) {
try {
await this.makeHealthCheck();
console.log('✅ MCP server is ready!\n');
return;
} catch (error) {
if (i === 29) {
throw new Error('MCP server failed to start within 30 seconds');
}
await this.sleep(1000);
}
}
}
private makeHealthCheck(): Promise<void> {
return new Promise((resolve, reject) => {
const req = http.get(`http://localhost:${this.mcpPort}/health`, (res) => {
if (res.statusCode === 200) {
resolve();
} else {
reject(new Error(`Health check failed: ${res.statusCode}`));
}
});
req.on('error', reject);
req.setTimeout(5000, () => {
req.destroy();
reject(new Error('Health check timeout'));
});
});
}
private async runTests(): Promise<void> {
const tests: TestResult[] = [];
// Test 1: Initialize with correct protocol version
tests.push(await this.testInitialize());
// Test 2: List tools
tests.push(await this.testListTools());
// Test 3: Call tools_documentation
tests.push(await this.testToolCall('tools_documentation', {}));
// Test 4: Call get_node_essentials with parameters
tests.push(await this.testToolCall('get_node_essentials', {
nodeType: 'nodes-base.httpRequest'
}));
// Test 5: Call with invalid parameters (should handle gracefully)
tests.push(await this.testToolCallInvalid());
this.printResults(tests);
}
private async testInitialize(): Promise<TestResult> {
console.log('🧪 Testing MCP Initialize...');
try {
const response = await this.makeRequest('POST', '/mcp', {
jsonrpc: '2.0',
method: 'initialize',
params: {
protocolVersion: '2025-03-26',
capabilities: { tools: {} },
clientInfo: { name: 'n8n-test', version: '1.0.0' }
},
id: 1
});
if (response.statusCode !== 200) {
return {
name: 'Initialize',
passed: false,
error: `HTTP ${response.statusCode}`
};
}
const data = JSON.parse(response.body);
// Extract session ID
this.sessionId = response.headers['mcp-session-id'] as string;
if (data.result?.protocolVersion === '2025-03-26') {
return {
name: 'Initialize',
passed: true,
response: data
};
} else {
return {
name: 'Initialize',
passed: false,
error: `Wrong protocol version: ${data.result?.protocolVersion}`,
response: data
};
}
} catch (error) {
return {
name: 'Initialize',
passed: false,
error: error instanceof Error ? error.message : 'Unknown error'
};
}
}
private async testListTools(): Promise<TestResult> {
console.log('🧪 Testing Tools List...');
try {
const response = await this.makeRequest('POST', '/mcp', {
jsonrpc: '2.0',
method: 'tools/list',
params: {},
id: 2
}, this.sessionId);
if (response.statusCode !== 200) {
return {
name: 'List Tools',
passed: false,
error: `HTTP ${response.statusCode}`
};
}
const data = JSON.parse(response.body);
if (data.result?.tools && Array.isArray(data.result.tools)) {
return {
name: 'List Tools',
passed: true,
response: { toolCount: data.result.tools.length }
};
} else {
return {
name: 'List Tools',
passed: false,
error: 'Missing or invalid tools array',
response: data
};
}
} catch (error) {
return {
name: 'List Tools',
passed: false,
error: error instanceof Error ? error.message : 'Unknown error'
};
}
}
private async testToolCall(toolName: string, args: any): Promise<TestResult> {
console.log(`🧪 Testing Tool Call: ${toolName}...`);
try {
const response = await this.makeRequest('POST', '/mcp', {
jsonrpc: '2.0',
method: 'tools/call',
params: {
name: toolName,
arguments: args
},
id: 3
}, this.sessionId);
if (response.statusCode !== 200) {
return {
name: `Tool Call: ${toolName}`,
passed: false,
error: `HTTP ${response.statusCode}`
};
}
const data = JSON.parse(response.body);
if (data.result?.content && Array.isArray(data.result.content)) {
return {
name: `Tool Call: ${toolName}`,
passed: true,
response: { contentItems: data.result.content.length }
};
} else {
return {
name: `Tool Call: ${toolName}`,
passed: false,
error: 'Missing or invalid content array',
response: data
};
}
} catch (error) {
return {
name: `Tool Call: ${toolName}`,
passed: false,
error: error instanceof Error ? error.message : 'Unknown error'
};
}
}
private async testToolCallInvalid(): Promise<TestResult> {
console.log('🧪 Testing Tool Call with invalid parameters...');
try {
const response = await this.makeRequest('POST', '/mcp', {
jsonrpc: '2.0',
method: 'tools/call',
params: {
name: 'get_node_essentials',
arguments: {} // Missing required nodeType parameter
},
id: 4
}, this.sessionId);
if (response.statusCode !== 200) {
return {
name: 'Tool Call: Invalid Params',
passed: false,
error: `HTTP ${response.statusCode}`
};
}
const data = JSON.parse(response.body);
// Should either return an error response or handle gracefully
if (data.error || (data.result?.isError && data.result?.content)) {
return {
name: 'Tool Call: Invalid Params',
passed: true,
response: { handledGracefully: true }
};
} else {
return {
name: 'Tool Call: Invalid Params',
passed: false,
error: 'Did not handle invalid parameters properly',
response: data
};
}
} catch (error) {
return {
name: 'Tool Call: Invalid Params',
passed: false,
error: error instanceof Error ? error.message : 'Unknown error'
};
}
}
private makeRequest(method: string, path: string, data?: any, sessionId?: string | null): Promise<{
statusCode: number;
headers: http.IncomingHttpHeaders;
body: string;
}> {
return new Promise((resolve, reject) => {
const postData = data ? JSON.stringify(data) : '';
const options: http.RequestOptions = {
hostname: 'localhost',
port: this.mcpPort,
path,
method,
headers: {
'Content-Type': 'application/json',
'Authorization': `Bearer ${this.authToken}`,
...(postData && { 'Content-Length': Buffer.byteLength(postData) }),
...(sessionId && { 'Mcp-Session-Id': sessionId })
}
};
const req = http.request(options, (res) => {
let body = '';
res.on('data', (chunk) => body += chunk);
res.on('end', () => {
resolve({
statusCode: res.statusCode || 0,
headers: res.headers,
body
});
});
});
req.on('error', reject);
req.setTimeout(10000, () => {
req.destroy();
reject(new Error('Request timeout'));
});
if (postData) {
req.write(postData);
}
req.end();
});
}
private printResults(tests: TestResult[]): void {
console.log('\n📊 TEST RESULTS');
console.log('================');
const passed = tests.filter(t => t.passed).length;
const total = tests.length;
tests.forEach(test => {
const status = test.passed ? '✅' : '❌';
console.log(`${status} ${test.name}`);
if (!test.passed && test.error) {
console.log(` Error: ${test.error}`);
}
if (test.response) {
console.log(` Response: ${JSON.stringify(test.response, null, 2)}`);
}
});
console.log(`\n📈 Summary: ${passed}/${total} tests passed`);
if (passed === total) {
console.log('🎉 All tests passed! The n8n integration fixes should resolve the schema validation errors.');
} else {
console.log('❌ Some tests failed. Please review the errors above.');
}
}
private async cleanup(): Promise<void> {
console.log('\n🧹 Cleaning up...');
if (this.mcpProcess) {
this.mcpProcess.kill('SIGTERM');
// Wait for graceful shutdown
await new Promise<void>((resolve) => {
if (!this.mcpProcess) {
resolve();
return;
}
const timeout = setTimeout(() => {
this.mcpProcess?.kill('SIGKILL');
resolve();
}, 5000);
this.mcpProcess.on('exit', () => {
clearTimeout(timeout);
resolve();
});
});
}
console.log('✅ Cleanup complete');
}
private sleep(ms: number): Promise<void> {
return new Promise(resolve => setTimeout(resolve, ms));
}
}
// Run the tests
if (require.main === module) {
const tester = new N8nMcpTester();
tester.start().catch(console.error);
}
export { N8nMcpTester };

View File

@@ -16,11 +16,16 @@ import { getStartupBaseUrl, formatEndpointUrls, detectBaseUrl } from './utils/ur
import { PROJECT_VERSION } from './utils/version';
import { v4 as uuidv4 } from 'uuid';
import { isInitializeRequest } from '@modelcontextprotocol/sdk/types.js';
import {
negotiateProtocolVersion,
logProtocolNegotiation,
STANDARD_PROTOCOL_VERSION
} from './utils/protocol-version';
dotenv.config();
// Protocol version constant
const PROTOCOL_VERSION = '2024-11-05';
// Protocol version constant - will be negotiated per client
const DEFAULT_PROTOCOL_VERSION = STANDARD_PROTOCOL_VERSION;
// Session management constants
const MAX_SESSIONS = 100;
@@ -67,8 +72,12 @@ export class SingleSessionHTTPServer {
* Start periodic session cleanup
*/
private startSessionCleanup(): void {
this.cleanupTimer = setInterval(() => {
this.cleanupExpiredSessions();
this.cleanupTimer = setInterval(async () => {
try {
await this.cleanupExpiredSessions();
} catch (error) {
logger.error('Error during session cleanup', error);
}
}, SESSION_CLEANUP_INTERVAL);
logger.info('Session cleanup started', {
@@ -150,6 +159,40 @@ export class SingleSessionHTTPServer {
return uuidv4Regex.test(sessionId);
}
/**
* Sanitize error information for client responses
*/
private sanitizeErrorForClient(error: unknown): { message: string; code: string } {
const isProduction = process.env.NODE_ENV === 'production';
if (error instanceof Error) {
// In production, only return generic messages
if (isProduction) {
// Map known error types to safe messages
if (error.message.includes('Unauthorized') || error.message.includes('authentication')) {
return { message: 'Authentication failed', code: 'AUTH_ERROR' };
}
if (error.message.includes('Session') || error.message.includes('session')) {
return { message: 'Session error', code: 'SESSION_ERROR' };
}
if (error.message.includes('Invalid') || error.message.includes('validation')) {
return { message: 'Validation error', code: 'VALIDATION_ERROR' };
}
// Default generic error
return { message: 'Internal server error', code: 'INTERNAL_ERROR' };
}
// In development, return more details but no stack traces
return {
message: error.message.substring(0, 200), // Limit message length
code: error.name || 'ERROR'
};
}
// For non-Error objects
return { message: 'An error occurred', code: 'UNKNOWN_ERROR' };
}
/**
* Update session last access time
*/
@@ -304,11 +347,12 @@ export class SingleSessionHTTPServer {
// For initialize requests: always create new transport and server
logger.info('handleRequest: Creating new transport for initialize request');
const newSessionId = uuidv4();
// Use client-provided session ID or generate one if not provided
const sessionIdToUse = sessionId || uuidv4();
const server = new N8NDocumentationMCPServer();
transport = new StreamableHTTPServerTransport({
sessionIdGenerator: () => newSessionId,
sessionIdGenerator: () => sessionIdToUse,
onsessioninitialized: (initializedSessionId: string) => {
// Store both transport and server by session ID when session is initialized
logger.info('handleRequest: Session initialized, storing transport and server', {
@@ -415,11 +459,16 @@ export class SingleSessionHTTPServer {
});
if (!res.headersSent) {
// Send sanitized error to client
const sanitizedError = this.sanitizeErrorForClient(error);
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: error instanceof Error ? error.message : 'Internal server error'
message: sanitizedError.message,
data: {
code: sanitizedError.code
}
},
id: req.body?.id || null
});
@@ -618,12 +667,22 @@ export class SingleSessionHTTPServer {
bodyContent: req.body ? JSON.stringify(req.body, null, 2) : 'undefined'
});
// Negotiate protocol version for test endpoint
const negotiationResult = negotiateProtocolVersion(
undefined, // no client version in test
undefined, // no client info
req.get('user-agent'),
req.headers
);
logProtocolNegotiation(negotiationResult, logger, 'TEST_ENDPOINT');
// Test what a basic MCP initialize request should look like
const testResponse = {
jsonrpc: '2.0',
id: req.body?.id || 1,
result: {
protocolVersion: PROTOCOL_VERSION,
protocolVersion: negotiationResult.version,
capabilities: {
tools: {}
},
@@ -681,8 +740,18 @@ export class SingleSessionHTTPServer {
// In n8n mode, return protocol version and server info
if (process.env.N8N_MODE === 'true') {
// Negotiate protocol version for n8n mode
const negotiationResult = negotiateProtocolVersion(
undefined, // no client version in GET request
undefined, // no client info
req.get('user-agent'),
req.headers
);
logProtocolNegotiation(negotiationResult, logger, 'N8N_MODE_GET');
res.json({
protocolVersion: PROTOCOL_VERSION,
protocolVersion: negotiationResult.version,
serverInfo: {
name: 'n8n-mcp',
version: PROJECT_VERSION,
@@ -800,6 +869,28 @@ export class SingleSessionHTTPServer {
originalUrl: req.originalUrl
});
// Handle connection close to immediately clean up sessions
const sessionId = req.headers['mcp-session-id'] as string | undefined;
// Only add event listener if the request object supports it (not in test mocks)
if (typeof req.on === 'function') {
req.on('close', () => {
if (!res.headersSent && sessionId) {
logger.info('Connection closed before response sent', { sessionId });
// Schedule immediate cleanup if connection closes unexpectedly
setImmediate(() => {
if (this.sessionMetadata[sessionId]) {
const metadata = this.sessionMetadata[sessionId];
const timeSinceAccess = Date.now() - metadata.lastAccess.getTime();
// Only remove if it's been inactive for a bit to avoid race conditions
if (timeSinceAccess > 60000) { // 1 minute
this.removeSession(sessionId, 'connection_closed');
}
}
});
}
});
}
// Enhanced authentication check with specific logging
const authHeader = req.headers.authorization;

View File

@@ -14,6 +14,11 @@ import { isN8nApiConfigured } from './config/n8n-api';
import dotenv from 'dotenv';
import { readFileSync } from 'fs';
import { getStartupBaseUrl, formatEndpointUrls, detectBaseUrl } from './utils/url-detector';
import {
negotiateProtocolVersion,
logProtocolNegotiation,
N8N_PROTOCOL_VERSION
} from './utils/protocol-version';
dotenv.config();
@@ -342,10 +347,20 @@ export async function startFixedHTTPServer() {
switch (jsonRpcRequest.method) {
case 'initialize':
// Negotiate protocol version for this client/request
const negotiationResult = negotiateProtocolVersion(
jsonRpcRequest.params?.protocolVersion,
jsonRpcRequest.params?.clientInfo,
req.get('user-agent'),
req.headers
);
logProtocolNegotiation(negotiationResult, logger, 'HTTP_SERVER_INITIALIZE');
response = {
jsonrpc: '2.0',
result: {
protocolVersion: '2024-11-05',
protocolVersion: negotiationResult.version,
capabilities: {
tools: {},
resources: {}

View File

@@ -9,6 +9,8 @@ import { existsSync, promises as fs } from 'fs';
import path from 'path';
import { n8nDocumentationToolsFinal } from './tools';
import { n8nManagementTools } from './tools-n8n-manager';
import { makeToolsN8nFriendly } from './tools-n8n-friendly';
import { getWorkflowExampleString } from './workflow-examples';
import { logger } from '../utils/logger';
import { NodeRepository } from '../database/node-repository';
import { DatabaseAdapter, createDatabaseAdapter } from '../database/database-adapter';
@@ -26,6 +28,11 @@ import { handleUpdatePartialWorkflow } from './handlers-workflow-diff';
import { getToolDocumentation, getToolsOverview } from './tools-documentation';
import { PROJECT_VERSION } from '../utils/version';
import { normalizeNodeType, getNodeTypeAlternatives, getWorkflowNodeType } from '../utils/node-utils';
import {
negotiateProtocolVersion,
logProtocolNegotiation,
STANDARD_PROTOCOL_VERSION
} from '../utils/protocol-version';
interface NodeRow {
node_type: string;
@@ -52,6 +59,7 @@ export class N8NDocumentationMCPServer {
private templateService: TemplateService | null = null;
private initialized: Promise<void>;
private cache = new SimpleCache();
private clientInfo: any = null;
constructor() {
// Check for test environment first
@@ -154,9 +162,39 @@ export class N8NDocumentationMCPServer {
private setupHandlers(): void {
// Handle initialization
this.server.setRequestHandler(InitializeRequestSchema, async () => {
this.server.setRequestHandler(InitializeRequestSchema, async (request) => {
const clientVersion = request.params.protocolVersion;
const clientCapabilities = request.params.capabilities;
const clientInfo = request.params.clientInfo;
logger.info('MCP Initialize request received', {
clientVersion,
clientCapabilities,
clientInfo
});
// Store client info for later use
this.clientInfo = clientInfo;
// Negotiate protocol version based on client information
const negotiationResult = negotiateProtocolVersion(
clientVersion,
clientInfo,
undefined, // no user agent in MCP protocol
undefined // no headers in MCP protocol
);
logProtocolNegotiation(negotiationResult, logger, 'MCP_INITIALIZE');
// Warn if there's a version mismatch (for debugging)
if (clientVersion && clientVersion !== negotiationResult.version) {
logger.warn(`Protocol version negotiated: client requested ${clientVersion}, server will use ${negotiationResult.version}`, {
reasoning: negotiationResult.reasoning
});
}
const response = {
protocolVersion: '2024-11-05',
protocolVersion: negotiationResult.version,
capabilities: {
tools: {},
},
@@ -166,18 +204,14 @@ export class N8NDocumentationMCPServer {
},
};
// Debug logging
if (process.env.DEBUG_MCP === 'true') {
logger.debug('Initialize handler called', { response });
}
logger.info('MCP Initialize response', { response });
return response;
});
// Handle tool listing
this.server.setRequestHandler(ListToolsRequestSchema, async () => {
this.server.setRequestHandler(ListToolsRequestSchema, async (request) => {
// Combine documentation tools with management tools if API is configured
const tools = [...n8nDocumentationToolsFinal];
let tools = [...n8nDocumentationToolsFinal];
const isConfigured = isN8nApiConfigured();
if (isConfigured) {
@@ -187,6 +221,27 @@ export class N8NDocumentationMCPServer {
logger.debug(`Tool listing: ${tools.length} tools available (documentation only)`);
}
// Check if client is n8n (from initialization)
const clientInfo = this.clientInfo;
const isN8nClient = clientInfo?.name?.includes('n8n') ||
clientInfo?.name?.includes('langchain');
if (isN8nClient) {
logger.info('Detected n8n client, using n8n-friendly tool descriptions');
tools = makeToolsN8nFriendly(tools);
}
// Log validation tools' input schemas for debugging
const validationTools = tools.filter(t => t.name.startsWith('validate_'));
validationTools.forEach(tool => {
logger.info('Validation tool schema', {
toolName: tool.name,
inputSchema: JSON.stringify(tool.inputSchema, null, 2),
hasOutputSchema: !!tool.outputSchema,
description: tool.description
});
});
return { tools };
});
@@ -194,25 +249,124 @@ export class N8NDocumentationMCPServer {
this.server.setRequestHandler(CallToolRequestSchema, async (request) => {
const { name, arguments: args } = request.params;
// Enhanced logging for debugging tool calls
logger.info('Tool call received - DETAILED DEBUG', {
toolName: name,
arguments: JSON.stringify(args, null, 2),
argumentsType: typeof args,
argumentsKeys: args ? Object.keys(args) : [],
hasNodeType: args && 'nodeType' in args,
hasConfig: args && 'config' in args,
configType: args && args.config ? typeof args.config : 'N/A',
rawRequest: JSON.stringify(request.params)
});
// Workaround for n8n's nested output bug
// Check if args contains nested 'output' structure from n8n's memory corruption
let processedArgs = args;
if (args && typeof args === 'object' && 'output' in args) {
try {
logger.debug(`Executing tool: ${name}`, { args });
const result = await this.executeTool(name, args);
const possibleNestedData = args.output;
// If output is a string that looks like JSON, try to parse it
if (typeof possibleNestedData === 'string' && possibleNestedData.trim().startsWith('{')) {
const parsed = JSON.parse(possibleNestedData);
if (parsed && typeof parsed === 'object') {
logger.warn('Detected n8n nested output bug, attempting to extract actual arguments', {
originalArgs: args,
extractedArgs: parsed
});
// Validate the extracted arguments match expected tool schema
if (this.validateExtractedArgs(name, parsed)) {
// Use the extracted data as args
processedArgs = parsed;
} else {
logger.warn('Extracted arguments failed validation, using original args', {
toolName: name,
extractedArgs: parsed
});
}
}
}
} catch (parseError) {
logger.debug('Failed to parse nested output, continuing with original args', {
error: parseError instanceof Error ? parseError.message : String(parseError)
});
}
}
try {
logger.debug(`Executing tool: ${name}`, { args: processedArgs });
const result = await this.executeTool(name, processedArgs);
logger.debug(`Tool ${name} executed successfully`);
return {
// Ensure the result is properly formatted for MCP
let responseText: string;
let structuredContent: any = null;
try {
// For validation tools, check if we should use structured content
if (name.startsWith('validate_') && typeof result === 'object' && result !== null) {
// Clean up the result to ensure it matches the outputSchema
const cleanResult = this.sanitizeValidationResult(result, name);
structuredContent = cleanResult;
responseText = JSON.stringify(cleanResult, null, 2);
} else {
responseText = typeof result === 'string' ? result : JSON.stringify(result, null, 2);
}
} catch (jsonError) {
logger.warn(`Failed to stringify tool result for ${name}:`, jsonError);
responseText = String(result);
}
// Validate response size (n8n might have limits)
if (responseText.length > 1000000) { // 1MB limit
logger.warn(`Tool ${name} response is very large (${responseText.length} chars), truncating`);
responseText = responseText.substring(0, 999000) + '\n\n[Response truncated due to size limits]';
structuredContent = null; // Don't use structured content for truncated responses
}
// Build MCP response with strict schema compliance
const mcpResponse: any = {
content: [
{
type: 'text',
text: JSON.stringify(result, null, 2),
type: 'text' as const,
text: responseText,
},
],
};
// For tools with outputSchema, structuredContent is REQUIRED by MCP spec
if (name.startsWith('validate_') && structuredContent !== null) {
mcpResponse.structuredContent = structuredContent;
}
return mcpResponse;
} catch (error) {
logger.error(`Error executing tool ${name}`, error);
const errorMessage = error instanceof Error ? error.message : 'Unknown error';
// Provide more helpful error messages for common n8n issues
let helpfulMessage = `Error executing tool ${name}: ${errorMessage}`;
if (errorMessage.includes('required') || errorMessage.includes('missing')) {
helpfulMessage += '\n\nNote: This error often occurs when the AI agent sends incomplete or incorrectly formatted parameters. Please ensure all required fields are provided with the correct types.';
} else if (errorMessage.includes('type') || errorMessage.includes('expected')) {
helpfulMessage += '\n\nNote: This error indicates a type mismatch. The AI agent may be sending data in the wrong format (e.g., string instead of object).';
} else if (errorMessage.includes('Unknown category') || errorMessage.includes('not found')) {
helpfulMessage += '\n\nNote: The requested resource or category was not found. Please check the available options.';
}
// For n8n schema errors, add specific guidance
if (name.startsWith('validate_') && (errorMessage.includes('config') || errorMessage.includes('nodeType'))) {
helpfulMessage += '\n\nFor validation tools:\n- nodeType should be a string (e.g., "nodes-base.webhook")\n- config should be an object (e.g., {})';
}
return {
content: [
{
type: 'text',
text: `Error executing tool ${name}: ${error instanceof Error ? error.message : 'Unknown error'}`,
text: helpfulMessage,
},
],
isError: true,
@@ -221,6 +375,90 @@ export class N8NDocumentationMCPServer {
});
}
/**
* Sanitize validation result to match outputSchema
*/
private sanitizeValidationResult(result: any, toolName: string): any {
if (!result || typeof result !== 'object') {
return result;
}
const sanitized = { ...result };
// Ensure required fields exist with proper types and filter to schema-defined fields only
if (toolName === 'validate_node_minimal') {
// Filter to only schema-defined fields
const filtered = {
nodeType: String(sanitized.nodeType || ''),
displayName: String(sanitized.displayName || ''),
valid: Boolean(sanitized.valid),
missingRequiredFields: Array.isArray(sanitized.missingRequiredFields)
? sanitized.missingRequiredFields.map(String)
: []
};
return filtered;
} else if (toolName === 'validate_node_operation') {
// Ensure summary exists
let summary = sanitized.summary;
if (!summary || typeof summary !== 'object') {
summary = {
hasErrors: Array.isArray(sanitized.errors) ? sanitized.errors.length > 0 : false,
errorCount: Array.isArray(sanitized.errors) ? sanitized.errors.length : 0,
warningCount: Array.isArray(sanitized.warnings) ? sanitized.warnings.length : 0,
suggestionCount: Array.isArray(sanitized.suggestions) ? sanitized.suggestions.length : 0
};
}
// Filter to only schema-defined fields
const filtered = {
nodeType: String(sanitized.nodeType || ''),
workflowNodeType: String(sanitized.workflowNodeType || sanitized.nodeType || ''),
displayName: String(sanitized.displayName || ''),
valid: Boolean(sanitized.valid),
errors: Array.isArray(sanitized.errors) ? sanitized.errors : [],
warnings: Array.isArray(sanitized.warnings) ? sanitized.warnings : [],
suggestions: Array.isArray(sanitized.suggestions) ? sanitized.suggestions : [],
summary: summary
};
return filtered;
} else if (toolName.startsWith('validate_workflow')) {
sanitized.valid = Boolean(sanitized.valid);
// Ensure arrays exist
sanitized.errors = Array.isArray(sanitized.errors) ? sanitized.errors : [];
sanitized.warnings = Array.isArray(sanitized.warnings) ? sanitized.warnings : [];
// Ensure statistics/summary exists
if (toolName === 'validate_workflow') {
if (!sanitized.summary || typeof sanitized.summary !== 'object') {
sanitized.summary = {
totalNodes: 0,
enabledNodes: 0,
triggerNodes: 0,
validConnections: 0,
invalidConnections: 0,
expressionsValidated: 0,
errorCount: sanitized.errors.length,
warningCount: sanitized.warnings.length
};
}
} else {
if (!sanitized.statistics || typeof sanitized.statistics !== 'object') {
sanitized.statistics = {
totalNodes: 0,
triggerNodes: 0,
validConnections: 0,
invalidConnections: 0,
expressionsValidated: 0
};
}
}
}
// Remove undefined values to ensure clean JSON
return JSON.parse(JSON.stringify(sanitized));
}
/**
* Validate required parameters for tool execution
*/
@@ -238,10 +476,95 @@ export class N8NDocumentationMCPServer {
}
}
/**
* Validate extracted arguments match expected tool schema
*/
private validateExtractedArgs(toolName: string, args: any): boolean {
if (!args || typeof args !== 'object') {
return false;
}
// Get all available tools
const allTools = [...n8nDocumentationToolsFinal, ...n8nManagementTools];
const tool = allTools.find(t => t.name === toolName);
if (!tool || !tool.inputSchema) {
return true; // If no schema, assume valid
}
const schema = tool.inputSchema;
const required = schema.required || [];
const properties = schema.properties || {};
// Check all required fields are present
for (const requiredField of required) {
if (!(requiredField in args)) {
logger.debug(`Extracted args missing required field: ${requiredField}`, {
toolName,
extractedArgs: args,
required
});
return false;
}
}
// Check field types match schema
for (const [fieldName, fieldValue] of Object.entries(args)) {
if (properties[fieldName]) {
const expectedType = properties[fieldName].type;
const actualType = Array.isArray(fieldValue) ? 'array' : typeof fieldValue;
// Basic type validation
if (expectedType && expectedType !== actualType) {
// Special case: number can be coerced from string
if (expectedType === 'number' && actualType === 'string' && !isNaN(Number(fieldValue))) {
continue;
}
logger.debug(`Extracted args field type mismatch: ${fieldName}`, {
toolName,
expectedType,
actualType,
fieldValue
});
return false;
}
}
}
// Check for extraneous fields if additionalProperties is false
if (schema.additionalProperties === false) {
const allowedFields = Object.keys(properties);
const extraFields = Object.keys(args).filter(field => !allowedFields.includes(field));
if (extraFields.length > 0) {
logger.debug(`Extracted args have extra fields`, {
toolName,
extraFields,
allowedFields
});
// For n8n compatibility, we'll still consider this valid but log it
}
}
return true;
}
async executeTool(name: string, args: any): Promise<any> {
// Ensure args is an object
// Ensure args is an object and validate it
args = args || {};
// Log the tool call for debugging n8n issues
logger.info(`Tool execution: ${name}`, {
args: typeof args === 'object' ? JSON.stringify(args) : args,
argsType: typeof args,
argsKeys: typeof args === 'object' ? Object.keys(args) : 'not-object'
});
// Validate that args is actually an object
if (typeof args !== 'object' || args === null) {
throw new Error(`Invalid arguments for tool ${name}: expected object, got ${typeof args}`);
}
switch (name) {
case 'tools_documentation':
// No required parameters
@@ -281,9 +604,43 @@ export class N8NDocumentationMCPServer {
return this.listTasks(args.category);
case 'validate_node_operation':
this.validateToolParams(name, args, ['nodeType', 'config']);
// Ensure config is an object
if (typeof args.config !== 'object' || args.config === null) {
logger.warn(`validate_node_operation called with invalid config type: ${typeof args.config}`);
return {
nodeType: args.nodeType || 'unknown',
workflowNodeType: args.nodeType || 'unknown',
displayName: 'Unknown Node',
valid: false,
errors: [{
type: 'config',
property: 'config',
message: 'Invalid config format - expected object',
fix: 'Provide config as an object with node properties'
}],
warnings: [],
suggestions: [],
summary: {
hasErrors: true,
errorCount: 1,
warningCount: 0,
suggestionCount: 0
}
};
}
return this.validateNodeConfig(args.nodeType, args.config, 'operation', args.profile);
case 'validate_node_minimal':
this.validateToolParams(name, args, ['nodeType', 'config']);
// Ensure config is an object
if (typeof args.config !== 'object' || args.config === null) {
logger.warn(`validate_node_minimal called with invalid config type: ${typeof args.config}`);
return {
nodeType: args.nodeType || 'unknown',
displayName: 'Unknown Node',
valid: false,
missingRequiredFields: ['Invalid config format - expected object']
};
}
return this.validateNodeMinimal(args.nodeType, args.config);
case 'get_property_dependencies':
this.validateToolParams(name, args, ['nodeType']);
@@ -1909,6 +2266,56 @@ Full documentation is being prepared. For now, use get_node_essentials for confi
await this.ensureInitialized();
if (!this.repository) throw new Error('Repository not initialized');
// Enhanced logging for workflow validation
logger.info('Workflow validation requested', {
hasWorkflow: !!workflow,
workflowType: typeof workflow,
hasNodes: workflow?.nodes !== undefined,
nodesType: workflow?.nodes ? typeof workflow.nodes : 'undefined',
nodesIsArray: Array.isArray(workflow?.nodes),
nodesCount: Array.isArray(workflow?.nodes) ? workflow.nodes.length : 0,
hasConnections: workflow?.connections !== undefined,
connectionsType: workflow?.connections ? typeof workflow.connections : 'undefined',
options: options
});
// Help n8n AI agents with common mistakes
if (!workflow || typeof workflow !== 'object') {
return {
valid: false,
errors: [{
node: 'workflow',
message: 'Workflow must be an object with nodes and connections',
details: 'Expected format: ' + getWorkflowExampleString()
}],
summary: { errorCount: 1 }
};
}
if (!workflow.nodes || !Array.isArray(workflow.nodes)) {
return {
valid: false,
errors: [{
node: 'workflow',
message: 'Workflow must have a nodes array',
details: 'Expected: workflow.nodes = [array of node objects]. ' + getWorkflowExampleString()
}],
summary: { errorCount: 1 }
};
}
if (!workflow.connections || typeof workflow.connections !== 'object') {
return {
valid: false,
errors: [{
node: 'workflow',
message: 'Workflow must have a connections object',
details: 'Expected: workflow.connections = {} (can be empty object). ' + getWorkflowExampleString()
}],
summary: { errorCount: 1 }
};
}
// Create workflow validator instance
const validator = new WorkflowValidator(
this.repository,

View File

@@ -0,0 +1,175 @@
/**
* n8n-friendly tool descriptions
* These descriptions are optimized to reduce schema validation errors in n8n's AI Agent
*
* Key principles:
* 1. Use exact JSON examples in descriptions
* 2. Be explicit about data types
* 3. Keep descriptions short and directive
* 4. Avoid ambiguity
*/
export const n8nFriendlyDescriptions: Record<string, {
description: string;
params: Record<string, string>;
}> = {
// Validation tools - most prone to errors
validate_node_operation: {
description: 'Validate n8n node. ALWAYS pass two parameters: nodeType (string) and config (object). Example call: {"nodeType": "nodes-base.slack", "config": {"resource": "channel", "operation": "create"}}',
params: {
nodeType: 'String value like "nodes-base.slack"',
config: 'Object value like {"resource": "channel", "operation": "create"} or empty object {}',
profile: 'Optional string: "minimal" or "runtime" or "ai-friendly" or "strict"'
}
},
validate_node_minimal: {
description: 'Check required fields. MUST pass: nodeType (string) and config (object). Example: {"nodeType": "nodes-base.webhook", "config": {}}',
params: {
nodeType: 'String like "nodes-base.webhook"',
config: 'Object, use {} for empty'
}
},
// Search and info tools
search_nodes: {
description: 'Search nodes. Pass query (string). Example: {"query": "webhook"}',
params: {
query: 'String keyword like "webhook" or "database"',
limit: 'Optional number, default 20'
}
},
get_node_info: {
description: 'Get node details. Pass nodeType (string). Example: {"nodeType": "nodes-base.httpRequest"}',
params: {
nodeType: 'String with prefix like "nodes-base.httpRequest"'
}
},
get_node_essentials: {
description: 'Get node basics. Pass nodeType (string). Example: {"nodeType": "nodes-base.slack"}',
params: {
nodeType: 'String with prefix like "nodes-base.slack"'
}
},
// Task tools
get_node_for_task: {
description: 'Find node for task. Pass task (string). Example: {"task": "send_http_request"}',
params: {
task: 'String task name like "send_http_request"'
}
},
list_tasks: {
description: 'List tasks by category. Pass category (string). Example: {"category": "HTTP/API"}',
params: {
category: 'String: "HTTP/API" or "Webhooks" or "Database" or "AI/LangChain" or "Data Processing" or "Communication"'
}
},
// Workflow validation
validate_workflow: {
description: 'Validate workflow. Pass workflow object. MUST have: {"workflow": {"nodes": [array of node objects], "connections": {object with node connections}}}. Each node needs: name, type, typeVersion, position.',
params: {
workflow: 'Object with two required fields: nodes (array) and connections (object). Example: {"nodes": [{"name": "Webhook", "type": "n8n-nodes-base.webhook", "typeVersion": 2, "position": [250, 300], "parameters": {}}], "connections": {}}',
options: 'Optional object. Example: {"validateNodes": true, "profile": "runtime"}'
}
},
validate_workflow_connections: {
description: 'Validate workflow connections only. Pass workflow object. Example: {"workflow": {"nodes": [...], "connections": {}}}',
params: {
workflow: 'Object with nodes array and connections object. Minimal example: {"nodes": [{"name": "Webhook"}], "connections": {}}'
}
},
validate_workflow_expressions: {
description: 'Validate n8n expressions in workflow. Pass workflow object. Example: {"workflow": {"nodes": [...], "connections": {}}}',
params: {
workflow: 'Object with nodes array and connections object containing n8n expressions like {{ $json.data }}'
}
},
// Property tools
get_property_dependencies: {
description: 'Get field dependencies. Pass nodeType (string) and optional config (object). Example: {"nodeType": "nodes-base.httpRequest", "config": {}}',
params: {
nodeType: 'String like "nodes-base.httpRequest"',
config: 'Optional object, use {} for empty'
}
},
// AI tool info
get_node_as_tool_info: {
description: 'Get AI tool usage. Pass nodeType (string). Example: {"nodeType": "nodes-base.slack"}',
params: {
nodeType: 'String with prefix like "nodes-base.slack"'
}
},
// Template tools
search_templates: {
description: 'Search workflow templates. Pass query (string). Example: {"query": "chatbot"}',
params: {
query: 'String keyword like "chatbot" or "webhook"',
limit: 'Optional number, default 20'
}
},
get_template: {
description: 'Get template by ID. Pass templateId (number). Example: {"templateId": 1234}',
params: {
templateId: 'Number ID like 1234'
}
},
// Documentation tool
tools_documentation: {
description: 'Get tool docs. Pass optional depth (string). Example: {"depth": "essentials"} or {}',
params: {
depth: 'Optional string: "essentials" or "overview" or "detailed"',
topic: 'Optional string topic name'
}
}
};
/**
* Apply n8n-friendly descriptions to tools
* This function modifies tool descriptions to be more explicit for n8n's AI agent
*/
export function makeToolsN8nFriendly(tools: any[]): any[] {
return tools.map(tool => {
const toolName = tool.name as string;
const friendlyDesc = n8nFriendlyDescriptions[toolName];
if (friendlyDesc) {
// Clone the tool to avoid mutating the original
const updatedTool = { ...tool };
// Update the main description
updatedTool.description = friendlyDesc.description;
// Clone inputSchema if it exists
if (tool.inputSchema?.properties) {
updatedTool.inputSchema = {
...tool.inputSchema,
properties: { ...tool.inputSchema.properties }
};
// Update parameter descriptions
Object.keys(updatedTool.inputSchema.properties).forEach(param => {
if (friendlyDesc.params[param]) {
updatedTool.inputSchema.properties[param] = {
...updatedTool.inputSchema.properties[param],
description: friendlyDesc.params[param]
};
}
});
}
return updatedTool;
}
return tool;
});
}

View File

@@ -59,7 +59,7 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
{
name: 'get_node_info',
description: `Get FULL node schema (100KB+). TIP: Use get_node_essentials first! Returns all properties/operations/credentials. Prefix required: "nodes-base.httpRequest" not "httpRequest".`,
description: `Get full node documentation. Pass nodeType as string with prefix. Example: nodeType="nodes-base.webhook"`,
inputSchema: {
type: 'object',
properties: {
@@ -73,7 +73,7 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
{
name: 'search_nodes',
description: `Search nodes by keywords. Modes: OR (any word), AND (all words), FUZZY (typos OK). Primary nodes ranked first. Examples: "webhook"→Webhook, "http call"→HTTP Request.`,
description: `Search n8n nodes by keyword. Pass query as string. Example: query="webhook" or query="database". Returns max 20 results.`,
inputSchema: {
type: 'object',
properties: {
@@ -128,7 +128,7 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
{
name: 'get_node_essentials',
description: `Get 10-20 key properties only (<5KB vs 100KB+). USE THIS FIRST! Includes examples. Format: "nodes-base.httpRequest"`,
description: `Get node essential info. Pass nodeType as string with prefix. Example: nodeType="nodes-base.slack"`,
inputSchema: {
type: 'object',
properties: {
@@ -192,44 +192,103 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
{
name: 'validate_node_operation',
description: `Validate node config. Checks required fields, types, operation rules. Returns errors with fixes. Essential for Slack/Sheets/DB nodes.`,
description: `Validate n8n node configuration. Pass nodeType as string and config as object. Example: nodeType="nodes-base.slack", config={resource:"channel",operation:"create"}`,
inputSchema: {
type: 'object',
properties: {
nodeType: {
type: 'string',
description: 'The node type to validate (e.g., "nodes-base.slack")',
description: 'Node type as string. Example: "nodes-base.slack"',
},
config: {
type: 'object',
description: 'Your node configuration. Must include operation fields (resource/operation/action) if the node has multiple operations.',
description: 'Configuration as object. For simple nodes use {}. For complex nodes include fields like {resource:"channel",operation:"create"}',
},
profile: {
type: 'string',
enum: ['strict', 'runtime', 'ai-friendly', 'minimal'],
description: 'Validation profile: minimal (only required fields), runtime (critical errors only), ai-friendly (balanced - default), strict (all checks including best practices)',
description: 'Profile string: "minimal", "runtime", "ai-friendly", or "strict". Default is "ai-friendly"',
default: 'ai-friendly',
},
},
required: ['nodeType', 'config'],
additionalProperties: false,
},
outputSchema: {
type: 'object',
properties: {
nodeType: { type: 'string' },
workflowNodeType: { type: 'string' },
displayName: { type: 'string' },
valid: { type: 'boolean' },
errors: {
type: 'array',
items: {
type: 'object',
properties: {
type: { type: 'string' },
property: { type: 'string' },
message: { type: 'string' },
fix: { type: 'string' }
}
}
},
warnings: {
type: 'array',
items: {
type: 'object',
properties: {
type: { type: 'string' },
property: { type: 'string' },
message: { type: 'string' },
suggestion: { type: 'string' }
}
}
},
suggestions: { type: 'array', items: { type: 'string' } },
summary: {
type: 'object',
properties: {
hasErrors: { type: 'boolean' },
errorCount: { type: 'number' },
warningCount: { type: 'number' },
suggestionCount: { type: 'number' }
}
}
},
required: ['nodeType', 'displayName', 'valid', 'errors', 'warnings', 'suggestions', 'summary']
},
},
{
name: 'validate_node_minimal',
description: `Fast check for missing required fields only. No warnings/suggestions. Returns: list of missing fields.`,
description: `Check n8n node required fields. Pass nodeType as string and config as empty object {}. Example: nodeType="nodes-base.webhook", config={}`,
inputSchema: {
type: 'object',
properties: {
nodeType: {
type: 'string',
description: 'The node type to validate (e.g., "nodes-base.slack")',
description: 'Node type as string. Example: "nodes-base.slack"',
},
config: {
type: 'object',
description: 'The node configuration to check',
description: 'Configuration object. Always pass {} for empty config',
},
},
required: ['nodeType', 'config'],
additionalProperties: false,
},
outputSchema: {
type: 'object',
properties: {
nodeType: { type: 'string' },
displayName: { type: 'string' },
valid: { type: 'boolean' },
missingRequiredFields: {
type: 'array',
items: { type: 'string' }
}
},
required: ['nodeType', 'displayName', 'valid', 'missingRequiredFields']
},
},
{
@@ -306,7 +365,7 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
properties: {
query: {
type: 'string',
description: 'Search query for template names/descriptions. NOT for node types! Examples: "chatbot", "automation", "social media", "webhook". For node-based search use list_node_templates instead.',
description: 'Search keyword as string. Example: "chatbot"',
},
limit: {
type: 'number',
@@ -382,6 +441,50 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
},
required: ['workflow'],
additionalProperties: false,
},
outputSchema: {
type: 'object',
properties: {
valid: { type: 'boolean' },
summary: {
type: 'object',
properties: {
totalNodes: { type: 'number' },
enabledNodes: { type: 'number' },
triggerNodes: { type: 'number' },
validConnections: { type: 'number' },
invalidConnections: { type: 'number' },
expressionsValidated: { type: 'number' },
errorCount: { type: 'number' },
warningCount: { type: 'number' }
}
},
errors: {
type: 'array',
items: {
type: 'object',
properties: {
node: { type: 'string' },
message: { type: 'string' },
details: { type: 'string' }
}
}
},
warnings: {
type: 'array',
items: {
type: 'object',
properties: {
node: { type: 'string' },
message: { type: 'string' },
details: { type: 'string' }
}
}
},
suggestions: { type: 'array', items: { type: 'string' } }
},
required: ['valid', 'summary']
},
},
{
@@ -396,6 +499,43 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
},
required: ['workflow'],
additionalProperties: false,
},
outputSchema: {
type: 'object',
properties: {
valid: { type: 'boolean' },
statistics: {
type: 'object',
properties: {
totalNodes: { type: 'number' },
triggerNodes: { type: 'number' },
validConnections: { type: 'number' },
invalidConnections: { type: 'number' }
}
},
errors: {
type: 'array',
items: {
type: 'object',
properties: {
node: { type: 'string' },
message: { type: 'string' }
}
}
},
warnings: {
type: 'array',
items: {
type: 'object',
properties: {
node: { type: 'string' },
message: { type: 'string' }
}
}
}
},
required: ['valid', 'statistics']
},
},
{
@@ -410,6 +550,42 @@ export const n8nDocumentationToolsFinal: ToolDefinition[] = [
},
},
required: ['workflow'],
additionalProperties: false,
},
outputSchema: {
type: 'object',
properties: {
valid: { type: 'boolean' },
statistics: {
type: 'object',
properties: {
totalNodes: { type: 'number' },
expressionsValidated: { type: 'number' }
}
},
errors: {
type: 'array',
items: {
type: 'object',
properties: {
node: { type: 'string' },
message: { type: 'string' }
}
}
},
warnings: {
type: 'array',
items: {
type: 'object',
properties: {
node: { type: 'string' },
message: { type: 'string' }
}
}
},
tips: { type: 'array', items: { type: 'string' } }
},
required: ['valid', 'statistics']
},
},
];

View File

@@ -0,0 +1,112 @@
/**
* Example workflows for n8n AI agents to understand the structure
*/
export const MINIMAL_WORKFLOW_EXAMPLE = {
nodes: [
{
name: "Webhook",
type: "n8n-nodes-base.webhook",
typeVersion: 2,
position: [250, 300],
parameters: {
httpMethod: "POST",
path: "webhook"
}
}
],
connections: {}
};
export const SIMPLE_WORKFLOW_EXAMPLE = {
nodes: [
{
name: "Webhook",
type: "n8n-nodes-base.webhook",
typeVersion: 2,
position: [250, 300],
parameters: {
httpMethod: "POST",
path: "webhook"
}
},
{
name: "Set",
type: "n8n-nodes-base.set",
typeVersion: 2,
position: [450, 300],
parameters: {
mode: "manual",
assignments: {
assignments: [
{
name: "message",
type: "string",
value: "Hello"
}
]
}
}
},
{
name: "Respond to Webhook",
type: "n8n-nodes-base.respondToWebhook",
typeVersion: 1,
position: [650, 300],
parameters: {
respondWith: "firstIncomingItem"
}
}
],
connections: {
"Webhook": {
"main": [
[
{
"node": "Set",
"type": "main",
"index": 0
}
]
]
},
"Set": {
"main": [
[
{
"node": "Respond to Webhook",
"type": "main",
"index": 0
}
]
]
}
}
};
export function getWorkflowExampleString(): string {
return `Example workflow structure:
${JSON.stringify(MINIMAL_WORKFLOW_EXAMPLE, null, 2)}
Each node MUST have:
- name: unique string identifier
- type: full node type with prefix (e.g., "n8n-nodes-base.webhook")
- typeVersion: number (usually 1 or 2)
- position: [x, y] coordinates array
- parameters: object with node-specific settings
Connections format:
{
"SourceNodeName": {
"main": [
[
{
"node": "TargetNodeName",
"type": "main",
"index": 0
}
]
]
}
}`;
}

View File

@@ -0,0 +1,206 @@
#!/usr/bin/env node
/**
* Test Protocol Version Negotiation
*
* This script tests the protocol version negotiation logic with different client scenarios.
*/
import {
negotiateProtocolVersion,
isN8nClient,
STANDARD_PROTOCOL_VERSION,
N8N_PROTOCOL_VERSION
} from '../utils/protocol-version';
interface TestCase {
name: string;
clientVersion?: string;
clientInfo?: any;
userAgent?: string;
headers?: Record<string, string>;
expectedVersion: string;
expectedIsN8nClient: boolean;
}
const testCases: TestCase[] = [
{
name: 'Standard MCP client (Claude Desktop)',
clientVersion: '2025-03-26',
clientInfo: { name: 'Claude Desktop', version: '1.0.0' },
expectedVersion: '2025-03-26',
expectedIsN8nClient: false
},
{
name: 'n8n client with specific client info',
clientVersion: '2025-03-26',
clientInfo: { name: 'n8n', version: '1.0.0' },
expectedVersion: N8N_PROTOCOL_VERSION,
expectedIsN8nClient: true
},
{
name: 'LangChain client',
clientVersion: '2025-03-26',
clientInfo: { name: 'langchain-js', version: '0.1.0' },
expectedVersion: N8N_PROTOCOL_VERSION,
expectedIsN8nClient: true
},
{
name: 'n8n client via user agent',
clientVersion: '2025-03-26',
userAgent: 'n8n/1.0.0',
expectedVersion: N8N_PROTOCOL_VERSION,
expectedIsN8nClient: true
},
{
name: 'n8n mode environment variable',
clientVersion: '2025-03-26',
expectedVersion: N8N_PROTOCOL_VERSION,
expectedIsN8nClient: true
},
{
name: 'Client requesting older version',
clientVersion: '2024-06-25',
clientInfo: { name: 'Some Client', version: '1.0.0' },
expectedVersion: '2024-06-25',
expectedIsN8nClient: false
},
{
name: 'Client requesting unsupported version',
clientVersion: '2020-01-01',
clientInfo: { name: 'Old Client', version: '1.0.0' },
expectedVersion: STANDARD_PROTOCOL_VERSION,
expectedIsN8nClient: false
},
{
name: 'No client info provided',
expectedVersion: STANDARD_PROTOCOL_VERSION,
expectedIsN8nClient: false
},
{
name: 'n8n headers detection',
clientVersion: '2025-03-26',
headers: { 'x-n8n-version': '1.0.0' },
expectedVersion: N8N_PROTOCOL_VERSION,
expectedIsN8nClient: true
}
];
async function runTests(): Promise<void> {
console.log('🧪 Testing Protocol Version Negotiation\n');
let passed = 0;
let failed = 0;
// Set N8N_MODE for the environment variable test
const originalN8nMode = process.env.N8N_MODE;
for (const testCase of testCases) {
try {
// Set N8N_MODE for specific test
if (testCase.name.includes('environment variable')) {
process.env.N8N_MODE = 'true';
} else {
delete process.env.N8N_MODE;
}
// Test isN8nClient function
const detectedAsN8n = isN8nClient(testCase.clientInfo, testCase.userAgent, testCase.headers);
// Test negotiateProtocolVersion function
const result = negotiateProtocolVersion(
testCase.clientVersion,
testCase.clientInfo,
testCase.userAgent,
testCase.headers
);
// Check results
const versionCorrect = result.version === testCase.expectedVersion;
const n8nDetectionCorrect = result.isN8nClient === testCase.expectedIsN8nClient;
const isN8nFunctionCorrect = detectedAsN8n === testCase.expectedIsN8nClient;
if (versionCorrect && n8nDetectionCorrect && isN8nFunctionCorrect) {
console.log(`${testCase.name}`);
console.log(` Version: ${result.version}, n8n client: ${result.isN8nClient}`);
console.log(` Reasoning: ${result.reasoning}\n`);
passed++;
} else {
console.log(`${testCase.name}`);
console.log(` Expected: version=${testCase.expectedVersion}, isN8n=${testCase.expectedIsN8nClient}`);
console.log(` Got: version=${result.version}, isN8n=${result.isN8nClient}`);
console.log(` isN8nClient function: ${detectedAsN8n} (expected: ${testCase.expectedIsN8nClient})`);
console.log(` Reasoning: ${result.reasoning}\n`);
failed++;
}
} catch (error) {
console.log(`💥 ${testCase.name} - ERROR`);
console.log(` ${error instanceof Error ? error.message : String(error)}\n`);
failed++;
}
}
// Restore original N8N_MODE
if (originalN8nMode) {
process.env.N8N_MODE = originalN8nMode;
} else {
delete process.env.N8N_MODE;
}
// Summary
console.log(`\n📊 Test Results:`);
console.log(` ✅ Passed: ${passed}`);
console.log(` ❌ Failed: ${failed}`);
console.log(` Total: ${passed + failed}`);
if (failed > 0) {
console.log(`\n❌ Some tests failed!`);
process.exit(1);
} else {
console.log(`\n🎉 All tests passed!`);
}
}
// Additional integration test
async function testIntegration(): Promise<void> {
console.log('\n🔧 Integration Test - MCP Server Protocol Negotiation\n');
// This would normally test the actual MCP server, but we'll just verify
// the negotiation logic works in typical scenarios
const scenarios = [
{
name: 'Claude Desktop connecting',
clientInfo: { name: 'Claude Desktop', version: '1.0.0' },
clientVersion: '2025-03-26'
},
{
name: 'n8n connecting via HTTP',
headers: { 'user-agent': 'n8n/1.52.0' },
clientVersion: '2025-03-26'
}
];
for (const scenario of scenarios) {
const result = negotiateProtocolVersion(
scenario.clientVersion,
scenario.clientInfo,
scenario.headers?.['user-agent'],
scenario.headers
);
console.log(`🔍 ${scenario.name}:`);
console.log(` Negotiated version: ${result.version}`);
console.log(` Is n8n client: ${result.isN8nClient}`);
console.log(` Reasoning: ${result.reasoning}\n`);
}
}
if (require.main === module) {
runTests()
.then(() => testIntegration())
.catch(error => {
console.error('Test execution failed:', error);
process.exit(1);
});
}

View File

@@ -13,6 +13,12 @@ export interface ToolDefinition {
required?: string[];
additionalProperties?: boolean | Record<string, any>;
};
outputSchema?: {
type: string;
properties: Record<string, any>;
required?: string[];
additionalProperties?: boolean | Record<string, any>;
};
}
export interface ResourceDefinition {

View File

@@ -0,0 +1,175 @@
/**
* Protocol Version Negotiation Utility
*
* Handles MCP protocol version negotiation between server and clients,
* with special handling for n8n clients that require specific versions.
*/
export interface ClientInfo {
name?: string;
version?: string;
[key: string]: any;
}
export interface ProtocolNegotiationResult {
version: string;
isN8nClient: boolean;
reasoning: string;
}
/**
* Standard MCP protocol version (latest)
*/
export const STANDARD_PROTOCOL_VERSION = '2025-03-26';
/**
* n8n specific protocol version (what n8n expects)
*/
export const N8N_PROTOCOL_VERSION = '2024-11-05';
/**
* Supported protocol versions in order of preference
*/
export const SUPPORTED_VERSIONS = [
STANDARD_PROTOCOL_VERSION,
N8N_PROTOCOL_VERSION,
'2024-06-25', // Older fallback
];
/**
* Detect if the client is n8n based on various indicators
*/
export function isN8nClient(
clientInfo?: ClientInfo,
userAgent?: string,
headers?: Record<string, string | string[] | undefined>
): boolean {
// Check client info
if (clientInfo?.name) {
const clientName = clientInfo.name.toLowerCase();
if (clientName.includes('n8n') || clientName.includes('langchain')) {
return true;
}
}
// Check user agent
if (userAgent) {
const ua = userAgent.toLowerCase();
if (ua.includes('n8n') || ua.includes('langchain')) {
return true;
}
}
// Check headers for n8n-specific indicators
if (headers) {
// Check for n8n-specific headers or values
const headerValues = Object.values(headers).join(' ').toLowerCase();
if (headerValues.includes('n8n') || headerValues.includes('langchain')) {
return true;
}
// Check specific header patterns that n8n might use
if (headers['x-n8n-version'] || headers['x-langchain-version']) {
return true;
}
}
// Check environment variable that might indicate n8n mode
if (process.env.N8N_MODE === 'true') {
return true;
}
return false;
}
/**
* Negotiate protocol version based on client information
*/
export function negotiateProtocolVersion(
clientRequestedVersion?: string,
clientInfo?: ClientInfo,
userAgent?: string,
headers?: Record<string, string | string[] | undefined>
): ProtocolNegotiationResult {
const isN8n = isN8nClient(clientInfo, userAgent, headers);
// For n8n clients, always use the n8n-specific version
if (isN8n) {
return {
version: N8N_PROTOCOL_VERSION,
isN8nClient: true,
reasoning: 'n8n client detected, using n8n-compatible protocol version'
};
}
// If client requested a specific version, try to honor it if supported
if (clientRequestedVersion && SUPPORTED_VERSIONS.includes(clientRequestedVersion)) {
return {
version: clientRequestedVersion,
isN8nClient: false,
reasoning: `Using client-requested version: ${clientRequestedVersion}`
};
}
// If client requested an unsupported version, use the closest supported one
if (clientRequestedVersion) {
// For now, default to standard version for unknown requests
return {
version: STANDARD_PROTOCOL_VERSION,
isN8nClient: false,
reasoning: `Client requested unsupported version ${clientRequestedVersion}, using standard version`
};
}
// Default to standard protocol version for unknown clients
return {
version: STANDARD_PROTOCOL_VERSION,
isN8nClient: false,
reasoning: 'No specific client detected, using standard protocol version'
};
}
/**
* Check if a protocol version is supported
*/
export function isVersionSupported(version: string): boolean {
return SUPPORTED_VERSIONS.includes(version);
}
/**
* Get the most appropriate protocol version for backwards compatibility
* This is used when we need to maintain compatibility with older clients
*/
export function getCompatibleVersion(targetVersion?: string): string {
if (!targetVersion) {
return STANDARD_PROTOCOL_VERSION;
}
if (SUPPORTED_VERSIONS.includes(targetVersion)) {
return targetVersion;
}
// If not supported, return the most recent supported version
return STANDARD_PROTOCOL_VERSION;
}
/**
* Log protocol version negotiation for debugging
*/
export function logProtocolNegotiation(
result: ProtocolNegotiationResult,
logger: any,
context?: string
): void {
const logContext = context ? `[${context}] ` : '';
logger.info(`${logContext}Protocol version negotiated`, {
version: result.version,
isN8nClient: result.isN8nClient,
reasoning: result.reasoning
});
if (result.isN8nClient) {
logger.info(`${logContext}Using n8n-compatible protocol version for better integration`);
}
}