salacoste

Comprehensive MCP Server Fixes for n8n Workflow Builder

Productivity community intermediate

SOURCE https://github.com/salacoste/mcp-n8n-workflow-builder

Description

Comprehensive MCP Server Fixes for n8n Workflow Builder skill

Installation

This entry records only its repository, not the path inside it, so there is no exact command to give. Open the source below and copy the folder into ~/.claude/skills/, or the file into ~/.claude/agents/.

Repository README

This is the README for salacoste/mcp-n8n-workflow-builder, shared by 8 entries in this directory. It describes the repository, not this entry specifically.

Comprehensive MCP Server Fixes for n8n Workflow Builder

Overview

This PR contains comprehensive fixes for critical bugs in the MCP (Model Context Protocol) server that were preventing proper functionality with n8n workflow automation.

Critical Bug Fixes

1. Transport Mode Detection Issue

Problem: Server was trying to use both stdin/stdout transport and HTTP server simultaneously, causing conflicts
Fix: Added smart detection between standalone HTTP mode vs MCP subprocess mode using process.env.MCP_STANDALONE and process.stdin.isTTY
Files: src/index.ts

2. Workflow Listing Bug

Problem: workflows.filter is not a function error due to incorrect API response parsing
Fix: Corrected workflow array extraction from n8n API response structure {data: [], nextCursor: null}
Files: src/services/n8nApiWrapper.ts

3. API Base URL Configuration

Problem: Missing /api/v1 path in n8n API calls
Fix: Updated API base URL to include proper /api/v1 path (${envConfig.n8n_host}/api/v1)
Files: src/services/environmentManager.ts

Workflow Execution Research & Documentation

4. Workflow Execution Limitation Discovery

Research: Extensive analysis of successful executions revealed that Manual Trigger workflows are executed through n8n's web interface, not REST API
Evidence: Found successful executions with "mode": "manual" that occurred via web interface
Documentation: Added comprehensive guidance about execution limitations and alternatives
Files: src/services/n8nApiWrapper.ts

5. Improved User Experience

Enhancement: Replaced failed API attempts with helpful guidance
Features:
- Clear explanation of n8n design limitations
- Step-by-step execution instructions
- Alternative trigger type recommendations
- Comprehensive error handling

Testing Results

✅ Working MCP Tools

list_workflows: Returns all workflows correctly
get_workflow: Returns detailed workflow information
create_workflow: Creates workflows via MCP
update_workflow: Updates workflows via MCP
list_executions: Shows existing executions
get_execution: Returns execution details

✅ CFP Automation Workflows

Successfully imported 3 sophisticated CFP scraping workflows
Enhanced workflow with Google Gemini AI integration working
Workflows can be managed programmatically via MCP tools
Manual execution confirmed working via n8n web interface

Impact

Before: MCP server completely non-functional due to transport conflicts and API parsing errors
After: Fully functional MCP server with comprehensive workflow management capabilities
Benefit: Enables AI-powered CFP automation with programmatic workflow control

Files Changed

src/index.ts - Transport mode detection
src/services/n8nApiWrapper.ts - API parsing fixes and execution guidance
src/services/environmentManager.ts - Base