n8n MCP Server

Opinionated workflow automation for n8n. Enforces best practices, auto-fixes issues, and prevents mistakes.

Why This MCP?

The problem: Other n8n MCPs replace entire nodes when you update one field. Change a message? Lose your channel ID, auth settings, everything else. No undo. And they bundle 70MB of node docs you can just Google.

This MCP is opinionated:

• Patches, not replaces - Update one field, keep everything else
• Auto-cleanup - Every create/update validates, auto-fixes, and formats automatically
• Auto-snapshots - Every mutation saves a version first. Always have rollback.
• Node type validation - Blocks invalid node types with suggestions before they hit n8n
• Expression validation - Catches $json refs that break on reorder, circular deps, missing nodes
• Enforces conventions - snake_case naming, explicit references, recommends env vars
• Lightweight - ~1,500 lines, zero runtime dependencies

| | This MCP | Others | |--|----------|--------| | Update a node | Preserves untouched params | Loses them | | After create/update | Auto-validates, auto-fixes, formats | Manual cleanup | | Invalid node types | Blocked with suggestions | API error | | Before mutations | Auto-saves version | Hope you backed up | | Expression validation | Syntax, refs, circular deps | Basic | | Size | ~1,500 LOC | 10k+ LOC, 70MB SQLite |

Setup

Add to your MCP client config:

{
  "mcpServers": {
    "n8n": {
      "command": "npx",
      "args": ["-y", "@pagelines/n8n-mcp"],
      "env": {
        "N8N_API_URL": "https://your-n8n.com",
        "N8N_API_KEY": "your-api-key"
      }
    }
  }
}

No install step needed - npx handles it.

Reference

Tools

| Category | Tools | |----------|-------| | Workflow | list get create update delete activate deactivate execute | | Execution | list get | | Validation | validate autofix format | | Discovery | node_types_list | | Versions | list get save rollback diff stats |

Opinions Enforced

These rules are checked and auto-fixed on every workflow_create and workflow_update:

| Rule | Severity | Auto-fix | |------|----------|----------| | snake_case naming | warning | Yes | | Explicit refs ($('node') not $json) | warning | Yes | | AI structured output settings | warning | Yes | | Invalid node types | error | Blocked | | Hardcoded secrets | info | No | | Orphan nodes | warning | No | | Expression syntax | error | No | | Circular references | error | No |

Config

| Variable | Default | Description | |----------|---------|-------------| | N8N_API_URL | required | n8n instance URL | | N8N_API_KEY | required | API key | | N8N_MCP_VERSIONS | true | Enable version control | | N8N_MCP_MAX_VERSIONS | 20 | Max snapshots per workflow |

Docs

• Best Practices - Expression patterns, config nodes, AI settings
• Node Config - Human-editable node settings
• Architecture - Technical reference

License

MIT - PageLines