n8n-validation-expert_skill

Overview

This skill helps interpret n8n validation results and guides you to fix errors, warnings, and suggestions so workflows activate and run reliably. It explains error severity, common error types, validation profiles, the iterative validation loop, and automated fixes for operator structure issues. Use it to speed troubleshooting and reduce false positives before deployment.

How this skill works

It inspects validation output from node- and workflow-level checks and categorizes findings as Errors (must fix), Warnings (should fix), or Suggestions (optional). It maps each issue to concrete remediation steps, points to the appropriate validation profile, and recommends iterative validation cycles. It also describes the auto-sanitization behaviors that correct common operator metadata problems on workflow save.

When to use it

• When validate_node or validate_workflow returns errors blocking activation
• When warnings appear and you need to decide if they are false positives
• When expressions or node references report invalid syntax or missing nodes
• Before deployment to run the recommended runtime profile validation
• When operator structure issues appear after workflow edits or saves

Best practices

• Validate after every meaningful change and fix errors first, then warnings
• Use the runtime profile for pre-deployment checks and ai-friendly for AI-generated configs
• Address one error at a time; expect 2–3 validate→fix iterations
• Trust auto-sanitization for operator metadata and preview fixes before applying
• Use get_node to inspect required fields and types when resolving missing_required or type_mismatch

Example use cases

• Fix a missing_required error for a Slack channel field so the workflow can activate
• Resolve invalid_expression by correcting n8n expression syntax (add {{}} and correct node names)
• Run validate_workflow to locate broken connections and use cleanStaleConnections to remove them
• Apply autofix preview to add missing singleValue flags for unary boolean operators
• Choose ai-friendly profile to reduce false positives when an AI agent generates node configs