n8n-validation-expert

Validation errors in n8n indicate missing fields, incorrect data types, or malformed expressions. Identify the error type, locate the affected node field, and provide the correct value format—the validation system guides you through each fix iteratively until your workflow passes.

This error means the Slack node's channel field is empty or missing. Provide a valid channel name or ID in that field; the validation will confirm once the requirement is satisfied.

Not all validation warnings block execution. This Skill distinguishes critical errors from harmless warnings, explaining which ones can be safely ignored and which require fixes before your workflow runs.

Configuration errors vary by node—HTTP Request, Postgres, Slack each have specific field and expression requirements. Systematic validation across node types catches type mismatches, invalid references, and operator structure problems, guiding fixes for each.

Use validation interpretation to decode error messages, understand why each field failed, and apply targeted fixes. The validate-fix-validate loop eliminates guessing by showing exact problems and required corrections.