Interpret validation errors and guide fixing them. Use when encountering validation errors, validation warnings, false positives, operator structure issues, or need help understanding validation results. Also use when asking about validation profiles, error types, or the validation loop process.
Add this skill
npx mdskills install czlonkowski/n8n-validation-expertComprehensive validation guidance with clear error taxonomy, iterative workflow patterns, and practical recovery strategies
Expert guidance for interpreting and fixing n8n validation errors.
Skill Name: n8n Validation Expert Priority: Medium Purpose: Interpret validation errors and guide systematic fixing through the validation loop
Validation errors are common:
Key insight: Validation is an iterative process, not a one-shot fix!
Error Severity Levels
The Validation Loop
Validation Profiles
minimal - Quick checks, most permissiveruntime - Recommended for most use casesai-friendly - Reduces false positives for AI workflowsstrict - Maximum safety, many warningsAuto-Sanitization System
False Positives
ai-friendly profile to reduce by 60%n8n-validation-expert/
├── SKILL.md (690 lines)
│ Core validation concepts and workflow
│ - Validation philosophy
│ - Error severity levels
│ - The validation loop pattern
│ - Validation profiles
│ - Common error types
│ - Auto-sanitization system
│ - Workflow validation
│ - Recovery strategies
│ - Best practices
│
├── ERROR_CATALOG.md (865 lines)
│ Complete error reference with examples
│ - 9 error types with real examples
│ - missing_required (45% of errors)
│ - invalid_value (28%)
│ - type_mismatch (12%)
│ - invalid_expression (8%)
│ - invalid_reference (5%)
│ - operator_structure (2%, auto-fixed)
│ - Recovery patterns
│ - Summary with frequencies
│
├── FALSE_POSITIVES.md (669 lines)
│ When warnings are acceptable
│ - Philosophy of warning acceptance
│ - 6 common false positive types
│ - When acceptable vs when to fix
│ - Validation profile strategies
│ - Decision framework
│ - Documentation template
│ - Known n8n issues (#304, #306, #338)
│
└── README.md (this file)
Skill metadata and statistics
Total: ~2,224 lines across 4 files
| Error Type | Priority | Auto-Fix | Severity |
|---|---|---|---|
| missing_required | Highest | ❌ | Error |
| invalid_value | High | ❌ | Error |
| type_mismatch | Medium | ❌ | Error |
| invalid_expression | Medium | ❌ | Error |
| invalid_reference | Low | ❌ | Error |
| operator_structure | Low | ✅ | Warning |
Don't expect to get it right on the first try. Multiple validation cycles (typically 2-3) are normal and expected!
Many validation warnings are acceptable in production workflows. This skill helps you recognize which ones to address vs. which to ignore.
Certain error types (like operator structure issues) are automatically fixed by n8n. Don't waste time manually fixing these!
ai-friendly reduces false positives by 60%runtime is the sweet spot for most use casesstrict has value pre-production but is noisyValidation errors include fix guidance - read them carefully!
// Iteration 1
let config = {
resource: "channel",
operation: "create"
};
const result1 = validate_node_operation({
nodeType: "nodes-base.slack",
config,
profile: "runtime"
});
// → Error: Missing "name"
// Iteration 2
config.name = "general";
const result2 = validate_node_operation({...});
// → Valid! ✅
// Run validation
const result = validate_node_operation({
nodeType: "nodes-base.slack",
config,
profile: "runtime"
});
// Fix errors (must fix)
if (!result.valid) {
result.errors.forEach(error => {
console.log(`MUST FIX: ${error.message}`);
});
}
// Review warnings (context-dependent)
result.warnings.forEach(warning => {
if (warning.type === 'best_practice' && isDevWorkflow) {
console.log(`ACCEPTABLE: ${warning.message}`);
} else {
console.log(`SHOULD FIX: ${warning.message}`);
}
});
// Check what can be auto-fixed
const preview = n8n_autofix_workflow({
id: "workflow-id",
applyFixes: false // Preview mode
});
console.log(`Can auto-fix: ${preview.fixCount} issues`);
// Apply fixes
if (preview.fixCount > 0) {
n8n_autofix_workflow({
id: "workflow-id",
applyFixes: true
});
}
Trigger phrases:
Common scenarios:
Evaluations: 4 test scenarios
eval-001-missing-required-field.json
eval-002-false-positive.json
eval-003-auto-sanitization.json
eval-004-validation-loop.json
Before this skill:
After this skill:
Conceived by Romuald Członkowski - www.aiadvisors.pl/en
Part of the n8n-skills meta-skill collection.
Install via CLI
npx mdskills install czlonkowski/n8n-validation-expertN8n Validation Expert is a free, open-source AI agent skill. Interpret validation errors and guide fixing them. Use when encountering validation errors, validation warnings, false positives, operator structure issues, or need help understanding validation results. Also use when asking about validation profiles, error types, or the validation loop process.
Install N8n Validation Expert with a single command:
npx mdskills install czlonkowski/n8n-validation-expertThis downloads the skill files into your project and your AI agent picks them up automatically.
N8n Validation Expert works with Claude Code, Claude Desktop, Cursor, Vscode Copilot, Windsurf, Continue Dev, Codex, Gemini Cli, Amp, Roo Code, Goose, Opencode, Trae, Qodo, Command Code. Skills use the open SKILL.md format which is compatible with any AI coding agent that reads markdown instructions.