--- name: n8n-validation-expert description: "n8n Validation Expert workflow skill. Use this skill when the user needs Expert guide for interpreting and fixing n8n validation errors and the operator should preserve the upstream workflow, copied support files, and provenance before merging or handing off." version: "0.0.1" category: frontend tags: ["n8n-validation-expert", "expert", "guide", "for", "interpreting", "and", "fixing", "n8n"] complexity: advanced risk: caution tools: ["codex-cli", "claude-code", "cursor", "gemini-cli", "opencode"] source: community author: "sickn33" date_added: "2026-04-15" date_updated: "2026-04-25" --- # n8n Validation Expert ## Overview This public intake copy packages `plugins/antigravity-awesome-skills-claude/skills/n8n-validation-expert` from `https://github.com/sickn33/antigravity-awesome-skills` into the native Omni Skills editorial shape without hiding its origin. Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow. This intake keeps the copied upstream files intact and uses the `external_source` block in `metadata.json` plus `ORIGIN.md` as the provenance anchor for review. # n8n Validation Expert Expert guide for interpreting and fixing n8n validation errors. Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Validation Philosophy, Error Severity Levels, The Validation Loop, Validation Profiles, Common Error Types, Auto-Sanitization System. ## When to Use This Skill Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request. - You need to interpret or fix validation errors in an n8n workflow. - The task involves missingrequired, invalidvalue, expression failures, or iterative validate-fix loops. - You want concrete remediation guidance for workflow validation output. - Use when the request clearly matches the imported source intent: Expert guide for interpreting and fixing n8n validation errors. - Use when the operator should preserve upstream workflow detail instead of rewriting the process from scratch. - Use when provenance needs to stay visible in the answer, PR, or review packet. ## Operating Table | Situation | Start here | Why it matters | | --- | --- | --- | | First-time use | `metadata.json` | Confirms repository, branch, commit, and imported path through the `external_source` block before touching the copied workflow | | Provenance review | `ORIGIN.md` | Gives reviewers a plain-language audit trail for the imported source | | Workflow execution | `SKILL.md` | Starts with the smallest copied file that materially changes execution | | Supporting context | `SKILL.md` | Adds the next most relevant copied source file without loading the entire package | | Handoff decision | `## Related Skills` | Helps the operator switch to a stronger native skill when the task drifts | ## Workflow This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow. 1. Node configurations - Each node valid 2. Connections - No broken references 3. Expressions - Syntax and references valid 4. Flow - Logical workflow structure 5. Confirm the user goal, the scope of the imported workflow, and whether this skill is still the right router for the task. 6. Read the overview and provenance files before loading any copied upstream support files. 7. Load only the references, examples, prompts, or scripts that materially change the outcome for the current request. ### Imported Workflow Notes #### Imported: Workflow Validation ### validate_workflow (Structure) **Validates entire workflow**, not just individual nodes **Checks**: 1. **Node configurations** - Each node valid 2. **Connections** - No broken references 3. **Expressions** - Syntax and references valid 4. **Flow** - Logical workflow structure **Example**: ```javascript validate_workflow({ workflow: { nodes: [...], connections: {...} }, options: { validateNodes: true, validateConnections: true, validateExpressions: true, profile: "runtime" } }) ``` ### Common Workflow Errors #### 1. Broken Connections ```json { "error": "Connection from 'Transform' to 'NonExistent' - target node not found" } ``` **Fix**: Remove stale connection or create missing node #### 2. Circular Dependencies ```json { "error": "Circular dependency detected: Node A → Node B → Node A" } ``` **Fix**: Restructure workflow to remove loop #### 3. Multiple Start Nodes ```json { "warning": "Multiple trigger nodes found - only one will execute" } ``` **Fix**: Remove extra triggers or split into separate workflows #### 4. Disconnected Nodes ```json { "warning": "Node 'Transform' is not connected to workflow flow" } ``` **Fix**: Connect node or remove if unused --- #### Imported: Summary **Key Points**: 1. **Validation is iterative** (avg 2-3 cycles, 23s + 58s) 2. **Errors must be fixed**, warnings are optional 3. **Auto-sanitization** fixes operator structures automatically 4. **Use runtime profile** for balanced validation 5. **False positives exist** - learn to recognize them 6. **Read error messages** - they contain fix guidance **Validation Process**: 1. Validate → Read errors → Fix → Validate again 2. Repeat until valid (usually 2-3 iterations) 3. Review warnings and decide if acceptable 4. Deploy with confidence **Related Skills**: - n8n MCP Tools Expert - Use validation tools correctly - n8n Expression Syntax - Fix expression errors - n8n Node Configuration - Understand required fields #### Imported: Validation Philosophy **Validate early, validate often** Validation is typically iterative: - Expect validation feedback loops - Usually 2-3 validate → fix cycles - Average: 23s thinking about errors, 58s fixing them **Key insight**: Validation is an iterative process, not one-shot! --- ## Examples ### Example 1: Ask for the upstream workflow directly ```text Use @n8n-validation-expert to handle . Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer. ``` **Explanation:** This is the safest starting point when the operator needs the imported workflow, but not the entire repository. ### Example 2: Ask for a provenance-grounded review ```text Review @n8n-validation-expert against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why. ``` **Explanation:** Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection. ### Example 3: Narrow the copied support files before execution ```text Use @n8n-validation-expert for . Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding. ``` **Explanation:** This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default. ### Example 4: Build a reviewer packet ```text Review @n8n-validation-expert using the copied upstream files plus provenance, then summarize any gaps before merge. ``` **Explanation:** This is useful when the PR is waiting for human review and you want a repeatable audit packet. ## Best Practices Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution. - Validate after every significant change - Read error messages completely - Fix errors iteratively (one at a time) - Use runtime profile for pre-deployment - Check valid field before assuming success - Trust auto-sanitization for operator issues - Use get_node when unclear about requirements ### Imported Operating Notes #### Imported: Best Practices ### ✅ Do - Validate after every significant change - Read error messages completely - Fix errors iteratively (one at a time) - Use `runtime` profile for pre-deployment - Check `valid` field before assuming success - Trust auto-sanitization for operator issues - Use `get_node` when unclear about requirements - Document false positives you accept ### ❌ Don't - Skip validation before activation - Try to fix all errors at once - Ignore error messages - Use `strict` profile during development (too noisy) - Assume validation passed (always check result) - Manually fix auto-sanitization issues - Deploy with unresolved errors - Ignore all warnings (some are important!) --- ## Troubleshooting ### Problem: The operator skipped the imported context and answered too generically **Symptoms:** The result ignores the upstream workflow in `plugins/antigravity-awesome-skills-claude/skills/n8n-validation-expert`, fails to mention provenance, or does not use any copied source files at all. **Solution:** Re-open `metadata.json`, `ORIGIN.md`, and the most relevant copied upstream files. Check the `external_source` block first, then restate the provenance before continuing. ### Problem: The imported workflow feels incomplete during review **Symptoms:** Reviewers can see the generated `SKILL.md`, but they cannot quickly tell which references, examples, or scripts matter for the current task. **Solution:** Point at the exact copied references, examples, scripts, or assets that justify the path you took. If the gap is still real, record it in the PR instead of hiding it. ### Problem: The task drifted into a different specialization **Symptoms:** The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. **Solution:** Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind. ## Related Skills - `@00-andruia-consultant` - Use when the work is better handled by that native specialization after this imported skill establishes context. - `@00-andruia-consultant-v2` - Use when the work is better handled by that native specialization after this imported skill establishes context. - `@10-andruia-skill-smith` - Use when the work is better handled by that native specialization after this imported skill establishes context. - `@10-andruia-skill-smith-v2` - Use when the work is better handled by that native specialization after this imported skill establishes context. ## Additional Resources Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding. | Resource family | What it gives the reviewer | Example path | | --- | --- | --- | | `references` | copied reference notes, guides, or background material from upstream | `references/n/a` | | `examples` | worked examples or reusable prompts copied from upstream | `examples/n/a` | | `scripts` | upstream helper scripts that change execution or validation | `scripts/n/a` | | `agents` | routing or delegation notes that are genuinely part of the imported package | `agents/n/a` | | `assets` | supporting assets or schemas copied from the source package | `assets/n/a` | ### Imported Reference Notes #### Imported: Error Severity Levels ### 1. Errors (Must Fix) **Blocks workflow execution** - Must be resolved before activation **Types**: - `missing_required` - Required field not provided - `invalid_value` - Value doesn't match allowed options - `type_mismatch` - Wrong data type (string instead of number) - `invalid_reference` - Referenced node doesn't exist - `invalid_expression` - Expression syntax error **Example**: ```json { "type": "missing_required", "property": "channel", "message": "Channel name is required", "fix": "Provide a channel name (lowercase, no spaces, 1-80 characters)" } ``` ### 2. Warnings (Should Fix) **Doesn't block execution** - Workflow can be activated but may have issues **Types**: - `best_practice` - Recommended but not required - `deprecated` - Using old API/feature - `performance` - Potential performance issue **Example**: ```json { "type": "best_practice", "property": "errorHandling", "message": "Slack API can have rate limits", "suggestion": "Add onError: 'continueRegularOutput' with retryOnFail" } ``` ### 3. Suggestions (Optional) **Nice to have** - Improvements that could enhance workflow **Types**: - `optimization` - Could be more efficient - `alternative` - Better way to achieve same result --- #### Imported: The Validation Loop ### Pattern from Telemetry **7,841 occurrences** of this pattern: ``` 1. Configure node ↓ 2. validate_node (23 seconds thinking about errors) ↓ 3. Read error messages carefully ↓ 4. Fix errors ↓ 5. validate_node again (58 seconds fixing) ↓ 6. Repeat until valid (usually 2-3 iterations) ``` ### Example ```javascript // Iteration 1 let config = { resource: "channel", operation: "create" }; const result1 = validate_node({ nodeType: "nodes-base.slack", config, profile: "runtime" }); // → Error: Missing "name" // ⏱️ 23 seconds thinking... // Iteration 2 config.name = "general"; const result2 = validate_node({ nodeType: "nodes-base.slack", config, profile: "runtime" }); // → Error: Missing "text" // ⏱️ 58 seconds fixing... // Iteration 3 config.text = "Hello!"; const result3 = validate_node({ nodeType: "nodes-base.slack", config, profile: "runtime" }); // → Valid! ✅ ``` **This is normal!** Don't be discouraged by multiple iterations. --- #### Imported: Validation Profiles Choose the right profile for your stage: ### minimal **Use when**: Quick checks during editing **Validates**: - Only required fields - Basic structure **Pros**: Fastest, most permissive **Cons**: May miss issues ### runtime (RECOMMENDED) **Use when**: Pre-deployment validation **Validates**: - Required fields - Value types - Allowed values - Basic dependencies **Pros**: Balanced, catches real errors **Cons**: Some edge cases missed **This is the recommended profile for most use cases** ### ai-friendly **Use when**: AI-generated configurations **Validates**: - Same as runtime - Reduces false positives - More tolerant of minor issues **Pros**: Less noisy for AI workflows **Cons**: May allow some questionable configs ### strict **Use when**: Production deployment, critical workflows **Validates**: - Everything - Best practices - Performance concerns - Security issues **Pros**: Maximum safety **Cons**: Many warnings, some false positives --- #### Imported: Common Error Types ### 1. missing_required **What it means**: A required field is not provided **How to fix**: 1. Use `get_node` to see required fields 2. Add the missing field to your configuration 3. Provide an appropriate value **Example**: ```javascript // Error { "type": "missing_required", "property": "channel", "message": "Channel name is required" } // Fix config.channel = "#general"; ``` ### 2. invalid_value **What it means**: Value doesn't match allowed options **How to fix**: 1. Check error message for allowed values 2. Use `get_node` to see options 3. Update to a valid value **Example**: ```javascript // Error { "type": "invalid_value", "property": "operation", "message": "Operation must be one of: post, update, delete", "current": "send" } // Fix config.operation = "post"; // Use valid operation ``` ### 3. type_mismatch **What it means**: Wrong data type for field **How to fix**: 1. Check expected type in error message 2. Convert value to correct type **Example**: ```javascript // Error { "type": "type_mismatch", "property": "limit", "message": "Expected number, got string", "current": "100" } // Fix config.limit = 100; // Number, not string ``` ### 4. invalid_expression **What it means**: Expression syntax error **How to fix**: 1. Use n8n Expression Syntax skill 2. Check for missing `{{}}` or typos 3. Verify node/field references **Example**: ```javascript // Error { "type": "invalid_expression", "property": "text", "message": "Invalid expression: $json.name", "current": "$json.name" } // Fix config.text = "={{$json.name}}"; // Add {{}} ``` ### 5. invalid_reference **What it means**: Referenced node doesn't exist **How to fix**: 1. Check node name spelling 2. Verify node exists in workflow 3. Update reference to correct name **Example**: ```javascript // Error { "type": "invalid_reference", "property": "expression", "message": "Node 'HTTP Requets' does not exist", "current": "={{$node['HTTP Requets'].json.data}}" } // Fix - correct typo config.expression = "={{$node['HTTP Request'].json.data}}"; ``` --- #### Imported: Auto-Sanitization System ### What It Does **Automatically fixes common operator structure issues** on ANY workflow update **Runs when**: - `n8n_create_workflow` - `n8n_update_partial_workflow` - Any workflow save operation ### What It Fixes #### 1. Binary Operators (Two Values) **Operators**: equals, notEquals, contains, notContains, greaterThan, lessThan, startsWith, endsWith **Fix**: Removes `singleValue` property (binary operators compare two values) **Before**: ```javascript { "type": "boolean", "operation": "equals", "singleValue": true // ❌ Wrong! } ``` **After** (automatic): ```javascript { "type": "boolean", "operation": "equals" // singleValue removed ✅ } ``` #### 2. Unary Operators (One Value) **Operators**: isEmpty, isNotEmpty, true, false **Fix**: Adds `singleValue: true` (unary operators check single value) **Before**: ```javascript { "type": "boolean", "operation": "isEmpty" // Missing singleValue ❌ } ``` **After** (automatic): ```javascript { "type": "boolean", "operation": "isEmpty", "singleValue": true // ✅ Added } ``` #### 3. IF/Switch Metadata **Fix**: Adds complete `conditions.options` metadata for IF v2.2+ and Switch v3.2+ ### What It CANNOT Fix #### 1. Broken Connections References to non-existent nodes **Solution**: Use `cleanStaleConnections` operation in `n8n_update_partial_workflow` #### 2. Branch Count Mismatches 3 Switch rules but only 2 output connections **Solution**: Add missing connections or remove extra rules #### 3. Paradoxical Corrupt States API returns corrupt data but rejects updates **Solution**: May require manual database intervention --- #### Imported: False Positives ### What Are They? Validation warnings that are technically "wrong" but acceptable in your use case ### Common False Positives #### 1. "Missing error handling" **Warning**: No error handling configured **When acceptable**: - Simple workflows where failures are obvious - Testing/development workflows - Non-critical notifications **When to fix**: Production workflows handling important data #### 2. "No retry logic" **Warning**: Node doesn't retry on failure **When acceptable**: - APIs with their own retry logic - Idempotent operations - Manual trigger workflows **When to fix**: Flaky external services, production automation #### 3. "Missing rate limiting" **Warning**: No rate limiting for API calls **When acceptable**: - Internal APIs with no limits - Low-volume workflows - APIs with server-side rate limiting **When to fix**: Public APIs, high-volume workflows #### 4. "Unbounded query" **Warning**: SELECT without LIMIT **When acceptable**: - Small known datasets - Aggregation queries - Development/testing **When to fix**: Production queries on large tables ### Reducing False Positives **Use `ai-friendly` profile**: ```javascript validate_node({ nodeType: "nodes-base.slack", config: {...}, profile: "ai-friendly" // Fewer false positives }) ``` --- #### Imported: Validation Result Structure ### Complete Response ```javascript { "valid": false, "errors": [ { "type": "missing_required", "property": "channel", "message": "Channel name is required", "fix": "Provide a channel name (lowercase, no spaces)" } ], "warnings": [ { "type": "best_practice", "property": "errorHandling", "message": "Slack API can have rate limits", "suggestion": "Add onError: 'continueRegularOutput'" } ], "suggestions": [ { "type": "optimization", "message": "Consider using batch operations for multiple messages" } ], "summary": { "hasErrors": true, "errorCount": 1, "warningCount": 1, "suggestionCount": 1 } } ``` ### How to Read It #### 1. Check `valid` field ```javascript if (result.valid) { // ✅ Configuration is valid } else { // ❌ Has errors - must fix before deployment } ``` #### 2. Fix errors first ```javascript result.errors.forEach(error => { console.log(`Error in ${error.property}: ${error.message}`); console.log(`Fix: ${error.fix}`); }); ``` #### 3. Review warnings ```javascript result.warnings.forEach(warning => { console.log(`Warning: ${warning.message}`); console.log(`Suggestion: ${warning.suggestion}`); // Decide if you need to address this }); ``` #### 4. Consider suggestions ```javascript // Optional improvements // Not required but may enhance workflow ``` --- #### Imported: Recovery Strategies ### Strategy 1: Start Fresh **When**: Configuration is severely broken **Steps**: 1. Note required fields from `get_node` 2. Create minimal valid configuration 3. Add features incrementally 4. Validate after each addition ### Strategy 2: Binary Search **When**: Workflow validates but executes incorrectly **Steps**: 1. Remove half the nodes 2. Validate and test 3. If works: problem is in removed nodes 4. If fails: problem is in remaining nodes 5. Repeat until problem isolated ### Strategy 3: Clean Stale Connections **When**: "Node not found" errors **Steps**: ```javascript n8n_update_partial_workflow({ id: "workflow-id", operations: [{ type: "cleanStaleConnections" }] }) ``` ### Strategy 4: Use Auto-fix **When**: Operator structure errors **Steps**: ```javascript n8n_autofix_workflow({ id: "workflow-id", applyFixes: false // Preview first }) // Review fixes, then apply n8n_autofix_workflow({ id: "workflow-id", applyFixes: true }) ``` --- #### Imported: Detailed Guides For comprehensive error catalogs and false positive examples: - **ERROR_CATALOG.md** - Complete list of error types with examples - **FALSE_POSITIVES.md** - When warnings are acceptable --- #### Imported: Limitations - Use this skill only when the task clearly matches the scope described above. - Do not treat the output as a substitute for environment-specific validation, testing, or expert review. - Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.