n8n-workflow-validation

name	n8n-workflow-validation
description	Use this to validate an n8n workflow before saving it as an artifact, or whenever a user asks to check, lint, or validate an existing workflow. Runs validate_n8n_workflow, fixes every reported error, and re-validates until the workflow is VALID. Validation is mandatory before create_artifact.
tags	["n8n","workflow","validation","yaml","json"]

n8n-workflow-validation

When to use

Apply this skill:

• Always before persisting a workflow. Never call create_artifact with a workflow that has not passed validate_n8n_workflow in this turn. This is the mandatory final gate of the n8n-workflow-generation skill (its Step 3).
• On demand, whenever the user pastes a workflow and asks to "validate", "check", "lint", "is this correct?", or "will this import into n8n?". In that case run the validation and report the result - only create an artifact if the user also asked you to save it.

A workflow-generation task is only complete once validate_n8n_workflow reports VALID.

Workflow

Execute these steps in order.

Step 1 - Collect the workflow content

Take the complete workflow as a single string - the full YAML or JSON document, not a fragment. If you just drafted it, use exactly the content you intend to save.

Step 2 - Validate (mandatory)

Call validate_n8n_workflow with:

• workflow_content: the entire workflow document.
• format: yaml, json, or auto (default). Pass auto unless you know the format and the auto-detector guessed wrong.

The tool first checks that the content parses as YAML or JSON, then checks it against the n8n workflow schema (see "What the validator checks").

Step 3 - Interpret the result

• VALID - the workflow passed. Address any warnings too if the user asked for a production-grade flow; otherwise proceed.
• INVALID - the response lists concrete Errors. Do not proceed. Go to Step 4.

Step 4 - Fix every error, then re-validate (loop)

For each reported error, edit the workflow to correct it (see "Common fixes"), then call validate_n8n_workflow again on the corrected content. Repeat this fix-and-revalidate loop until the result is VALID. Never stop at INVALID and never save an INVALID workflow.

If an error is genuinely ambiguous (for example a required credential the user has not supplied), fix everything you can and then ask the user for the missing detail rather than shipping an invalid workflow.

Step 5 - Proceed or report

• Inside the generation flow: once VALID, continue to create_artifact.
• Standalone validation request: report VALID / INVALID, list the errors you fixed (if any) and any remaining warnings, and return the corrected workflow.

What the validator checks

validate_n8n_workflow enforces the following. Treat every error as a hard blocker and every warning as advisory.

Parseability (error)

• Content must parse as valid YAML or JSON. A syntax error fails immediately before any schema checks run.

Workflow structure

• nodes: must contain at least one node (error if empty).
• name: recommended (warning if missing).

Nodes (each entry in nodes)

• id: required and unique across the workflow (error).
• name: required (error).
• type: required and must match n8n-nodes-base.<node> or @n8n/n8n-nodes-langchain.<node> (error).
• position: must be an array of exactly two numbers [x, y] (error).
• parameters: use {} when the node needs none (warning if omitted).

Connections (each entry in connections)

• source / target: required, and each must reference an existing node id (error).
• A node may not connect to itself (error).
• sourceIndex / targetIndex: must be >= 0 (error).
• Multi-node workflow with no connections defined (warning - nodes will not be linked).

Logic

• At least one trigger node (webhook, schedule, manual, cron, timer, …) is recommended so the workflow can run automatically (warning if none).

Common fixes

Error	Fix
Invalid YAML/JSON format	Correct the syntax (indentation, quoting, brackets) and re-validate.
Unable to detect workflow format	Ensure the content is valid YAML or JSON, or pass format explicitly.
Workflow must contain at least one node	Add the node(s) the workflow needs, including a trigger.
'id' is required / duplicate node ID	Give every node a unique id.
'name' is required	Add a human-readable name to the node.
invalid node type format	Use a fully-qualified type, e.g. n8n-nodes-base.httpRequest. Look it up with search_n8n_docs if unsure.
'position' must be an array of exactly 2 numbers	Set position: [x, y] with two numeric values.
source/target node '…' does not exist	Point the connection at real node ids.
node cannot connect to itself	Remove or re-target the self-referencing connection.
sourceIndex/targetIndex must be >= 0	Use non-negative output/input indexes.

Tools

• validate_n8n_workflow - schema + parse validation (this skill's core tool).
• search_n8n_docs - look up correct node types and parameters when fixing invalid node type format or unknown-node errors.