| 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.
