n8n-MCP is a Model Context Protocol server that gives AI assistants structured knowledge of n8n's workflow-automation nodes, including their properties, operations, documentation, and examples. It helps developers use AI assistants to create and work with n8n workflows. The catalogue contains skills, agents, and instructions for using it.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add czlonkowski/n8n-mcp --skill n8n-validation-expertgit clone --depth 1 https://github.com/czlonkowski/n8n-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/czlonkowski/n8n-mcp/n8n-validation-expert)<a href="https://agentmods.dev/skills/czlonkowski/n8n-mcp/n8n-validation-expert"><img src="https://agentmods.dev/badge/skills/czlonkowski/n8n-mcp/n8n-validation-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/czlonkowski/n8n-mcp/n8n-validation-expert"><img src="https://agentmods.dev/badge/skills/czlonkowski/n8n-mcp/n8n-validation-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Snyk pass
- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Memory Poisoning · line 198 Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00091 | $0.05004 |
| Opus 5 | $0.00046 | $0.02502 |
| Sonnet 5 | $0.00018 | $0.01001 |
| Haiku 4.5 | $0.00009 | $0.00500 |
Grade A, and why
n8n-validation-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 13d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
1 near-identical copy found in the catalogue:
- n8n-validation-expert — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 515 lines — stays where its author put it; the contents beside it link to each section on GitHub.
n8n Validation Expert
Expert guide for interpreting and fixing n8n validation errors.
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!
Error Severity Levels
1. Errors (Must Fix)
Blocks workflow execution - Must be resolved before activation
Types:
missing_required- Required field not providedinvalid_value- Value doesn't match allowed optionstype_mismatch- Wrong data type (string instead of number)invalid_reference- Referenced node doesn't existinvalid_expression- Expression syntax error
Example:
{
"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 — surfaces underai-friendly/strictonlydeprecated- Using old API/feature — surfaces under every profilesecurity- Hardcoded secrets, unauthenticated webhooks — surfaces under every profileperformance- Potential performance issue — advisory,ai-friendly/strict
Example (best-practice — appears under ai-friendly / strict):
{
"type": "warning",
"nodeName": "Slack",
"message": "Slack API can have rate limits and transient failures"
}
3. Suggestions (Optional)
Nice to have - Improvements that could enhance workflow
Types:
optimization- Could be more efficientalternative- Better way to achieve same result
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)
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 13d ago First seen · 515 lines · 91 tokens per session scan A 1b81cfd31b4f
n8n-validation-expert is a skill published in the GitHub repository czlonkowski/n8n-mcp (22,874 stars, last pushed yesterday), licensed MIT. It adds 91 tokens to every session and 5,004 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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