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 mirza-javed/n8n-mcp --skill n8n-code-toolgit clone --depth 1 https://github.com/mirza-javed/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/mirza-javed/n8n-mcp/n8n-code-tool)<a href="https://agentmods.dev/skills/mirza-javed/n8n-mcp/n8n-code-tool"><img src="https://agentmods.dev/badge/skills/mirza-javed/n8n-mcp/n8n-code-tool/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/mirza-javed/n8n-mcp/n8n-code-tool"><img src="https://agentmods.dev/badge/skills/mirza-javed/n8n-mcp/n8n-code-tool.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00221 | $0.04138 |
| Opus 5 | $0.00111 | $0.02069 |
| Sonnet 5 | $0.00044 | $0.00828 |
| Haiku 4.5 | $0.00022 | $0.00414 |
Grade A, and why
n8n-code-tool 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 8d 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.
This is a copy
100% identical to n8n-code-tool — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 339 lines — stays where its author put it; the contents beside it link to each section on GitHub.
n8n Custom Code Tool
Expert guidance for writing code inside @n8n/n8n-nodes-langchain.toolCode — the tool an AI Agent can invoke, not the regular workflow Code node.
⚠️ This is NOT the Code node
The Custom Code Tool looks like a Code node in the editor — same JavaScript editor, similar layout — but it is a completely different node from a different package with a different runtime contract.
| Code node | Custom Code Tool | |
|---|---|---|
| Node type | n8n-nodes-base.code |
@n8n/n8n-nodes-langchain.toolCode |
| Package | n8n-nodes-base |
@n8n/n8n-nodes-langchain |
| Invoked by | Previous node (workflow flow) | AI Agent (LangChain) |
| Input | $input.all() — item stream |
query — string or object from LLM |
| Return | [{json: {...}}] (items array) |
A string |
$fromAI() |
N/A | Not available (see Errors) |
| HTTP helper | this.helpers.httpRequest (auth helpers blocked) |
Not exposed to the tool sandbox |
| State | Per-run execution data | No getContext, no $getWorkflowStaticData |
If you treat it like a Code node, it fails. The rest of this skill covers the Code Tool's actual contract.
Quick Start
Minimal JavaScript Code Tool
// `query` is whatever the AI sent (a string by default)
return `You asked: ${query}`;
Minimal Python Code Tool
# `_query` is whatever the AI sent (a string by default)
return f"You asked: {_query}"
Essential Rules
- Return a string. Numbers are auto-converted. Anything else throws
"The response property should be a string, but it is an object". - Input variable is fixed:
query(JS),_query(Python). You cannot rename it. - Do NOT use
$fromAI()inside the Code Tool sandbox — it throws"No execution data available". - Do NOT use
[{json: {...}}]return format — that's for Code nodes. Throws"Wrong output type returned". - Use a descriptive tool name (letters/numbers/underscores, v1.1+). The agent calls the tool by its name.
- Write a precise description — the LLM decides whether to invoke the tool based on it.
What ships with it
3 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.
- 8d ago First seen · 339 lines · 0 tokens per session scan A 7d3e4654799f
n8n-code-tool is a skill published in the GitHub repository mirza-javed/n8n-mcp (0 stars, last pushed 2mo ago), licensed MIT. It adds 221 tokens to every session and 4,138 once invoked, about $0.0011 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to n8n-code-tool, differing in 2 lines, and is treated as a copy.
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