---
title: "n8n Custom Code Tool - Air Market"
description: "You have attached a custom code tool to an AI agent, and it either errors about the output type or the agent ignores it entirely. This covers writing that tool properly, which is not the same as writ…"
canonical: "https://airmarket.ai/app/n8n-code-tool"
---

[Air Market](/) / [Automation](/category/automation) / n8n Custom Code Tool

Skill by [Romuald Członkowski](/@czlonkowski)

# n8n Custom Code Tool

Make the code tool your AI agent will actually call

## What this does

You have attached a custom code tool to an AI agent, and it either errors about the output type or the agent ignores it entirely. This covers writing that tool properly, which is not the same as writing a normal code step. Reach for it when the code you are writing is something an AI will call.

### Top 3 things it does for you

- Write a Code Tool an agent can invoke
- Read the query the agent passes in
- Define an input schema for structured arguments

## Information

**n8n Custom Code Tool at a glance**

|  |  |
| --- | --- |
| Kind | Skill |
| Publisher | [Romuald Członkowski](/@czlonkowski) |
| Category | [Automation](/category/automation) |
| Works with | Agent Skills - an open standard supported by 40+ agents |
| Size | 36 KB |
| Licence | MIT |
| Repository | [czlonkowski/n8n-skills](https://github.com/czlonkowski/n8n-skills/tree/9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25/skills/n8n-code-tool) |
| GitHub stars | 6,119 (as of Nov 2026) |
| Installs | 1,833, counted by skills.sh (Nov 2026) |

## Security report

**Verified.** AIR scanned this exact version of n8n Custom Code Tool and flagged nothing. AIR's verdict: **safe**.

**What n8n Custom Code Tool's check was run against**

|  |  |
| --- | --- |
| Commit | 9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25 |
| Content hash | 74b5613f7bd17bf6a3c851efa36b2eb289101035ce2a7e62ff339ee8cd48c455 |
| Files read | [Browse the files at this exact commit](https://github.com/czlonkowski/n8n-skills/blob/9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25/skills/n8n-code-tool/SKILL.md) |

A scan is named by the exact content it read, not by a version number. A different version is a different artifact, and nothing here applies to a version AIR has not scanned.

[Read the full security report for n8n Custom Code Tool](/security/n8n-code-tool)

## About n8n Custom Code Tool

This is for writing JavaScript or Python in the n8n Custom Code Tool, the tool an AI agent can call. It is not the workflow Code node, and the difference matters.

Use it when building a Code Tool attached to an AI Agent, writing code an LLM will invoke, parsing the query input, returning a string result, defining an input schema for structured arguments, or troubleshooting errors about the wrong output type, missing execution data, a response that should be a string but is an object, a read-only name property, or an agent that simply will not call the tool.

It covers the critical differences between the Code node and the Code Tool: the return format, the helpers and variables that are unavailable in the Code Tool sandbox, the naming rules that let an AI invoke it, and when a sub-workflow tool or an HTTP request tool is the better choice.

## What's inside

- SKILL.md - instructions
- ERROR_PATTERNS.md - reference
- INPUT_SCHEMA.md - reference
- README.md - reference

## Questions

### Is n8n Custom Code Tool safe to install?

AIR scanned this exact version of n8n Custom Code Tool and flagged nothing. AIR's verdict: safe. The verdict is named by the content that was read, at commit 9ea3aa58cff2, so it cannot drift onto a version nobody scanned. The full report is at https://airmarket.ai/security/n8n-code-tool.

### How do I install n8n Custom Code Tool?

Open https://airmarket.ai/app/n8n-code-tool on Air Market and use the install action: Air Market hands Claude a prompt naming this exact skill, and Claude sets it up. Source, pinned to the exact commit this listing describes: https://github.com/czlonkowski/n8n-skills/tree/9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25/skills/n8n-code-tool. Install from that link, not the branch.

## Related on Air Market

- [More Automation listings](/category/automation)
- [Everything by Romuald Członkowski](/@czlonkowski)

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Canonical URL: <https://airmarket.ai/app/n8n-code-tool>