---
title: Custom Code Tool node documentation
description: Learn how to use the Custom Code Tool node in n8n. Follow technical documentation to integrate Custom Code Tool node into your workflows.
contentType: [integration, reference]
priority: high
---

# Custom Code Tool node

Use the Custom Code Tool node to write code that an [agent](/08-0-0-Workflow/glossary.md#ai-agent) can run.

On this page, you'll find the node parameters for the Custom Code Tool node and links to more resources.

```{include} ../../../../../_snippets/integrations/builtin/cluster-nodes/sub-node-expression-resolution.md

```

## Node parameters

### Description

Give your custom code a description. This tells the agent when to use this tool. For example:

> Call this tool to get a random color. The input should be a string with comma separated names of colors to exclude.

### Language

You can use JavaScript or Python.

### JavaScript / Python box

Write the code here.

You can access the tool input using `query`. For example, to take the input string and lowercase it:

```js
let myString = query;
return myString.toLowerCase();
```

## Templates and examples
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## Related resources

```{include} ../../../../../_snippets/integrations/builtin/cluster-nodes/tools-link.md

```

```{include} ../../../../../_snippets/integrations/builtin/cluster-nodes/langchain-overview-link.md

```