COMMON_MISTAKES
Complete catalog of expression errors with explanations and fixes.
- Skills
- Workflow Automation
- 0
What it does and how to use it
A skill that teaches Claude Code to do workflow automation tasks well. It is packaged knowledge the model uses whenever it is relevant.
- Install the skill (command above).
- In Claude Code, describe what you need - the skill turns on by itself when the context fits.
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Install (Claude Code)
mkdir -p .claude/skills/common-mistakes && curl -fsSL https://doutorai.pt/data/lib/skills__common-mistakes.md -o .claude/skills/common-mistakes/SKILL.mdPaste this command into the terminal, in your project folder, and the component installs automatically.
Content
# Common n8n Expression Mistakes
Complete catalog of expression errors with explanations and fixes.
---
## 1. Missing Curly Braces
**Problem**: Expression not recognized, shows as literal text
❌ **Wrong**:
```
$json.email
```
✅ **Correct**:
```
{{$json.email}}
```
**Why it fails**: n8n treats text without {{ }} as a literal string. Expressions must be wrapped to be evaluated.
**How to identify**: Field shows exact text like "$json.email" instead of actual value.
---
## 2. Webhook Body Access
**Problem**: Undefined values when accessing webhook data
❌ **Wrong**:
```
{{$json.name}}
{
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