Using curly braces in an ai agent node fails

[Wayne]

I understand that when using curly braces, the ai agents expect some kind of value such as {tools} inline with LangChain, however, I need to give the AI json data which includes the curly braces, in which case it fails, what is the solution?

For exmaple, if I say:

Here’s an example of JSON structure:
{
“name”: “John Doe”,
“age”: 30
}

It will fail, or if I give it a ton of json to analyse, it will fail, even if it’s stringified.

Note this only happens with the system message.

[n8n]

It looks like your topic is missing some important information. Could you provide the following if applicable.

• n8n version:
• Database (default: SQLite):
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app):
• Operating system:

[ria]

Hi @Wayne

You should be able to escape this by using double curly braces.

So in your case:

{{
“name”: “John Doe”,
“age”: 30
}}

[Wayne]

Hi Ria,

This isn’t what I’m mean, I don’t think, lets say I want to give an AI Agent an and example json structure, it won’t allow { } as it thinks this is a placeholder for something, and if I use {{ }}, it think I’m going to write an expression.

So I have no way to give it a json exmaple.

The only workaround I’ve found is to use the memory manager to insert the system message as it won’t work in the AI Agent node when adding a system message.

[ria]

Hi @Wayne,

Not knowing what your exact use case is, but perhaps you could use two agents (either chained or use the sub-workflow tool) to have the other agent do the structuring with the Output Parser Node ?

Structured Output Parser node documentation | n8n Docs

Otherwise, feel free to raise this as a feature request here: Feature Requests - n8n Community

[Wayne]

The issues I’m having is the structured output parser is failing, to I want to give it my own prompt which i know work, but I need to specify the json I want with an example in the system message, but it wont let me.

I also want to provide dynamic json data in the system message, but again, it won’t allow it.

[oleg]

Hi Wayne,

I’d also suggest a tools agent, which has much better support for output parsing. But as Ria said, if you want to use JSON in system messages for a Conversational agent, you’d need to escape curly brackets so something like:

{{ $json.toJsonString().replaceAll('{', '{{').replaceAll('}', '}\}') }}

If you’d use a tools agent, you can just insert JSON directly:

Here’s a small workflow showing both approaches:

Hope that helps!

Oleg

[Wayne]

Ahh thanks! I didn’t realise it worked in a tool agents but not a convo agent! Good to know, thanks for the info Oleg