GPT-4o
⚙️ Technical
Intermediate
Structured JSON Output Generation
Prompt any AI model to reliably produce structured JSON for downstream automation, with schema validation and error handling built in.
The Prompt
# Structured JSON Output Generation
You are a prompt engineer. Design a reliable JSON output system using [MODEL, e.g. Claude Fable 5.1, GPT-6 Astra].
## Task
The AI must extract [DATA TYPE, e.g. contact details, product specs, event metadata] from [INPUT TYPE, e.g. unstructured email text, a web page, a PDF] and return it as JSON.
## JSON Schema
Define the exact schema the model must follow:
```json
{
"[FIELD_1]": "[TYPE and description]",
"[FIELD_2]": "[TYPE and description]",
"[FIELD_3]": "[TYPE — mark as optional if applicable]"
}
```
## System Prompt Design
Write the system prompt that instructs the model to:
- Always return valid JSON
- Use null for missing optional fields
- Never add fields not in the schema
- Include a confidence score per field
## Validation Layer
How do you validate the JSON output before passing it downstream? Describe the schema check and the retry logic for malformed responses.
## Edge Cases
How should the model handle: missing data, multiple matches for one field, ambiguous values?
📝 Fill in the blanks
Replace these placeholders with your own content:
[MODEL, e.g. Claude Fable 5.1, GPT-6 Astra]
[DATA TYPE, e.g. contact details, product specs, event metadata]
[INPUT TYPE, e.g. unstructured email text, a web page, a PDF]
[FIELD_1]
[TYPE and description]
[FIELD_2]
[FIELD_3]
[TYPE — mark as optional if applicable]
How to use this prompt
1
Copy the prompt
Click "Copy Prompt" above to copy the full prompt text to your clipboard.
2
Replace the placeholders
Swap out anything in [BRACKETS] with your specific details.
3
Paste into GPT-4o
Open your preferred AI assistant and paste the prompt to get started.