Summary
mistralai/mistral-medium-3 on Vertex AI's rawPredict endpoint does not accept PDF documents, despite mistralai/mistral-ocr-2505 supporting
them on the same endpoint. Sending a PDF via document_url returns a misleading 404 Not Found instead of a proper error or successful
processing.
Current Behavior
Sending a PDF as document_url in the message content:
{
"model": "mistral-medium-3",
"messages": [{
"role": "user",
"content": [
{"type": "text", "text": "extract invoice number"},
{"type": "document_url", "document_url": "data:application/pdf;base64,<base64>"}
]
}]
}
Result: HTTP 404 Not Found — {'detail': 'Not Found'}
Using image_url with a PDF mime type returns HTTP 400:
"Image content must be a URL (starting with 'https') or base64 encoded image (starting with 'data:image/;base64,...')"
Expected Behavior
mistral-medium-3 should either:
- Accept PDF input directly via document_url (like mistral-ocr-2505 does), or
- Return a clear 400 Bad Request with a message like "document_url is not supported for this model" — not a 404
Summary
mistralai/mistral-medium-3 on Vertex AI's rawPredict endpoint does not accept PDF documents, despite mistralai/mistral-ocr-2505 supporting
them on the same endpoint. Sending a PDF via document_url returns a misleading 404 Not Found instead of a proper error or successful
processing.
Current Behavior
Sending a PDF as document_url in the message content:
Result: HTTP 404 Not Found — {'detail': 'Not Found'}
Using image_url with a PDF mime type returns HTTP 400:
"Image content must be a URL (starting with 'https') or base64 encoded image (starting with 'data:image/;base64,...')"
Expected Behavior
mistral-medium-3 should either: