Models Prompting Formatting Guidelines

Anthropic

• The user role message must be the last message in the conversation history.
• System messages cannot be used alone; they must be accompanied by user messages.
• Examples in the conversation history must always be in pairs of user message followed by assistant message. Deviating from this pattern may cause issues.

OpenAI

• Supports the use of system messages without accompanying user messages.
• Does not require a specific order for user and assistant message examples in the conversation history.

Google

• Does not support the use of a system message without an accompanying user message.
• Requires the user role message to be the last message in the conversation history.