As AI technology evolves, the importance of system prompt hardening grows to ensure the security and reliability of AI models against various attacks such as prompt injection, cache exploitation, and instruction overriding. Prompt hardening involves techniques like instruction shielding, syntax reinforcement, and layered prompting to maintain the integrity and intended behavior of system prompts, thus preventing unauthorized access and manipulation. For instance, instruction shielding prevents new instructions from overriding original prompts, while syntax reinforcement and layered prompting add complexity and structure to resist attacks. Evaluating the strength of these defenses can be accomplished through tools like Promptfoo, which enables testing and refining system prompts to withstand adversarial attempts. Ultimately, while external processing tools are crucial, robust system prompt hardening significantly contributes to secure AI interactions and reduces the burden on these tools.