GPT-5.3 adds Instant System Card capability for preconfigured prompts

AI Impact Summary

GPT-5.3 now supports an Instant System Card, allowing preconfigured system prompts to be attached to sessions with a single operation. This enables standardized model behavior across applications and reduces the time engineers spend on per-call prompt setup. Security and governance should be reviewed to ensure system prompts comply with policy, and client integrations should be updated to utilize the Instant System Card to realize the automation benefits.