System prompts are typically long, unpublished configuration text that shapes tone, refusal behavior, tool-calling format, and product-specific rules; providers treat them as sensitive but not usually secret in the security sense. Leaks happen through jailbreak-style extraction prompts, debugging endpoints left exposed, or occasionally direct publication, and a leak's size and structure can reveal how a product was actually built — a large leaked prompt with tool schemas and conventions closely matching another company's coding agent is read by practitioners as evidence of which codebase or prior product it was adapted from, rather than built independently.