HJS Foundation This document specifies the Co-Evolve Binding Protocol (CEP), a lightweight, minimal-structured protocol designed to bind human cognitive evolution with artificial intelligence (AI) evolution. CEP works in conjunction with the Judgment Event Protocol (JEP) and Human Judgment Structure (HJS) as the default collaborative system, while supporting adaptation to other compliant judgment and accountability systems to enhance interoperability and practicality. Leveraging JEP's strengths in standardized judgment recording and lightweight verifiability, HJS's advantages in structured human responsibility management and end-to-end accountability traceability, and the flexibility to adapt to other systems, CEP integrates core advantages to form a complementary three-layer human-AI symbiosis infrastructure. The core goal of CEP is to prevent unilateral AI evolution, maintain human sovereignty in the co-evolution process of humans and AI, and lay the foundation for trustworthy human-AI symbiosis.