CIP stands for CESS Improvement Proposal. A CIP is a design document providing information to the CESS community, or describing a new feature for CESS or its processes or environment. The CIP should provide a concise technical specification of the feature and a rationale for its adoption. The CIP author is responsible for building consensus within the community and documenting dissenting opinions.
We intend CIPs to be the primary mechanisms for proposing new features, for collecting community technical input on an issue, and for documenting the design decisions that have gone into CESS. Because the CIPs are maintained as text files in a versioned repository, their revision history is the historical record of the feature proposal.
However, we also require that, where appropriate, Technical CIPs are also reflected in the protocol's specification, which is the primary source of reference for other developers. The CESS Spec site will in turn point back to the CIPs that have changed some part of the protocol, as well as the CIP's revision history.
For CESS implementers, CIPs are a convenient way to track the progress of their implementation. Ideally, each implementation maintainer would list the CIPs that they have implemented. This will give end users a convenient way to know the current status of a given implementation or library.