Category: chain-agnostic chain-identifier standard / namespace control plane / multi-chain interoperability primitive
Summary: CAIP-2 is the base chain-naming layer for chain-agnostic crypto plumbing. It standardizes a compact namespace:reference identifier, then pushes real meaning into namespace-specific resolution rules. That keeps the syntax small, but it also means namespace maintainers quietly sit inside the interoperability control plane.
What it does:
Defines a case-sensitive chain_id format as namespace:reference
Lets a short namespace identify a family of chains or a resolution standard such as eip155, bip122, or cosmos
Keeps the base syntax small enough for onchain storage, hardware-wallet display, filenames on case-sensitive systems, and URL paths
Delegates the detailed semantics of each namespace and reference format to separate namespace specifications
Gives multi-chain apps, wallets, and standards a common way to refer to chains outside a single ecosystem-specific ID system
Key claims:
The important move is not merely cross-chain naming; it is governance by namespace. CAIP-2 says a global identifier exists only because each namespace points to some further resolution method, which means namespace maintainers quietly become part of the control surface for chain-agnostic interoperability.
The rationale section makes the design tradeoff clear: the format is intentionally constrained for portability across URLs, hardware-wallet screens, and onchain or transaction-adjacent contexts. So CAIP-2 is infrastructure for machine-readable trust boundaries, not just developer ergonomics.
The test cases are analytically useful because they span Ethereum, Bitcoin, Cosmos, StarkNet, and Lisk. That breadth shows CAIP-2’s role as a lowest-common-denominator coordination layer across ecosystems that otherwise use incompatible native identifiers.
Because later standards like CAIP-10 and CAIP-25 embed CAIP-2 identifiers, control over chain naming propagates upward into account identification, wallet-session scopes, and capability negotiation. A lot of later wallet-auth standardization inherits this foundation instead of replacing it.
The spec belongs in the active corpus because it helps separate three layers that often get flattened together: chain naming, subject naming, and session authorization. CAIP-2 only solves the first layer, but later standards depend on it.
Whitepaper: No standalone CAIP-2 whitepaper or litepaper surfaced in this pass. The clearest primary materials were the official CAIP-2 text, the raw CAIP markdown, and the Chain Agnostic CAIPs repository; see ../../whitepapers/caip-2-primary-sources-2026-05-10.md.