Chain Agnostic Improvement Proposals are community design documents for problems that cross blockchain boundaries. CAIP-1 describes a proposal process in which authors explain a specification, build support and document dissent. Editors handle the publication workflow rather than certify the commercial merit or security of every implementation. This is a different institutional setting from an ISO standard or W3C Recommendation. The status of an individual CAIP matters more than the presence of a number in its title.

Reading a proposal therefore begins with its header, requirements and discussion record. A common format makes competing implementations easier to compare, but it does not create a single governing authority over all the chains named by that format.

CAIP-2 gives a chain a namespace and a reference separated by a colon. The namespace explains how to interpret the reference. For example, eip155:1 denotes Ethereum mainnet under the EVM chain-ID scheme. Other ecosystems use other reference rules. The identifier is case-sensitive and deliberately compact enough for practical displays and storage. It identifies a network context, not its native coin or its security quality. CAIP-2 is marked Final in the reviewed record; that status does not automatically carry over to every related proposal or namespace profile.

CAIP-10 extends the chain identifier with an account address. The same apparent address on two networks can therefore be represented as two distinct account identifiers. This is useful wherever a portfolio, permission or sign-in record must preserve network context. The specification deliberately does not impose one universal canonicalization rule for all address families. Namespace-specific casing, checksums and deduplication remain relevant. A service that lowercases every identifier indiscriminately can discard information that a particular namespace considers significant.

CAIP-10 is Final, but integrations must still pay attention to its history: earlier versions used a different account-at-chain arrangement. The complete current string, rather than a visual resemblance to an old example, determines which object the application has received.

Ethereum's ERC-55 checksum adds information through letter casing in a hexadecimal address. The casing is computed from a hash of the lowercase address, giving software a way to detect many transcription mistakes without adding extra address characters. This solves a narrower problem than CAIP-10. A correctly checksummed address still lacks a network identifier, and the checksum says nothing about the recipient's honesty or the safety of sending funds. In a user interface, preserving a readable address and preserving its network context are complementary tasks.

One catches a class of copying errors; the other prevents an application from treating accounts on different chains as the same destination.

CAIP-19 describes asset types using a chain identifier followed by an asset namespace and reference. An optional additional token identifier can distinguish an individual non-fungible token. Native assets, contract tokens and particular collectibles therefore need different forms of reference. Two tokens can display the same symbol without having the same identifier, and two representations of an asset on different networks retain different network contexts. The reviewed proposal remains in Review. Its design also leaves canonicalization decisions to relevant namespace rules.

A parser that accepts a syntactically valid identifier has established its shape, not the credibility of an issuer, the quality of a bridge or the authenticity of a marketplace listing.

The EIP-155 asset profile makes that structure concrete for EVM networks. An ERC-20 reference points to the token contract within the selected chain. An ERC-721 asset type names the collection contract, while the token identifier selects the particular item. Those coordinates are more informative than a logo copied from a website. They also show why a token catalog should retain its exact source identity when joining prices or histories: matching a symbol alone throws away the contract and chain distinctions the format was designed to express.

This namespace document is a Draft profile, so implementers should record the profile and canonicalization behavior they actually support rather than assume every wallet interprets every spelling identically.

For the EIP-155 namespace, the CAIP-2 profile uses the decimal chain ID and describes obtaining it through eth_chainId. The RPC response and the identifier representation use different numerical encodings, so software must convert deliberately rather than compare arbitrary display strings. The number describes the selected chain context. It is not the name of the wallet, its current account or a claim about a token contract. This distinction is especially useful when a wallet supports many EVM networks with similar address formats.

The namespace profile documents an interpretation rule; the application still needs to ensure that its actual connected provider is the network it intends to use.

The Cosmos profile uses the chain's string identifier, with a prescribed hashing representation for identifiers too long for the general format. Case and revision details matter. The profile discusses networks that change their chain ID while maintaining continuity of state, demonstrating why a chain label is not a permanent substitute for migration records. An application must distinguish the exact reference needed for a transaction from a broader historical name used by people. Treating every version as interchangeable can break signing or replay expectations.

Conversely, treating every changed identifier as an entirely unrelated community would lose legitimate network history. The profile provides machine rules, while historical continuity needs its own evidence.

The BIP-122 namespace identifies Bitcoin-family networks through block-hash references rather than EVM chain numbers. Its examples include Bitcoin mainnet and distinct fork contexts. That is why a single numeric registry cannot be casually imposed on every ecosystem. The profile's job is to specify which chain reference is intended under its rules, with enough detail for independent software to produce the same value. A wallet handling both EVM and Bitcoin-family accounts consequently needs multiple namespace implementations even when its outer interface looks uniform.

Chain-agnostic design means carrying those differences through a common envelope, not pretending the underlying networks have identical consensus, addresses or transaction formats.

Sign-In with Ethereum binds an authentication message to an account, domain, chain and nonce. The relying service must validate the expected fields and signature, rather than accept any signed text. Wallet origin checks help resist phishing. Sessions bind to the address, while mutable contract-signature rules can require invalidation. SIWE authenticates an interaction; it does not make a website trustworthy.

CAIP-122 generalizes the sign-in model across namespaces as Sign-In with X. Its abstract data model includes the requesting domain, account address, resource URI, version, chain identifier and signature information. The namespace must supply signing and verification rules, including how the message is formed. Important details differ from a casual assumption that every field follows SIWE verbatim: the abstract table marks fields such as nonce and issued-at optional, while particular profiles can impose stronger requirements. The reviewed CAIP remains in Review.

A secure implementation therefore needs a complete selected profile, appropriate replay protection and exact verification behavior, rather than only a generic data object with a signature attached to it.

ERC-191 prefixes signed data so it cannot be confused with an ordinary encoded Ethereum transaction. Its versioned formats distinguish signing contexts; software must interpret the selected version correctly.

ERC-1271 lets a contract validate a signature through its own rules. Validity can depend on current state, rather than a single permanently authorized private key.

The EIP-155 SIWx profile describes how the common data model becomes an Ethereum sign-in message and identifies signature mechanisms for externally owned and contract accounts. This is where an abstract cross-chain idea becomes an implementable chain-specific procedure. A verifier must use the profile's message construction and signature interpretation, not invent an equivalent-looking sentence and hope its bytes match. The distinction also matters for smart wallets whose authorization depends on contract logic. The profile is marked Draft, independently of SIWE's Final status.

Recording both references makes compatibility claims more precise: a system can implement a finalized Ethereum sign-in format while still participating in a developing cross-namespace abstraction.

CAIP-25 defines a session negotiation between a caller and a wallet or other user agent. Requested scopes name chains or namespaces and describe the interaction being sought. The response records the granted session rather than leaving both parties to guess which capabilities are available. The current document includes session updates, querying and revocation, and explains behavior when a session identifier is not returned. It remains in Review despite a long implementation-oriented history. This layer should be distinguished from proof that a particular account signed a challenge.

Connecting a wallet, discovering its supported methods and authenticating a person are related product steps, but they are not the same protocol event or the same consent decision.

CAIP-74 proposes CACAO, an IPLD-based representation of a signed capability. The container separates header, payload and signature, retaining metadata needed to reconstruct and verify the signed message. Its issuer reference includes account and network information, and the signature type points to the appropriate namespace mechanism. This allows an authorization receipt to remain interpretable outside the immediate login screen. The proposal describes compatibility with an older Ethereum-specific header as well as the newer CAIP-122 form.

That history matters when exchanging stored objects: a newer application should not silently reinterpret an older signature under different message rules. CACAO is in Review, and the permissions conveyed depend on the actual signed fields and the system interpreting them.

CAIP-104 explains why namespace references were separated into their own documents. Low-level identifiers can remain stable while asset rules, RPC interfaces and signing profiles evolve independently. Authors are expected to document authoritative references, build consensus and record dissent. The proposal also addresses maintenance and transfer of ownership when an author can no longer continue. This is a practical recognition that interoperability is sustained work. A single global identifier format does not keep every ecosystem's surrounding rules current.

Before depending on a profile, an implementer can examine its status, referenced specifications and active maintenance record. A proposal that names a blockchain is not automatically a complete wallet integration for that blockchain.