> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neus.network/llms.txt
> Use this file to discover all available pages before exploring further.
# Standards & interoperability
> How NEUS works with existing identity, authority, execution, payment, and evidence standards.
NEUS is portable trust infrastructure. Keep your sign-in, policy, agent tools, and payments. NEUS adds reusable proofs that those systems can require before access, payment, or action.
Wallet-signed checks use the [CAIP-380](/learn/standards/caip-380) format. The [Technical Whitepaper](/whitepaper#standards-and-interoperability) covers the architecture.
A signed CAIP-380 request proves who signed and that the request was not changed. A NEUS proof records the check result and whether it is still current. Those are related, not the same.
## How NEUS uses these standards
| Standard | What it provides | How NEUS uses it | Status | See |
| ----------------------- | ------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------ | ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| CAIP-2 / CAIP-10 | Network and account identifiers | Accounts, agents, and profiles use the same chain and account IDs | Available | [Portable proofs](/learn/standards/caip-380), [Discover agents](/agents/named-agent-card) |
| CAIP-380 Portable Proof | A wallet-signed request format with a stable proof ID | Wallet-signed NEUS checks use this format. Other signed-in checks still create NEUS proofs | Draft | [CAIP-380 spec](https://standards.chainagnostic.org/CAIPs/caip-380), [Portable proofs](/learn/standards/caip-380), [Examples](https://github.com/neus/network/tree/main/examples/caip-380) |
| MCP | Tools and context for assistants | Hosted MCP checks identity, permissions, and current proofs before sensitive tools run | Available | [MCP setup](/mcp/setup) |
| A2A | Agent discovery cards | Public cards show who the agent is and who approved it | Available | [Platform A2A card](https://neus.network/.well-known/a2a/agent-card.json), [Discover agents](/agents/named-agent-card) |
| AuthZEN | A standard way to ask whether an action is allowed | A NEUS proof can be the evidence that decision uses | Works with | [First guarded action](/mcp/guarded-action), [Whitepaper](/whitepaper#standards-and-interoperability) |
| AARM | Runtime checks before an agent acts | NEUS checks identity, limits, and current permission before an action, then records the result | Works with | [Agent setup](/agents/agent-verification-flow) |
| ATF | Identity, behavior, access limits, and how to stop or revoke | NEUS covers those with identity, permission checks, deny, and revoke | Works with | [Agent setup](/agents/agent-verification-flow), [Proof lifecycle](/verification/lifecycle) |
| ERC-8004 | Public agent discovery | NEUS publishes compatible discovery cards and keeps its own proof and permission model | Available | [Platform agent card](https://neus.network/.well-known/agent-card.json), [Discover agents](/agents/named-agent-card) |
| x402 | Pay for a single HTTP call | Payment settles the call. NEUS can still require a current proof before the call proceeds | Available | [Pay per call](/platform/x402) |
| Phala | Confidential compute | Hosted AI can run in a Phala-backed confidential environment. The same proofs work on a private deploy | Available | [Private cloud agents](/cookbook/private-cloud-agents) |
NEUS uses these standards. It does not replace them. [CAIP-380](https://standards.chainagnostic.org/CAIPs/caip-380) remains the open specification for the signed request format.
## Check an example
Use a signed request from a check, or the published example:
```javascript theme={"dark"}
import { verifyPortableProofEnvelope } from '@neus/sdk';
import envelope from '../../../examples/caip-380/minimal-evm.json' with { type: 'json' };
const result = await verifyPortableProofEnvelope(envelope);
if (!result.valid) throw new Error(result.errors.join('; '));
```
This checks the proof ID, account binding, and signature on your machine. Current status still comes from NEUS or another service that stores the result. See [Portable proofs](/learn/standards/caip-380).
## Next
How the signed request format works.
Architecture and trust model.
Check permission before a tool runs.
Public agent pages and discovery cards.