@integraledger/lcp-binding-evm-common

Shared EVM machinery for the rail bindings: typed-data construction, signature verification, and event decoding. This is not itself a rail binding — it is what @integraledger/lcp-binding-evm-x402, @integraledger/lcp-binding-evm-escrow and @integraledger/lcp-binding-evm-mpp are built from.

npm install @integraledger/lcp-binding-evm-common

Acceptance signatures

Implements the SignatureVerifier port that @integraledger/lcp-authority declares, across four schemes:

| Scheme | How it verifies | |---|---| | eip191 | Recovered offline — no chain access | | eip712 | Recovered offline — no chain access | | erc1271 | On-chain, through an injected viem client | | erc6492 | On-chain — counterfactual accounts not yet deployed |

The EOA schemes need no network, which is what lets the deterministic conformance vectors cover them.

import {
  type AcceptanceSignatureInput,
  type AcceptanceVerifyOpts,
  verifyAcceptanceSignature,
} from "@integraledger/lcp-binding-evm-common";

declare const acceptance: AcceptanceSignatureInput; // scheme: "eip191" | "eip712" | …
declare const smartAccountOpts: AcceptanceVerifyOpts; // { chainId, client } — a viem PublicClient

// EOA schemes need no network at all — no client, no chain id.
const ok = await verifyAcceptanceSignature(acceptance);

// The smart-account schemes do, and an absent client THROWS rather than answering `false`:
// "not verified" and "verified as forged" are different facts.
const onChain = await verifyAcceptanceSignature(acceptance, smartAccountOpts);

Three outcomes, kept distinct

A malformed configuration throws — an absent chain id or a missing client is an integration error the caller must fix. A malformed record throws — an unparseable timestamp is a different fact from a forged signature, and letting it hide behind a bad-signature verdict would lose that. A malformed signature returns false — recovery over forged bytes fails deep in curve math, and a verifier that crashes on a forgery cannot report the forgery.

Collapsing any two of those into one another is how a verifier ends up reporting the wrong thing about the one case it exists for.

Requirement ids

This package's source and its messages cite short ids — ATA-3, RCS-5, CMP-6 and their kin. They are not LCP clause numbers. LCP is cited by section (§8.3.1, §C.2); anything shaped XXX-n comes from Integra's functional specification of what a complete agent transaction requires, the fourteen families below. Nothing in this package's behaviour depends on them, and where an id and an LCP section disagree the section governs.

| | | | | |---|---|---|---| | IDN identity | ASP authority to spend | ATA authority to accept terms | TRM the terms record | | RCS recourse | PAY payment and settlement | WLD the transactional weld | OFR offer integrity | | FRC fraud, risk, and compliance | OPS commercial operations | DSC discovery and reputation | ORC orchestration | | CMP composition | PRS persistence and verification infrastructure | | |

Requires Node >= 24. Part of the Legal Context Protocol open layer — see the documentation and the package index. Apache-2.0.