Circle Arc Network: ChainGraph Workflow Guide

Arc is Circle's EVM-compatible Layer 1 blockchain, purpose-built for financial use cases. It uses USDC as the native gas token, so agents and users never need ETH on Arc. Consensus is Malachite BFT with ~350ms finality. Public testnet launched Oct 2025; mainnet expected 2026.

Arc's key primitives: Circle Payments Network (CPN) for global USDC settlement corridors, StableFX for 24/7 on-chain FX (atomic Payment-versus-Payment, PFMI P12 compliant), xReserve for on-chain USDC/USYC reserve management, ERC-4337 Paymaster for USDC-as-gas account abstraction, and CCTP v2 for cross-chain USDC bridging (13 domains, Fast Transfer ~30s). USYC (Hashnote, US T-bill backed) is Circle's first native yield-bearing asset on Arc.

Run ART-42 first. Its scores route you to one or more of the seven downstream chains. The CCTP v2 branch activates automatically when ≥2 dimensions score >0, indicating cross-chain flows are needed.

Circle's post names x402 and MPP (Machine Payments Protocol) as the "value-transfer protocol" layer of the open agentic economy, with settlement in stablecoins, principally USDC, and says Arc "will carry them from day one" alongside the identity and reputation registries covered below. We do not run on Arc or settle anything ourselves; the nodes below are offline verifiers that check the shape of an x402/MPP flow against its own wire format, not a live payment.

Circle's post draws a line between payment volume and payment finality: "onchain settlement proves that a transaction occurred and can contribute useful evidence, but payment volume alone does not prove quality and can be manipulated." art-492, the settlement finality classifier, is the node that makes that distinction concrete: it sorts a settlement into one of three ordered finality tiers rather than treating any onchain reference as proof of completion. See the Agentic Commerce chain for how Paymaster gas abstraction and CPN settlement compose for autonomous Arc agent payments.

ERC-8004 defines three registries: Identity (agentId + agentURI), Reputation, and Validation. Circle's post states these "have live implementations on public chains, and Arc will carry them from day one." None of our nodes read any of these registries onchain; each checks caller-supplied data against the registry's own schema or against an independent attestation scheme.

Circle operates the Agent Marketplace, a curated catalog and public discovery API that the same post describes as having "more than 900 paid services," and names as "today's curated catalog, the seed from which an open index and ranking can grow." We are not listed in it, have no roadmap to be listed, and do not build or operate any discovery or ranking surface ourselves.

Circle's post names "verifiable compute, including trusted execution environments," as one input to agent validation. We ship the first half and not the second: 97% of our live deterministic nodes (605 of 619, re-derived from chaingraph.json on every build) carry a real risc0 groth16-bn254 zero-knowledge proof that the published output came from the published kernel, independently replayable offline by anyone. We do not run or attest to any trusted execution environment; TEE-based attestation is outside our scope.

All Arc tools cite primary-source regulatory material. No fabricated figures. All numerical estimates (CPN fee, Arc gas price, StableFX spread) are clearly labeled as estimates and user-adjustable.

Every Arc tool produces an OpenChainGraph §4 artifact: a JSON document anchored by a WebCrypto SHA-256 execution_hash over the sorted-key canonical preimage of policy_parameters + output_payload. The hash is independently verifiable by any tool that re-runs the same inputs.