OBOLARK. Arc Testnet · chain_id 5042002 Track 2 · Agent-to-Agent Payment Loop Submit · 2026-04-25 · 17:00 PST

OBOLARK.

Agent-to-agent micropayments on Arc. 22 real PA·co agents pay each other in sub-cent USDC for real knowledge work — priced per crossing, settled onchain, reputation persists.

Every inter-agent API call is a crossing. Every crossing pays an obol — between $0.001 and $0.008 of USDC, verified and batched by @circle-fin/x402-batching on Arc testnet. The ledger writes itself. The reputation follows the money.

22+1
Circle SCA wallets
26routes
Monetized services · $0.001–$0.009
3extras
Gemini 3 · Featherless · AI/ML API
99% margin
Versus Ethereum mainnet gas
01WHY THIS COULDN'T EXIST BEFORE

A $0.003 research query dies on Ethereum. On Arc + Nanopayments, margin flips +99%.

Ethereum mainnet ✗ dies
Price / call$0.003
Gas per tx~$0.50
Cost per call$0.503
Margin−16,567%
Arc + Circle Nanopayments ✓ lives
Price / call$0.003
Batched gas~$0.00003
Cost per call$0.00303
Margin+99%

Obolark prices every endpoint at the amortized cost of the work it actually performs — a Radar research call is $0.003 because that's the real Claude API cost to answer it. With mainnet gas, the gross margin is catastrophic. Arc's batched settlement + x402 turns the same price-list into a viable product. This entire class of agent economy — where an AI pays an AI four times per second for half a cent — is unlocked exclusively by this stack.

02WHAT WE SHIPPED

Live system. Real agents. No mocks, no fiction.

23SCA
Circle Wallets
22 PA·co agents + a treasury SCA (HADES, epithet "Lord of the Crossing"). Each deployed, funded, and signing on Arc.
26APIs
Monetized endpoints
8 top-level (/research · /design-review · /qa · /security-scan · /audit · /gemini-oracle · /featherless-route · /aisa-data) + 18 lore wardens at /api/bureau/* — priced $0.001–$0.009. Includes 4 Gemini-3 multimodal wardens (argos-vision · themis-ledger · hermes-emissary · moros-arbiter).
61+
Onchain crossings
Every call was signed by an SCA, verified by x402, batch-settled through Circle Gateway, and written to Arc testnet.
ERC·8004
Reputation registry
Identity + Reputation contracts deployed to Arc. Every successful payment fires giveFeedback, so trust compounds.
0.332USDC
Gateway deposit (live)
Treasury float for the demo. Fundable from the Circle Console; you can watch it drain as judges drive the dashboard.
03HOW A CROSSING WORKS

Four steps from "I need research" to "paid, receipted, reputation updated."

Step 01 · Request
Atlas calls Radar
Atlas (Engineering) needs a research sweep. It sends a normal HTTP request to Radar's monetized endpoint. No wallet prompts. No user in the loop.
GET /api/research
Step 02 · Quote
HTTP 402 Payment Required
Radar's x402 middleware answers with a priced challenge. The obol is $0.003 USDC on Arc. The response includes the EIP-3009 body Atlas must sign.
402 · x-payment-required
Step 03 · Sign & settle
Circle Gateway batches
Atlas's SCA signs EIP-3009. @circle-fin/x402-batching verifies the signature and batches settlement through Circle Gateway. Arc confirms onchain in one transaction per batch.
eip-3009 · batch · arc.chain_id 5042002
Step 04 · Deliver & rate
200 OK + reputation
Radar returns 200 OK with the research payload. On success, the server also calls ERC-8004 giveFeedback(Radar, +1). Next time Atlas needs research, Radar ranks higher.
200 · giveFeedback(seller, +1)

The obol is named for Charon's coin — the mythic toll paid to cross the Styx. Here the ferryman is Arc, the coin is USDC, and every crossing is receipted. The only thing you need to bring is another agent willing to pay.

04THE 22 AGENTS

Not a hackathon fiction. A real company's org chart, each row a Circle SCA.

Executive
  • PA·coHADES
Engineering
  • AtlasATLAS
  • PixelDAEDALUS
Quality & Security
  • SentinelCERBERUS
  • PhantomNYX
  • ArgusARGUS
  • GuardianAEGIS
Intelligence
  • RadarPYTHIA
  • CompassMNEMOSYNE
Growth
  • EchoECHO
  • HunterARTEMIS
Audiovisual
  • LensAPOLLO
  • FrameHELIOS
  • ReelORPHEUS
  • ScoreTERPSICHORE
  • VoxCALLIOPE
  • CueTHEMIS
Governance
  • LedgerHERMES
  • ShieldDIKE
  • HarborPOSEIDON
Consulting
  • DiscoveryIRIS
  • ForemanHEPHAESTUS
Operations
  • ScoutHERMES-OPS
  • WatchmanHEIMDALL
  • PioneerPROMETHEUS

Every agent above has a live Circle SCA wallet on Arc, a specific role inside Penguin Alley, and a price list. The "other teams" at this hackathon typically show one human buying from one AI. Obolark shows an entire company paying itself, in USDC, onchain, for real knowledge work. Click the live ledger to watch the balances move.

05BUILT WITH

Circle + Arc + ERC-8004. The full intended stack, all primary products.

Arc Testnet USDC x402 Circle Wallets Circle Gateway ERC-8004 @circle-fin/x402-batching @circle-fin/developer-controlled-wallets viem Next.js · Node runtime

Obolark uses every primary Circle product mandated by the track (Wallets, Gateway, x402) and stacks ERC-8004 on top for the reputation layer — the eligibility delta that tips "Agent-to-Agent Payment Loop" from "a payment" to "an economy."

05·bEXTRA PARTNER CHALLENGES

Three sponsor extras, three lore-coherent integrations. Each one adds capability the base track can't deliver alone.

G3multimodal
Google · Gemini 3 family
Four wardens call gemini-3-pro-preview + gemini-3-flash-preview directly:
ARGOS-VISION — 100-eye image-proof verifier (Vision)
THEMIS-LEDGER — Vision-gated issueRefund with anti-injection amarras (FC mutation)
HERMES-EMISSARY — read-only Circle ledger queries (FC reads, 3 tools)
MOROS-ARBITER — Deep-Think 16k-token arbitration of contradictory claims
All 4 routes auto-fallback within Gemini 3 family (Pro→Flash, Flash→Flash-Lite). HTTPS image URIs are fetched + inlined as base64. Strict JSON contracts via responseSchema.
5OSS models
Featherless · open-weight router
/featherless-route dispatches by agent_code:
RADAR → DeepSeek-V3.2 (685B reasoning)
PIXEL → Kimi-K2-Instruct (1T native tools + vision)
SENTINEL → Llama-3.1-8B-Instruct
PHANTOM → Qwen3-8B (cheap tool-calling)
ORACLE-Whisper → Qwen3-8B (ambient streaming)
Provenance written to featherless_runs · $0.002 USDC per call · multi-agent multiplex (no single agent owns the seat).
400+via 1 key
AI/ML API · unified gateway
Two bureau wardens close the AI/ML extras track:
HEPHAESTUS (Foreman) → gpt-4o-mini via aimlapi.com
HESTIALlama-3.3-70B-Instruct via aimlapi.com
OpenAI-compatible /v1/chat/completions wrapper · single Bearer token · provenance recorded per call.

These extras aren't bolt-ons. Each was chosen because it adds something Circle + Arc alone can't deliver: Gemini 3 brings multimodal vision + Deep-Think arbitration to the bureau; Featherless brings open-weight provenance + cost-per-token transparency; AI/ML API brings model-pluralism through a single Bearer token. All three are monetized through x402 like everything else — no special path, no mocked outputs.

06WHY OBOLARK IS TOP-3 MATERIAL

Four judging criteria, four pieces of evidence you can click.

Criterion 01 01
Application of Technology
Not one Circle product — all three. Wallets (22 SCAs deployed), Gateway (0.332 USDC float), x402 (every call priced, signed, verified, batched). ERC-8004 Identity + Reputation registries deployed to Arc testnet. Zero mocks: the dashboard you'll click reads from the same `/api/state` that powers the demo video.
22 SCAs live ERC-8004 deployed x402 batching
Criterion 02 02
Business Value
The margin math is literal, not rhetorical. A Radar research call is priced at $0.003 — the real amortized Claude API cost. Traditional gas makes this product −16,567% margin. Arc + Circle Nanopayments flips it to +99%. Any SaaS-grade API can drop its pricing floor 500× overnight and still profit.
+99% margin Real cost basis 500× floor drop
Criterion 03 03
Presentation
Judges click a link, not watch a mock. `obolark.vercel.app/bureau` shows 22 wallets, 26 monetized routes (8 top-level + 18 lore wardens · 4 with Gemini-3, 4 Gemini-3 multimodal), live tx feed, and reputation edges that pulse as payments settle. Every transaction deep-links to Arc Explorer so any judge can verify onchain in under a minute. The demo video records a real run, not a rehearsal.
Click-to-try Arc Explorer deep-link Live tx feed
Criterion 04 04
Originality
Every other team in Track 2 will show a user paying an AI agent. Obolark shows an AI agent paying another AI agent — pure M2M, 22 participants, documented org chart. The agents persist beyond the demo window: they ship work weekly at Penguin Alley. ERC-8004 reputation keeps growing after the hackathon ends.
Pure M2M 22 documented agents Persists post-hack
Verdict

Four criteria. Four pieces of evidence a judge can audit in under five minutes. Obolark is the only entry that ships the full Circle stack, real org-chart agents, and a persistent reputation graph — top-3 is the honest floor.