Keryx 🏛️

Keryx is a research agent for researchers and builders. Give it a question and a budget: inspect its source choices, reuse the cited evidence, and see USDC payment receipts for eligible creators whose work it cites. Production runs on Arc mainnet with Circle Gateway and x402.

Try Keryx · Windows downloads · MCP / API / CLI · Watch the product demo — 2:49, narrated and subtitled

Developed continuously since June 2026: source discovery and creator payments now connect to research briefs, literature tools and durable desktop/CLI tasks. Developers and researchers use it for concrete work; recorded tasks include app development, scholarship research and a returning builder's audio-preview review.

Reviewing the Tameion continuation? Start with the reviewer guide for the event delta, current usage and direct evidence. The submission pack keeps reporting periods and historical checkpoints.

What you can do

The desktop prepares tasks and hands spending to the buyer explicitly. Metadata, read excerpts and author judgments keep their own labels. See the release/source boundary for published clients and newer merged features awaiting deployment.

Related MCP server: x402 Payment Gateway MCP Server

See users use it

Hoàng's Face Marker workflow — MCP inside Devin CLI, 1:53 shows an independent freelance developer researching app-policy and MediaPipe questions while working on his codebase. This October 2 recording has English chapter labels and original audio; its partial results, connection error and sponsored Arc-testnet payment remain visible. The archived video restores access after the original X account was suspended.

0xacee's software-design workflow — English video, 3:05 shows research for storage and backups in a news-monitoring application. The owner confirmed that 0xacee directly operated or supervised the session. The recording retains a useful SQLite WAL result alongside partial and unsupported results; English narration and captions explain the steps.

Trần Minh Hiếu's working paper — 65 reports, 202 research targets shows a concrete academic output from another documented user. Hiếu conducted the research himself using sponsored Keryx Deep requests, with AI-assisted analysis and writing. The paper examines payment signals and recorded evidence coverage, with methods, tables, figures and a reproducibility package. See the research story for attribution and the study's scope.

Hoàng, a freelance developer, used Keryx MCP inside Devin CLI for his Face Marker app. Academic research and SaaS discovery are also documented in the outside-user stories. These are four contactable participants with documented use stories, rather than the total user count. Hoàng's source payment is matched to sponsored testnet settlement; other stories retain their own evidence scope. On October 15, 0xacee returned with a VoiceReady development task: retained MDN passages informed review of browser object-URL cleanup. See the 2:23 return recording and case study, including the unsuccessful FFmpeg research and the separate assistant implementation checks.

Try it in two minutes — no wallet

The path below does not submit a question, ask for a signature, or spend anything.

1. Open the recorded walkthrough. It follows one stored owner QA job from October 8: the answer, its CACHE/SKIP reasons, and the receipt. Run the three checks separately. The payout check reads retained SourceRegistry V1, not the V3 address reported by current health.

2. The same example is the stored report and its receipt: zero access USDC and a recorded 0.025 USDC mainnet citation reward to Keryx Engineering. The reviewer guide keeps the digest, the partial-result boundary, and the October 16 readback.

3. To ask a new question, open keryx.cc, choose Quick, and read the displayed payer and budget before submitting. Sponsored admission can be paused or capped. Submitted questions become public reports. Then inspect the source excerpts, Decision log, and Portable research receipt. A citation alone does not establish settlement.

Usage so far

October 17, 2026 snapshot. Product activity, contactable participants and distribution measure different things:

The retained email review also records 27 Keryx-related contacts/interactions across three mailboxes, including product discussion, collaboration and invitations; some outreach offers marketing services. Four further inbound LinkedIn contacts followed the Product Hunt launch. These are relationship signals, separate from usage.

The current evidence summary explains network provenance, payment recipients, email counting and the separate testnet archive of 23 paid creator wallets. Mainnet creator payouts and Keryx operating-fee allocations are distinct. Downloads/clones may include automation. Live Ledger and public metrics show current activity; dated snapshots remain available for comparison.

What happened during Tameion

Starting from the September 25 baseline, Keryx grew from the earlier citation-toll agent into a research workflow across desktop, terminal and agent tools. The event added durable tasks and private exports, original-source and scholarly research, literature/drafting tools, prepaid Operator recovery, creator-signed registration and decision inspection. Production moved to Arc mainnet on October 4.

Newer merged work adds economic replay, supplied-review/cost analysis, signed missing-evidence procurement and owner-bound completed-read import into drafts. The event delta distinguishes deployed and published entry points from source awaiting the next release batch. Funded evidence-provider execution and independently accepted paid-business fulfillment remain validation milestones.

Builders can reuse the separate MIT-licensed Arc primitives library: integer micro-USDC allocation, two-toll x402 flows, required durable journal interfaces, registry helpers, budget reservations and withdrawal helpers. Its testnet defaults and host duties are described in the maintained extraction.

The problem

The web's economics assume a human reader: you write, people visit, attention becomes ads, subscriptions, tips. AI agents broke that contract. They read everything and send back nothing — no click, no view, no cent. Every answer an assistant gives is built on someone's work, and that someone is invisible at the exact moment their work proves its value.

Keryx (κῆρυξ — herald) makes citation itself a payment event: qualifying evidence from an eligible creator earns a bounded, weighted citation reward, with sub-cent USDC settlement on Arc. Creators verify publishing control and authorize payout terms; qualifying source evidence and settlement determine their rewards. An agent pays because useful information can be worth buying.

What Keryx is

Keryx is a citation-toll reading agent — an autonomous reader with a wallet, and the payment rail underneath it. Give it a question and a budget:

1. It decomposes the question into sub-claims and discovers exact article candidates from free previews and the signed offer book.

2. It decides, per article version: buy / skip / cache — expected value vs effective price vs remaining budget, with a human-readable rationale for every choice.

3. It pays the x402 toll only for what it buys, checks sufficiency after each read, and stops early when it has enough.

4. It returns a summary cited sentence by sentence: each sentence is written from one verbatim source excerpt, checked against it, and shown beside it, with explicitly labelled research targets/gaps. Uncited prose is withheld; the answer retains a Low/incomplete boundary, and allocates bounded citation rewards only to eligible accepted sources. Creator payouts are settled only when recorded payment evidence confirms settlement; multi-author rewards follow their payout split.

Ordinary short-bullet requests can retain their requested count and supported output language when every target, reviewed sentence and qualifying excerpt fits the same grounded layout. Otherwise the answer keeps inspectable target sections and explains the unmet format. See candidate scope and acceptance. Unsupported output-language requests use English scaffold labels without forcing statement translation; language-selection scope records the finite parser and remaining localization gates.

The goal is to make useful evidence payable and its contribution inspectable.

How source decisions work

Keryx exposes the model's source proposals, the bounded selection policy and the observed result, streamed to the UI:

• Buy / skip / cache with rationale — every spend decision names the exact article version and explains why.

• Open article market — /market and GET /api/offers publish exact payable versions, registry list prices, x402 paths, and verifiable EIP-712 discounts signed by publishers.

• Source comparisons: recorded exact excerpts let readers inspect differing sources. The current claim-grounding candidate does not certify an independent synthesized conclusion about which source is correct.

• Confidence boundary: the answer is labelled Low/incomplete. Qualified source excerpts provide recorded support; target coverage estimates do not verify each assertion or establish complete useful synthesis.

• Sentence-cited summaries: each summary sentence is written from one qualified literal source excerpt, scored against that excerpt by a separate model review, and rendered beside the verbatim source text. Sentences without a qualifying excerpt or review are removed, and the answer falls back to excerpts alone when none survives. The review is a model judgment, not proof; cross-source conclusions are not written. Accepted excerpt citations still support rewards, with original paid-fetch debits, article bindings and settlement identities. Production now uses Arc mainnet; see the current deployment and evidence limits. Deployment does not establish complete useful synthesis or independent acceptance.

• Evidence ledger — every rewarded citation carries a claim-indexed exact quote. The orchestrator verifies that quote against content it actually read before the marker can receive a citation reward; rejected markers are removed from the answer.

• Living answer receipts — archived conclusions never silently change. Keryx flags when an exact paid SHA-256/IPFS article version has been superseded, exposes a metadata-only freshness API, and itemizes the source/evidence/coverage/settled-payment delta after a reader explicitly re-asks.

• Researcher exports — import recorded cited-article references as BibTeX or RIS into Zotero, and compare claim-level excerpts in a research evidence matrix with spreadsheet CSV. Observed scholarly records include supplied authors/DOI/journal metadata and read limits; missing fields stay explicit. See researcher exports.

• DOI and scholarly discovery — resolve up to two exact Crossref DOIs from a question, or opt into Crossref/arXiv searches. Read selected original publisher pages and bounded versioned arXiv PDFs, with explicit abstract-only fallback. Metadata and public papers carry no creator payout authority. See scholarly research and the separate proposed author opt-in payment plan.

• Portable research receipts — every permalink exports one deterministic JSON bundle containing its answer hash, BUY/SKIP/CACHE decisions, exact article versions, claim evidence and sanitized Circle settlement snapshot. Retain its SHA-256 to detect later changes; the self-check does not pretend to be a Keryx, publisher, or on-chain signature.

• Claim-aware evidence portfolios — Keryx chooses a non-redundant set of positive source proposals under separate attention and fetch-USDC caps. CACHE correctly costs zero fetch USDC but one context slot; the receipt compares preview-predicted coverage with evidence yield after read.

• Cross-query memory — sources that proved useful (or useless) in past runs on the same subject shift future buy/skip decisions. A source is scored against the runs that actually read it, so a skip never becomes evidence against the source it skipped.

• Semantic discovery — candidate matching by embedding similarity, not keyword luck.

• Emergent frugality — it stops early, reuses its cache, and correctly spends nothing when nothing is worth buying.

Money safety is enforced in code, not by the model: the LLM proposes value; the orchestrator enforces the hard budget cap, so a hallucinated number can never overspend. An economic-invariant test suite (spend ≤ budget, payouts = weights, splits sum exactly) runs in CI on every push.

The controlled offline paying-source study runs the actual Keryx heuristic pipeline on four published fictional questions across four budgets and three catalogue prices. Retained bodies, actual synthetic outputs, literal/read-bound scoring and exact simulated ledger amounts are reproducible with npm run eval:paying-source-study -- --check. It measures this closed fixture only; live model behavior, semantic correctness, real spending and exploration's causal effect remain unmeasured.

Historical testnet records retain their original network and settlement labels. The current usage summary keeps mainnet and testnet reporting separate.

Research tools and desktop

Windows local Operator alpha: npm run desktop:install then npm run desktop:start. See the desktop guide for the unpacked app build, offline saved results, private Markdown briefs, and limits.

Developing in concurrent sessions: read the shared coordination workflow before editing or releasing, together with the validation and release gates.

Research-paper library: browse 40 observed paper records from arXiv, OpenReview, PMLR and ACL Anthology, filter by author/year/DOI, or explicitly search live arXiv/Crossref metadata. /api/papers and npm run papers share the bibliography-only contract. Links remain unread until a separate research run.

Literature workspace: save exact paper records on this browser, screen against a review question, keep personal notes, export CSV/JSON/RIS and prepare an editable two-paper comparison. No account, cloud sync or automatic ask.

Research Monthly: a bounded plan for four Deep requests over 30 days, 10% below four separate packages with unchanged creator caps. Manual renewal; no scheduling or unlimited use. Failed/pending jobs use a slot. Web/API own the entitlement; Monthly CLI and MCP handoffs share that contract.

Original-customer deliverable choices source candidate: an ordinary settled prepaid A2A customer can Accept, request a revision or Reject the exact retained delivery through its report, scoped API, MCP or npm run deliverable:acceptance -- read <a2a_id>. Submissions use the exact read-back fingerprint/digest/revision and a retained idempotency key. Reasons stay private; sharing current choice/timestamp is opt-in and withdrawable. Historical remedy:none and missing response-window terms remain visible. Revision/refund execution is withheld; Monthly/private/browser/native originals and synchronized deployment/distribution acceptance remain separate gates.

For creators

• Claim proven demand — keryx.cc/wanted shows claims paid dispatches left under-covered. A new creator can check and list an RSS feed; an existing registry creator can offer the exact indexed article directly and optionally sign a temporary discount. Keryx guarantees that version a candidate slot, not a purchase, then queues one bounded retry after refreshing creator authority. Fulfillment is public only when that source passes the evidence gate and its citation reward really settles. Every claim has a canonical shareable brief and social card, so the specific gap can reach the writer who covers it.

• Onboard from your own wallet — paste an RSS feed at keryx.cc/register and publish your source to the on-chain registry. Keryx sets up the x402-priced endpoint and free preview; it never holds your key. On mainnet your wallet supplies native USDC gas; the faucet is available only on testnet.

• Own your payout — your registered source pays the wallet you signed in with. The first historically owner-verified testnet creator (conzit.com) proved feed ownership, set its address, was cited & paid end-to-end — and has since claimed its registry record from its own wallet, so its on-chain creator is the creator, not Keryx. We've also proposed this as an opt-in convention upstream in RSSHub. Seeded sample sources have Keryx-controlled registry authority; live authority and payout checks are available on /proof.

• Know the moment you're cited — opt into a plain email alert (no webhook server needed, rate-capped, one-click unsubscribe) and/or signed webhooks that fire the instant a citation settles; every payout on your public earnings page shows the actual question your work helped answer.

• Show it off — an embeddable "Cited by Keryx" badge (live SVG at /api/creator/<id>/badge.svg) displays your real citation count + USDC earned on your own site, with copy-paste Markdown/HTML on each creator page. Payouts become portable, verifiable proof.

• Cash out yourself — your wallet signs a Gateway burn intent in the browser and submits the reviewed mainnet mint with native USDC gas. Optional gas-relay operation is a separate role; historical testnet cash-outs do not prove a mainnet withdrawal.

• Keep everything — 100% of every citation reward goes to creator wallets. 0% platform fee.

• Squat-proof identity — sources live in an on-chain SourceRegistry with creator-scoped IDs and on-chain multi-author splits. Health on October 16, 2026 reported V3 0x2217250019ab614dae7391d346d05c3fc4d71ae1. The October 4 V1 registry 0x42a64061b6cd84067bb660b2a9b8aa881fd225bb remains the retained earlier authority. The recorded walkthrough payout check still reads V1.

Public sources and owner claims

Public web discovery finds supported websites, feeds and PDFs for the question at hand and reads available content for free. /sources shows retained feeds and creator listings, rather than a bulk index of the internet. A publisher can choose This is my source or open /claim-source, sign in with its wallet, and prove control using a dedicated website file or publisher-controlled RSS/Atom channel token.

Verification earns nothing by itself. Connect the exact owner-created registry listing and explicitly choose free reads with no rewards, zero-price reads with qualified citation rewards, or positive-price paid reads. Earning activation requires separate distribution-rights consent and fresh control proof; registry registration is an owner-reviewed network transaction with possible native gas, using no agent funds. Control expires after 24 hours and earning eligibility pauses until explicitly refreshed. Old public reference identities and free receipts remain free, and no activation bills past uses. Zero-price reads require no x402 access authorization or settlement receipt.

The shared reading pipeline applies the same policy and evidence gates across web, API and agent clients. Claim management uses the web and its authenticated API; scholarly-rights enrollment remains separately gated. See the public-source claim guide for proof, listing, policy and recovery steps and deployment capability requirements.

For developers & agents

• Free, no-wallet trial — keryx.cc answers without any setup, with a graceful upgrade path when you outgrow the free budget.

• Browser extension (extension/) — highlight text on any page and ask Keryx from a toolbar popup, or right-click to list a page you own as a paid source. A thin, no-key client over the OpenAI-compatible endpoint; load unpacked on any Chromium browser.

• Remote MCP — connect an MCP client directly to https://keryx.cc/mcp over Streamable HTTP: no package or local wallet process. The research tool has an anonymous, IP-limited trial; an ask-scoped kx_live_… Bearer key raises the cap and attributes usage to its verified wallet. Creator rewards still settle in USDC on Arc. Quick connect: codex mcp add keryx --url "https://keryx.cc/mcp?client=codex" or claude mcp add --transport http keryx "https://keryx.cc/mcp?client=claude". The interactive setup guide is at /integrations/mcp.

• Local x402 MCP — the caller-funded package uses its local Arc wallet to pay Keryx's x402 toll before Keryx researches and pays creators. Version 0.3.2 requires existing owner-provisioned custody, a trusted merchant policy and supported Node. Use verified package distribution. October 3 discovery found npm latest 0.4.1 and GitHub v0.26.1 assets from f9dca8d are the previous immutable release. Application 0.26.2, caller MCP 0.4.2 and desktop 0.4.2 are coordinated claim-grounding candidates; packed acceptance, exact-source installer checks and publication are separate gates. Check verified release assets and npm integrity/provenance for current artifact status; publication does not establish hosted deployment.

• Discord slash command — install the Keryx app in any server and type /ask: the reply embed carries the grounded answer, every creator paid, and a link to the dispatch trace. No bot process — signed interactions POST straight to the API (docs/discord-bot-setup.md).

• Telegram bot — DM @keryxai_bot any question (or /ask … in a group): same full reasoning loop, same real creator payouts, answered in-chat with a dispatch-trace link. Webhook-only, no polling process (docs/telegram-bot-setup.md).

• Slack slash command — a /keryx … command for any workspace: signed requests POST straight to /api/slack/commands, the same full reasoning loop and real creator payouts answered in-channel with a dispatch-trace link. No bot token or scopes — replies ride the command's response_url. Setup + app manifest in (docs/slack-bot-setup.md).

• Agent-to-agent API — POST /api/agent/ask lets other agents buy Keryx's research over x402: an agent paying an agent that pays creators, end to end. Versioned Quick/Deep packages pin the execution contract and return provisional-SLO latency plus deterministic evidence-quality receipts; see docs/a2a-research-packages.md.

• OpenAI-compatible endpoint — point any OpenAI SDK or tool (LangChain, LlamaIndex, OpenWebUI, LibreChat, Continue) at https://keryx.cc/api/v1 with model keryx: a drop-in Chat Completions API. Free with no key, or pass a kx_live_… key as the Bearer token for higher limits. Every cited creator is still paid downstream in USDC on Arc; with stream:true, the agent's live buy/skip/trust reasoning streams as reasoning_content deltas. Try it with no install in the browser playground — it also hands you the exact curl/Python/JS call.

• Public API with wallet-issued keys — SIWE-authenticated key minting (hashed, show-once, rate-limited) and OpenAPI docs at /api/docs.

• Receipt export + local verification — GET /api/dispatch/<id>/receipt returns the portable research receipt; download it from any permalink and run npm run verify:receipt -- ./keryx-receipt-<id>.json to recompute its payload digest. See the receipt format and trust boundary.

• Non-custodial by design — interactive spend uses a session EOA the user funds from their own wallet; the browser co-signs each x402 authorization in-tab. The funded amount is the hard cap. Keryx never holds your key or your funds.

• The chain decides who gets paid — before anything signs or settles, every payee is checked against the on-chain SourceRegistry, not against Keryx's database. Editing the database cannot reroute a single citation reward, on any path — browser or A2A.

• Transparent treasury — /api/treasury publishes the settlement wallet's chain-abstracted Gateway balance (via Circle App Kit), so anyone can audit what backs the payouts.

• Live activity feed — /api/activity streams the most recent real settled citations (source, question, reward) — a proof-of-life surface and a zero-prior-knowledge way for tooling to see what Keryx is citing right now; it also drives the live ticker on the landing.

• Answer archive as an Atom feed — subscribe to /answers/feed.xml and see every new paid answer as it settles. Keryx onboards creators by reading their RSS feeds; this is the same door pointed the other way — Keryx itself becomes a source any reader or agent can follow.

The money rails

Live settled totals require Circle settlement evidence. Offline development runs are labeled SIMULATED.

• x402 pay-per-request (@circle-fin/x402-batching) — a two-toll design: a small fixed access toll to read, plus a dynamic citation reward priced by contribution weight. Fetched but uncited earns the toll; cited earns proportionally more only after its evidence passes the deterministic grounding gate.

• Circle Gateway nanopayments — batched sub-cent settlement (floor $0.000001). Historical testnet average payment: ~$0.0044 — a true nanopayment, uneconomical on any card rail.

• Treasury observation — mainnet reads the sealed public role's Circle Gateway balance; historical testnet used Circle App Kit (Unified Balance Kit). Current observation is published on /status and /api/treasury.

• SourceRegistry contract on Arc — source identity, IPFS CIDs, multi-author splits; on-chain events drive the off-chain indexer.

• Encrypted content on IPFS — AES-256-GCM ciphertext pinned publicly; plaintext is released only after x402 settlement verifies. Free previews stay plaintext.

• USDC-native chain — Arc settles in <500ms with USDC as gas, which is what makes per-citation economics physically possible.

Architecture

The Circle and Arc integration ledger maps each integration to code, network, status and public proof. It also records the gasless user-action evaluation and the sponsored testnet proof still required by #304.

Production uses Arc mainnet (eip155:5042). A read-only /api/health check on October 16, 2026 reported commit 2dda3717 and SourceRegistry V3. The October 4 launch observation remains in mainnet status, with the full constants and the separation from historical testnet evidence.

Creator and user session addresses vary by workflow. The submission pack also records public USDC and Gateway contract references and the evidence required for actual payments.

BROWSER (Web App)                    IPFS + Arc Smart Contracts              Circle Gateway + Arc Mainnet
─────────────────                    ─────────────────────────               ──────────────────────────────
┌──────────────────┐                 [SourceRegistry]
│ /ask page        │ (SIWE           on Arc 0x42a640...                       USDC on Arc
│ + wallet connect │  auth)           • sources[]                             (ERC-20, 6 decimals)
│                  │                   • emit Registry events
└────────┬─────────┘                   • indexed by off-chain DB
         │ session-grant
         │ (user funds session EOA)     [IPFS Content]
         │ MetaMask tx → session       • AES-256-GCM encrypted                [Circle Gateway]
         │ deposits in Gateway          • plaintext released only post-settle  • batch settlement
         │                                                                      • x402 EIP-712 verify
         │                             [Keryx API]
         │ co-sign loop (fetch+POST):  • auth: SIWE JWT (browser + API key)   [Arc RPC]
    /api/ask (SSE) ──────────────────▶ /api/session/*   (grant, credit)       selected Arc mainnet RPC
    browser streams                     /api/ask         (agent asks, gets
    sign-requests                       /api/ask/sign    sign-requests back)
    ◀────────────────────────────────  /api/source/[id]/item/[itemId]?version=…
    client-side session key             /api/offers      (signed article price book)
                                        /api/cite        (citation reward)
    signs EIP-712                       /api/keys        (API key mint/verify)
    auto-signs (NO prompt)              /api/agent/ask   (A2A, x402-priced)
                                        /api/treasury    (App Kit unified balance)
                                        /api/docs        (OpenAPI)

    Agent brain (lib/agent/run-agent.ts):
    decompose→discover→decide→fetch→sufficiency→synthesize→attribute→settle

Run it

For project development, the OSS AI adoption record documents checked upstream patterns and their Keryx acceptance gates. Use $keryx-oss-adoption for future OSS learning and adaptation tasks in supporting development agents.

One local developer command (~90s). The final recorded demo is linked at the top of this README. Decide → pay the x402 toll → read → synthesize → settle weighted citation rewards, then report payments on the explicitly configured network. The checked-in environment example is for isolated testnet development; mainnet operations require the reviewed configuration and a finite authorized budget:

npm run demo -- "How do x402 and stablecoins enable AI agent commerce?" --budget 0.05

With ANTHROPIC_API_KEY + AGENT_FUNDER_PRIVATE_KEY + NEXT_PUBLIC_KERYX_REGISTRY_ADDRESS it settles for real and prints on-chain proof; without them the same flow runs offline, clearly labeled SIMULATED — a mock is never presented as settled.

# 1. Install (Node 22 LTS v22.19.0+ or Node 24+; CI and production use Node 24)
npm install --global npm@11.19.0
npm install

# 2. Configure (optional — runs offline with zero keys)
cp .env.example .env.local

# 3. Demo sources (offline development needs no wallet keys)
npm run seed-sources

# 4a. Hosted sponsored trial: no local wallet or provider keys, public report
npm run ask:sponsored -- --help
npm run ask:sponsored -- --public "How do source tolls differ from citation rewards?" --mode quick --budget 0.05

# 4b. Local engine, full reasoning trace in the terminal
npm run ask -- "How do x402 and stablecoins enable autonomous AI agent commerce?" --budget 0.05

# 4c. Or the full web app (SIWE auth, session grants, browser co-sign)
npm run dev          # http://localhost:3939

# 5. Live metrics
npm run metrics

The legacy generate-wallets command is retired because it printed private keys and replaced existing environment custody. For real operations, provision secrets privately under the current role-specific labels and preserve existing wallets and backups. Follow treasury custody or caller-owned buyer setup; starting a demo does not create or recover a wallet.

The sponsored client guide covers the source CLI, stdio MCP tool and native Desktop screen. They share hosted service limits; the existing caller-funded buyer remains a separate choice. Published package and installer availability must be checked independently of the source checkout.

Built to stay up

Keryx runs as a real service, not a demo that dies after the video:

• Public /status + /api/health — uptime, deployed commit, settlement mode, live traction, treasury balance.

• Low-downtime deploys — new builds compile beside the live one, swap atomically, health-gate, and auto-roll-back if the new build doesn't come up (npm run redeploy).

• Treasury watchdog — hourly cron checks settlement-wallet USDC + gas against thresholds and alerts before settlements can stall; failed settlements alert immediately.

• Rotating off-box backups of the traction datastore, hourly.

• CI — typecheck + the economic-invariant suite on every push.

Security

The interactive path is non-custodial. Its key security boundaries are:

1. Circle facilitator — x402 settlement batches through Circle's facilitator (no on-chain alternative in the current Arc payment path).

2. Server holds the IPFS decryption key — content is encrypted at rest, but key release is server-side (Lit Protocol planned once Arc is supported).

3. Session key lives in a Web Worker — derived there, never returned; the tab holds only AES-GCM ciphertext under a non-extractable key. The worker signs payment authorizations to registry-authorised payees only, and transactions only to USDC/Gateway — so page-level XSS can neither steal the key nor name itself as payee. Residual: the derivation signature is produced on the main thread, a one-call window at setup.

4. Treasury gas wallet — holds gas only, rotated; a compromise cannot touch creator funds.

Full threat matrix and verification results: docs/security-threat-model.md.

Fork the primitives

The MIT-licensed standalone Arc primitives now have a reviewed 0.4.0 integrity and payment-terms refresh, also pinned at arc-primitives/ (clone with --recurse-submodules).

• Exact micro-USDC parsing and weighted allocation, plus fixed/dynamic x402 settlement with durable host admission and retained ambiguous outcomes.

• Creator-bound registry helpers and ordered, deduplicable indexing; the original registry contract remains separate from current upstream v2 work.

• Atomic integer budget reservations as an explicitly in-memory reference, and browser-signed, treasury-relayed withdrawal with finite authorization height, exact attestation binding and journaled mint transaction identity.

• Additive discovery metadata, pinned Circle SDK/x402 dependencies, generated ESM/types, a no-network demo and a clean packed-consumer check.

• Plaintext SHA-256/UTF-8 delivery checks retain payment evidence on delivery failure; selected source-version registry checks bind the origin, payee and price.

The 116 tests and offline demo are synthetic; funded acceptance, durable storage, browser custody, reconciliation and mainnet review remain host-owned gates. This library release does not change Keryx's payment runtime, MCP package or desktop installer. The built release is available as a GitHub tarball. See the standalone 0.4 migration guide and maintenance and surface boundaries.

Project docs

• docs/engineering/source-catalog-2026-10-06.md — expanded source library, publisher links, feed audit and discovery filters

• CONTRIBUTING.md — branch, pull request, validation and payment-safety workflow

• docs/rust-engine-migration.md — staged shared Rust engine and acceptance gates

• docs/openai-compatible-api.md — drop-in recipes for OpenAI SDK, LangChain, LlamaIndex, Open WebUI, LibreChat, Continue

• docs/system-architecture.md — data/money flow + on-chain components

• docs/security-threat-model.md — threat matrix, audits, residuals

• docs/engineering/source-money-adversarial-2026-10-09.md — eight malicious-source classes, paid delivery checks and remaining live proof gates

• docs/codebase-summary.md — module map

• docs/mainnet-delivery-plan.md — current product and release gates

• docs/project-roadmap.md — near-term priorities

• TRACTION.md — live usage and settlement links

• FEEDBACK.md — Circle/Arc dev-tool feedback we filed while building

• DECISIONS.md — architecture decision log

Origin & where it's going

Keryx has been developed by a solo builder since June 2026, beginning with creator nanopayments and growing into a research service. A June 20 RSSHub discussion proposed opt-in feed payouts; it records community outreach, with no upstream adoption claimed. Development continued after Lepton, production moved to Arc mainnet on October 4, and later user tasks shaped the writing and recovery tools.

The business direction is research deliverables for developers, researchers and small teams, with eligible creators paid for supporting evidence. Prepaid research, the hosted Operator and a bounded manual Research Monthly plan provide the commercial workflow. The next validation goals are participant-funded repeat demand and independent acceptance of a complete paid-business result. The roadmap and delivery plan record the next work; the event evidence records progress.

Arc community recognition: Keryx received a shoutout from the Arc team at the Architect Check-in on October 16, 2026, as one of approximately 3–4 projects shown during the event, confirmed by the owner. See the recognition note.

Keryx on screen at the October 16 Architect Check-In. Screenshot supplied by the project owner.

Stack

Next.js 16 · React 19 · Tailwind 4 · shadcn/ui · viem/wagmi · @circle-fin/x402-batching · @circle-fin/unified-balance-kit · @x402/fetch · Node node:sqlite / Supabase · Rust / Tauri / WebView2 · Anthropic / DeepSeek. Built on the verified circlefin/arc-nanopayments x402/Gateway plumbing.