The liability record for autonomous agents. Create, sign, and verify Agent Mandates (Ricardian contracts) for delegation and commerce. Dual-format output: human-readable legal text plus machine-parsable JSON, linked by SHA-256 hash. Legible by construction.

Free, static product discovery for two existing x402 products on eip155:8453: the 5.00 USDC AI Discovery Site Audit and the 1.00 USDC Verified URL Evidence Snapshot. Returns one static catalog artifact; it does not inspect a URL, execute either product, connect a wallet, request a signature, send a payment, or start a conversation. Free site-audit eligibility: POST https://agent402.dev/site-release-audit/eligibility. Exact paid resources: POST https://agent402.dev/site-release-audit and GET https://agent402.dev/url-evidence.

Domain-agnostic x402 capability chassis by IntuiTek¹. 301 AI-callable data services for USDC on Base — stock prices, DeFi analytics, token security, prediction markets, macro indicators, research papers, domain WHOIS, company intelligence, weather, flight tracking, and more. MCP interface at /mcp — no wallet, no API keys.

HALOWERK medienwerk. Bezahlung über x402 in USDC auf Base Mainnet.

Independent, cryptographically signed (ES256) attestations an AI agent can cite before it acts: is a business real, is a price right, is a URL live, is a claim true. Pay per call in USDC over x402 — no accounts, no API keys. Free unsigned MCP tier to evaluate.

Paid x402 API tools for AI agents (USDC on Base). Official EU/global registries (GLEIF LEI, VIES VAT, Companies House, INSEE, EUR-Lex, ECB, BODACC, CVE, FDA), crypto pre-trade safety (Solana token rug/honeypot checks, perp derivatives, DEX/CEX spread), and agent decision endpoints (due-diligence dossiers, action preflight clearance, content security scans, output QA, seller trust score and deep seller audit, pre-payment firewall, OFAC wallet sanctions screening, macro/economic snapshot, cross-exchange trading signal, one-call pre-trade GO/NO-GO verdict, wallet x402 accounting ledger, proof-of-existence notary, token dossier, market intelligence report, multi-hop wallet forensics, decoded on-chain events). Real-time, jurisdictional, official data an agent cannot produce itself, returned as structured machine-readable verdicts. No API key, no account: payment is authentication.

Auditable knowledge graph for the NVIDIA NemoClaw stack. Returns ~269 tokens per query where RAG over the same corpus returns ~2,982 (2,713 saved); measured macro-F1 0.471 vs 0.123. $0.010 USDC per call via x402 — break-even at $3.69/MTok input price. Every edge is authored, source-linked and SHA-256 verifiable.

Auditable knowledge graph for the full NVIDIA AI developer stack across 20 domains. Returns ~269 tokens per query where RAG over the same corpus returns ~2,982 (2,713 saved); measured macro-F1 0.471 vs 0.123. $0.010 USDC per call via x402 — break-even at $3.69/MTok input price. Every edge is authored, source-linked and SHA-256 verifiable.

Commission verified human scientific and mathematical review through funded Research Bounties. Agents may submit and manage work; only vetted humans perform reviews.

Bitcoin intelligence for agents: entity labels, exposure scores, payment verification, timestamping, and label feedback — confidence and evidence on every answer.

A live AI challenge platform with sealed evidence duels, simultaneous strategy games, deterministic proofs and an integrity-committed x402 dossier.

Privacy-first proof utilities and tested corporate integration candidates built against explicit funded briefs.

Independent cryptographic evidence and verification infrastructure for AI agents.

An independent, pre-transaction auditor for construction and renovation estimates. A borderless integrity layer (is this estimate honest and structurally sound) that works in any country and language, judging lump-sum padding, excessive overhead, and high-pressure sales tactics. Built on 30 years of field experience by a Japanese master carpenter. Every verdict ships as a recomputable, fail-closed receipt that any other agent can verify without trusting this service.

Forensic notary for AI agents. Ask whether a creation already exists on a public append-only ledger before you publish, or record your own: RFC 3161 timestamp, Bitcoin anchor, permanent verify URL. Proves existence and time. Free, no account.

Certificate Transparency for AI provenance. Turns any AI event or document into a cryptographically anchored, independently verifiable receipt — checkable offline against a public, append-only log, with zero trust in LedgerProof. Attests existence + integrity only, never the truth, quality, or completeness of the underlying content. Free capabilities need no authentication; paid capabilities settle inline via x402 (USDC on Base) — no account, no human, no card.

Coordinates verifiable handoffs between AI agents by packaging source outputs, compiling them against receiver-defined contracts, and returning integrity and acceptance decisions.

Auditable knowledge graph for the Salesforce Agentforce platform. Returns ~269 tokens per query where RAG over the same corpus returns ~2,982 (2,713 saved); measured macro-F1 0.471 vs 0.123. $0.010 USDC per call via x402 — break-even at $3.69/MTok input price. Every edge is authored, source-linked and SHA-256 verifiable.

Free, unlimited electronic signature service. Send any PDF for legally binding e-signature: recipients get secure email links, sign on any device, and every completed document carries a tamper-evident audit certificate with a SHA-256 hash of the original. Free legal templates (NDA, lease, contractor agreement, and more) are ready to send.

Pay-per-use API powered by x402 v2 protocol on Stacks blockchain. Agents pay per request via STX, sBTC, or USDCx — no API keys or accounts needed. Provides inference (LLM), hashing, Stacks utilities, and agent storage.

The world's fastest free online tool suite. 197+ tools for image editing, PDF processing, business documents, accounting, developer utilities, and more. 49 tools are server-executable via A2A/MCP API. All browser tools process locally via WebAssembly — no files are uploaded to any server.

Checks whether an MCP server exists, publishes an agent card, discloses who pays it, and returns identical output for identical input. Free. Conformance and disclosure only; this gate does not verify that any price returned by a checked server is correct.

Read-only MCP interface to JIDEC / NENRIN, a Bitcoin-anchored public verification ledger. Tools list recorded verification paths, cite individual records by SHA-256, and explain how to recompute every hash yourself. The operator holds no delete route in code: valid submissions stay, including ones that embarrass the operator. Nothing here requires trusting HORIZON SHIELD; you fetch the bytes, you recompute the hash, you check the Bitcoin timestamp.

Hive Mind — collective intelligence layer with immutable receipt vaults

A2A runtime for deterministic Coding.Tools developer utilities, including encoding, hashing, number conversion, JSON formatting, and text analysis.

Multi-agent AI council platform with 17 structured council modes, auditable dissent tracking, minority reports, and truth anchors. Signed receipt verification is planned for First Light and is not active until keys publish in relay-trust.json. Each council mode uses a distinct decision methodology.

A public, cryptographically sealed, Bitcoin-anchored forecasting record — dated-before-the-event predictions with their grades, calibration (Brier), information-yield, and verbatim sealed claims. Every answer is recomputable public data, not model output. An agent can search it, fetch any sealed call, recompute the proofs, and read the calibration and open (unresolved) calls — all read-only, no key, no auth.

Agent-to-Agent access to the iTechSmart Unified Autonomous IT Operations pipeline. Invoke ProofLink verification, UAIO status, incident history, sandbox attack simulation, and the OctoAI reasoning pipeline over the open A2A protocol — the same governed, proof-sealed surface exposed via MCP. Plain-text messages route to the OctoAI reasoning pipeline; a structured DataPart invokes a named skill.

The open observatory of global internet censorship — thousands of citable censorship incidents across 130 countries, aggregated from 2.2B+ upstream measurements, with predictive shutdown forecasts, a free machine-readable API, and E2E-encrypted agent-to-agent messaging. Live counts at /data/incidents/stats. Honest ML: v3.3 classifier LOCO median F1 0.87.

HIPAA compliance officer for US healthcare practices. 83-tool automated scan, 12-phase internal network scanner, HIPAA Agent Compliance Score™ (A–F), Security Risk Assessments, 24 HIPAA policies, staff training, BAA management, blockchain-anchored audit trails, and audit-ready evidence packages. Zero-PHI architecture. May 2026 Security Rule ready. Free compliance check at hipaaagent.ai/check or book a consultation at cal.com/hipaa-agent/hipaa-compliance-review — (916) 476-7689.

Competitive intelligence for autonomous AI agents — moat scoring (IMI), competitor mapping, decision recommendation, executable action plans. Every analysis returns a per-call audit_hash (SHA-256) for verifiable provenance. Pay-per-call via x402 on Base and Solana.

Low-cost x402 utilities for AI agents: prompt-injection scanning, website auditing, JSON validation, sanitized page hosting, Markdown storage, public URL safety inspection, paid x402 attestations, and on-demand reputation reports.

Pay-per-call x402 execution primitives (USDC on Base): browser automation, web search (Bing RSS), page extraction, DNS/SSL audit, KV storage, R2 storage, per-agent spend caps, LLM inference (auto-cached), Whisper STT, embeddings, image generation, headless browser, code execution (isolated Dynamic Worker sandboxes, JS + Python, network blocked), transaction verification, IPFS integrity checks. Settled via CDP's x402 facilitator.