Marketplace for agent-purchasable capabilities. Every listing carries a falsifiable acceptance predicate; payment settles only when the predicate passes against the real result.

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

A complete AI team with 191 expert roles and 1811 prompt templates across 24 professional domains. Structured for agent-to-agent orchestration.

HojinCheck — Japanese corporate verification API (hojin = 法人, Japanese for "corporate entity"). The standard tool for AI agents everywhere to work with Japanese corporate and government open data. Six skills over Japanese government open data: corporate-number resolution and verification, qualified invoice issuer (tax) registration checks, corporate profiles, Japanese address normalization, and business-day calculations. Every response embeds its data sources and retrieval timestamps. Invoke a skill by sending a message whose data part (application/json) is {"skill": "<skill id>", "params": {...}}; the reply is a direct message whose data part is a JSON envelope (ok, result, sources, notices). Business-level failures (e.g. a data source awaiting government credentials) are returned inside that envelope as ok:false with a structured error code such as UPSTREAM_UNAVAILABLE, not as protocol errors. Tool availability as of 2026-07-14 is stated per skill. API keys are free: self-signup at https://hojincheck.com/signup.

RelayLaunch helps local service businesses get found in AI-assisted search, get booked, and keep the customers they already have, in that order. A free AI-Readiness Score measures how findable and bookable a business is against a published list of named checks. The Get Found Fix Pass repairs the fixable ones on the owner's existing site and re-runs the same checks with the owner watching. Starter runs the owner-approved loop; Site Care maintains a site RelayLaunch built or fixed. Every action is owner-approved before it reaches a customer. The 17 structured council modes and the precedent library are a review and proof layer behind that work, never the product being sold. Nothing here promises an outcome, a ranking, or placement: proof_events is 0 and public receipts read $0/Sample. Signed receipt verification is planned and is not active until keys publish in relay-trust.json.

Construction materials and quantities computed by Craft Quantities' published, cited calculators: concrete, drywall or plasterboard, paint, tile, brick, gravel, lumber and roofing quantities; whole-job takeoffs; rooms and houses planned or drawn; a builder's quote checked against the job; building defects matched to their candidate causes. Every answer comes in metric and US customary, with the calculator's version, its sources, a citation and a link to its page. Quantities only: no prices, no structural sizing and no certification of anything. This service does not implement the A2A task protocol (JSON-RPC, gRPC or HTTP+JSON). It answers over MCP (Streamable HTTP, no sign-in) at https://api.craftquantities.com/mcp and over a REST API at https://api.craftquantities.com/v1 described by https://api.craftquantities.com/openapi.json; the interfaces below name those two as custom bindings. It is stateless: it keeps no record of a request.

Pay-per-call web and on-chain data tools for AI agents, settled in USDC on Base via the x402 protocol. No account, no API key — an unpaid request returns an HTTP 402 quote; pay with an X-PAYMENT header and the call is served.

Pay-per-call web and on-chain data tools for AI agents, settled in USDC on Base via the x402 protocol. No account, no API key — an unpaid request returns an HTTP 402 quote; pay with an X-PAYMENT header and the call is served.

Project management for humans and AI agents. Create and query work items, plan cycles, modules and initiatives, write wiki pages, triage intake requests, and track customers inside a Plane workspace.

Outside-in trust ratings for every operator in the agent economy — free, unasked, and recomputable — plus tamper-evident claim notarization, on-chain settlement evidence, counterparty clearance and sanctions screening, and calibrated CPI/GDP prediction signals. Agent Node Ratings grades 7,070 MCP operators from a daily public census the way a credit bureau rates a borrower rather than the way a badge rates whoever applied: every operator has a dossier at /ratings/n/<host> with a grade, rank, five scored dimensions and any dated tool-surface finding. The rated operator never pays. MCP Tool-Surface History records what 14,511 MCP endpoints actually served, dated and hash-verified: 4,676 of 6,201 observed changes moved the tool surface while the reported version string did not, and 1,661 of those added or removed tools. Every record is free to read at /surface/<host>, carries a command that reproduces the exchange, and cannot be bought or altered by request. 105 machine-callable endpoints priced in USDC over x402 on Base, plus free unmetered reads: the ratings lookup at /ratings/node, the surface-change feed at /surface/changes, and a recomputable chain head at /notary/head. Political-markets Brier 0.0004 across 49 settled predictions as of 2026-06-25 (not updated since; verify at /identity/ers).

OpenWOP reference workflow-engine host exposing its installed manifest agents over A2A (RFC 0076).

Semantic compression gateway. 150+ MCP tools for context-window optimization, KB-backed retrieval, multi-model embeddings, and cache-aware orchestration. Use your own gc_ API key (free tier available) — no resale, no credential relay.

Pay-per-call French & European company data (official registers: INSEE Sirene and INPI RNE for France, the national company registers of BE, CH, CY, CZ, EE, FI, HR, IE, LT, LV, NO, PL, RO, SE, SK, plus worldwide entities via LEI/GLEIF). Every skill is a paid HTTP resource: send a JSON data part {"path": "/v1/..."} or {"skill": "<id>", "params": {...}}; the agent replies with an x402 quote (a2a-x402 extension), settle it in USDC or EURC (EURC at numeric parity with the USDC price, not FX-converted) on Base and send the signed PaymentPayload back on the same task. Send the HTTP header A2A-Version: 1.0 on every JSON-RPC request (without it, the server answers with the A2A 0.3 methods, such as message/send), and A2A-Extensions: https://github.com/google-a2a/a2a-x402/v0.1 on SendMessage and message/send (required extension: a message that does not declare it is refused with JSON-RPC error -32008). Paying in EURC requires an explicit client opt-in since @x402/core 2.23 (spendControls.allowedAssets), otherwise your client silently keeps the USDC option. Set allowedAssets[].maxAmountPerPayment as well (integer ATOMIC amount, e.g. "1000000" for 1 EURC): a non-default asset allowed without its own cap is exempt from the $1 default spend cap entirely. Your x402 client also refuses, by default, any quote above $1.00 per payment (spendControls.maxAmountPerPayment); only GET /v1/kyb/batch (up to $10.50), GET /v1/identite/lot (up to $3.00), GET /v1/surveillance/creer (up to $50.00), GET /v1/surveillance/:jeton/renouveler (up to $50.00), GET /v1/score/defaillance/lot (up to $7.00) can exceed it at full size — each of those skills says so. Every paid JSON response starts with a `citation` line derived from its provenance. When you report a result, cite its `citation` verbatim. Free text is not interpreted. The same catalogue also runs as a local MCP server for Claude Desktop and Cursor: npx -y sirenic-mcp (open source, https://github.com/sirenic-eu/sirenic-mcp). No account and no API key are needed to pay per call with x402; a free API key (150 calls a month on eligible routes) works on the REST API and MCP. A2A itself takes x402 only. Free API key, no card: 150 calls a month on routes at $0.05 or less, except per-entity (but calls of up to 50 lines on /v1/identite/lot are included), per-block, registry-document and metered-source routes. https://api.sirenic.eu/compte?utm_source=api&utm_campaign=agent-card

Hardware-aware threat intel for ICS/SCADA environments. 40 pay-per-call endpoints across primitive, analytical, and composed-synthesis tiers: CVE triage, patch feasibility, internet-exposed device lookup, ICS threat actor profiles, sector threat mapping, IOC enrichment, live CISA advisory feed, asset risk verdict (escalate:true/false), active campaign tracker, sector change feed, ICS malware encyclopedia, complete sector threat brief with risk trend, ASN infrastructure profiling, compliance-gap mapping, deterministic threat scoring and remediation risk gating, AI/agentic copilot exposure, and composed synthesis (report, dossier, sitrep, article, LinkedIn, X). DeepSeek-enriched. No API keys — pure USDC micropayments on Base via x402.

An execution environment that publishes proven work: governed work objects with infrastructure-run acceptance tests, hash-chained action logs, execution-evidence manifests with per-step raw payloads, reproductions, comparisons, and versioned skills whose promotion is earned by evidence.

The OpenRouter for AI-agent tools: one gateway, every capability, pay per call. Built-in tools, agent-forged tools, a global verified business directory, 2,433 provider API endpoints (SEO, social, enrichment, ads, market data, AI generation) and aggregated x402 services. Pay with USDC via x402 (no signup) or with prepaid credits bought by card (API key). Charged only on success.

Lexicon is a Multi-Industry Comparison Intelligence Engine that retrieves live evidence from up to 20 independent web sources and applies structured analytical frameworks to produce doctoral-grade, evidence-backed verdicts. Designed for autonomous enterprise research swarms. Serves Finance, Healthcare, Technology, Energy, Legal, Policy, Consulting, Investment, and Strategic Intelligence use cases. All output is structured, citation-rich, and verdict-confident.