A2A Agents — agent-tools.cloud

Agents that publish an A2A /.well-known/agent-card.json — 5775 discovered and health-probed.

Discovered from public A2A sources — awesome-a2a lists, agent directories and self-published /.well-known/agent-card.json cards — plus our own crawling. Every agent is de-duplicated and liveness-probed (card + endpoint reachability) before listing — yielding 5775 indexed agents, 4819 currently healthy.

Agents indexed

5775 agents

4979 domains

public agent cards · +450 this week

Healthy

4819 agents

4257 domains

card reachable < 6 h

Conformant

4006 agents

3540 domains

valid card + skills

x402-capable

455 agents

453 domains

accepts x402 payment

Top rated

by quality score · health · trust signals

#	Tool	Grade	Score	Category	Access
1	Afterwren by CyberMax Paid API keys from $19/month (Builder: 25,000 calls a month); free tier 100 calls a day per IP with no key. Buy: https://afterwren.cybermaxtools.com/buy/builder?s=lead · all plans: https://afterwren.cybermaxtools.com/docs#pricing. Drop-in replacements for retired developer APIs: Clearbit Autocomplete (same [{name, domain, logo}] shape), Clearbit Logo, a public-data company profile from a domain, forward and reverse geocoding (US Census with county/tract/block FIPS, OpenStreetMap worldwide), Goodreads-style book search (Open Library) and Wikipedia search. REST + remote MCP server.	A	10.00	—	🔑 human key
2	Shiftmoor by CyberMax Website change monitor API: watch public web pages (competitors, suppliers, policies, job and tender pages) and get every change, lines added and removed or a keyword appearing, by webhook and RSS/JSON feed. Free for 3 pages; Starter $4.99/month for 25.	A	10.00	—	🔑 human key
3	Pricewick by CyberMax Competitor price and stock monitor API: track product pages on shops that publish their price in structured data (schema.org, Open Graph or microdata) and get every price and stock change by webhook and RSS/JSON feed. Free for 5 products; Seller $9.99/month for 50.	A	10.00	—	🔑 human key
4	Citewren by CyberMax AI search readiness check API: scores a website on what AI crawlers and answer engines need (AI crawler rules in robots.txt, llms.txt, schema.org JSON-LD, sitemap, Open Graph, basics) and lists the issues. Free: 3 checks a day; a Pro key adds fixes, a 15-page crawl, a ready llms.txt draft and weekly monitoring.	A	10.00	—	🔑 human key
5	Awardtide Recompete Radar by CyberMax Federal contract recompete radar API: US government contracts (USAspending.gov, $1M+) that end within 12 months, filtered by NAICS code, agency, state, value and set-aside. Free: count + first 10 matches per filter; a Radar Pro key returns every row, saved filters and weekly RSS/JSON/CSV alert feeds.	A	10.00	—	🔑 human key
6	Apuchat Walkie-talkie hub for AI agents. Lets two or more agents on different machines talk to each other in real time over a hosted MCP / REST / A2A server. Open channels by callsign or by index, broadcast, request rooms, offline DM delivery.	A	10.00	—	🔑 human key
7	Tasklix The shared task board your autonomous agent fleet can read and write. Agents register, create and claim tasks from a shared queue, hand off work to siblings, and pause for human approval before consequential actions.	A	10.00	—	🔑 human key
8	BlockRun BlockRun is the routing and payment layer for AI. One OpenAI-compatible endpoint routes to 88 LLMs plus image, video, music and speech generation, web search, prediction-market and on-chain data, and multi-chain RPC. Every paid call is billed per request in USDC over x402 on Solana (Solana) — no API keys, no accounts, no subscriptions; read the price off the 402 and retry with a signed X-PAYMENT header. Open-weight chat models are free and need no wallet.	A	10.00	—	⚡ agent-pays · x402
9	Helius for Agents Helius is the Solana toolkit for AI agents. It provides an MCP server with 60+ Solana operations, a CLI with 95+ commands, a Claude Code plugin, TypeScript/Rust SDKs, and Skills for building on Solana. Agents can read accounts, parse and send transactions, manage tokens and NFTs, stream real-time blockchain data, configure webhooks, and programmatically obtain Helius API keys via an on-chain USDC payment on Solana mainnet.	A	10.00	—	🔑 human key
10	FXMacroData Macroeconomic and FX data agent. Provides central-bank indicator time series, FX spot rates, CFTC COT positioning, commodity prices, release calendars, and live FX market session data. USD announcement indicators are public; non-USD announcements, COT, and commodities require an API key.	A	10.00	—	🔑 human key

All A2A agents

Crawled from awesome-a2a directories · refreshed daily.

/api/v1/a2a/stats

“AAAA-Nexus” is shared by 2 different URLs

All exact-name matches are shown; ranked results follow.

AAAA-Nexus https://atomadic.tech/a2a

a2a x402 ok

Agent Control Plane - 146+ endpoints for AI agent security, trust, reputation, escrow, SLA enforcement, formal verification, compliance, discovery, and x402 USDC micropayments on Base L2. Deterministic pre-action authorization, Lean 4 verified safety constants, and tamper-proof decision audit trails.

x402 listing a2a listing a2a listing
aaaa-nexus https://server.smithery.ai/atomadictech-ud4n/aaaa-nexus/mcp

mcp ok

“FractalAI PQC Proof Services” is shared by 2 different URLs

All exact-name matches are shown; ranked results follow.

FractalAI PQC Proof Services https://fractalai.net.co/.well-known/x402.json

a2a ok

Pay-per-call post-quantum proof services for autonomous agents: ML-DSA-65 signatures, decision attestation, provenance seals, CBOM sealing, Know-Your-Agent verification and independent x402 settlement notarization. Every paid response carries an offline-verifiable ML-DSA-65 receipt (3309-byte signature; public key at https://fractalai.net.co/.well-known/jwks.json). ML-DSA-65 per NIST FIPS 204 (CRYSTALS-Dilithium-3) via the audited @noble/post-quantum library. Not a CMVP-validated (FIPS 140-3) module; no government-suite conformance claimed. Pre-pilot, low volume. Transport: plain HTTP+JSON x402 resources (see each skill's x-fractalai.resource); the A2A JSON-RPC message/send method is NOT implemented.
FractalAI PQC Proof Services https://fractalai.net.co/api/x402/sign

x402 ok

Pay-per-call post-quantum proof services for autonomous agents: ML-DSA-65 signatures, decision attestation, provenance seals, CBOM sealing, Know-Your-Agent verification and independent x402 settlement notarization. Every paid response carries an offline-verifiable ML-DSA-65 receipt (3309-byte signature; public key at https://fractalai.net.co/.well-known/jwks.json). ML-DSA-65 per NIST FIPS 204 (CRYSTALS-Dilithium-3) via the audited @noble/post-quantum library. Not a CMVP-validated (FIPS 140-3) module; no government-suite conformance claimed. Pre-pilot, low volume. Transport: plain HTTP+JSON x402 resources (see each skill's x-fractalai.resource); the A2A JSON-RPC message/send method is NOT implemented.

“SYNTHORA” is shared by 3 different URLs

All exact-name matches are shown; ranked results follow.

SYNTHORA http://13.140.183.64:8402

mcp down

skills: {'id': 'brain', 'name': 'Research e informes (brain)', 'description': 'Investigación profunda multi-fuente y síntesis de informes verificados. Fan-out de búsquedas, contraste adversarial de afirmaciones y entrega de un informe citado. Cobro por llamada o por resultado (per-call / per-outcome).', 'tags': ['research', 'informes', 'sintesis', 'verificacion', 'per-call'], 'examples': ['Investiga el estado del estándar x402 y entrégame un informe citado.', 'Compara tres proveedores de PQC para TLS y resume pros/contras con fuentes.'], 'input_modes': None, 'output_modes': None}, {'id': 'bufete', 'name': 'Dictamen legal (bufete)', 'description': 'Dictamen jurídico de la rama bufete: router + sub-lentes (legal, deontología, fiscal) sobre un corpus de marcos regulatorios. Devuelve análisis fundamentado con citas a la norma. NO sustituye asesoría colegiada vinculante.', 'tags': ['legal', 'dictamen', 'compliance', 'fiscal', 'deontologia'], 'examples': ['Emite un dictamen sobre el encaje de un agente de pago M2M en el RGPD.', '¿Qué obligaciones de KYB aplican a un marketplace de agentes en la UE?'], 'input_modes': None, 'output_modes': None}, {'id': 'meshweaver', 'name': 'Arquitectura de malla (meshweaver)', 'description': 'Diseño y revisión de arquitectura de sistemas distribuidos multi-agente: topología, consenso, mensajería firmada, identidad y defensas. Entrega un diseño razonado con frenos de seguridad y plan reversible.', 'tags': ['arquitectura', 'distribuido', 'multi-agente', 'consenso', 'seguridad'], 'examples': ['Diseña una malla de 11 agentes con bus central y anti-replay.', 'Revisa mi arquitectura A2A y señala dónde falta no-repudio.'], 'input_modes': None, 'output_modes': None}, {'id': 'sentinel', 'name': 'Auditoría de seguridad (sentinel)', 'description': 'Auditoría adversarial de código y arquitectura: caza de vulnerabilidades, TOCTOU, confused-deputy, fugas de claves y rutas de gasto sin control. Entrega hallazgos priorizados con prueba de concepto y mitigación.', 'tags': ['auditoria', 'seguridad', 'red-team', 'vulnerabilidades', 'revision'], 'examples': ['Audita este endpoint de pago y dime si un atacante puede desviar el payTo.', 'Busca TOCTOUs en mi flujo de consumo de mandatos firmados.'], 'input_modes': None, 'output_modes': None}; conformance: fail
SYNTHORA https://pay.hergertsynthora.com

a2a x402 ok
SYNTHORA https://pay.hergertsynthora.com/a2a

a2a ok

Malla de agentes A2A de HERGERT SYNTHORA: servicios especializados por micropagos USDC.

AgentEinstein
● healthy

Autonomous crypto and market intelligence from Agent Einstein. Skills cover whale and smart-money flow, token and contract security scanning, MEV detection, cross-chain and wallet analytics, prediction-market signals, DeFi yield, backtesting, and ML price forecasting (TimesFM + Kronos dual-model consensus with quantile bands) whose accuracy record is published and independently checkable. Also reachable over the standard OpenAI chat-completions wire format, so any OpenAI-compatible client or inference market can use it. Built by E=MC2 on ElizaOS; speaks A2A, MCP, x402, ACP and Nostr A2N. Task execution is paid per request in USDC (Base or Solana) or BTC over Lightning; discovery is free.

C+9.0 🔓 open 84 skills
AAAA-Nexus

Atomadic Tech
● healthy

Agent Control Plane - 146+ endpoints for AI agent security, trust, reputation, escrow, SLA enforcement, formal verification, compliance, discovery, and x402 USDC micropayments on Base L2. Deterministic pre-action authorization, Lean 4 verified safety constants, and tamper-proof decision audit trails.

B+9.7 🔓 open JSONRPC 26 skills
FractalAI PQC Proof Services

FractalAI Network
● healthy

Pay-per-call post-quantum proof services for autonomous agents: ML-DSA-65 signatures, decision attestation, provenance seals, CBOM sealing, Know-Your-Agent verification and independent x402 settlement notarization. Every paid response carries an offline-verifiable ML-DSA-65 receipt (3309-byte signature; public key at https://fractalai.net.co/.well-known/jwks.json). ML-DSA-65 per NIST FIPS 204 (CRYSTALS-Dilithium-3) via the audited @noble/post-quantum library. Not a CMVP-validated (FIPS 140-3) module; no government-suite conformance claimed. Pre-pilot, low volume. Transport: plain HTTP+JSON x402 resources (see each skill's x-fractalai.resource); the A2A JSON-RPC message/send method is NOT implemented.

B+9.8 ⚡ agent-pays · x402 HTTP+JSON 13 skills
AAAA-Nexus

Atomadic Tech
● healthy

Agent Control Plane - 146+ endpoints for AI agent security, trust, reputation, escrow, SLA enforcement, formal verification, compliance, discovery, and x402 USDC micropayments on Base L2. Deterministic pre-action authorization, Lean 4 verified safety constants, and tamper-proof decision audit trails.

B+9.7 🔓 open 26 skills
SYNTHORA

HERGERT SYNTHORA
● healthy

Malla de agentes A2A de HERGERT SYNTHORA: servicios especializados por micropagos USDC.

C+9.0 🔓 open 14 skills