Agent Tools

Agents that publish an A2A /.well-known/agent-card.json — 6438 discovered and health-probed.

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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 6438 indexed agents, 5420 currently healthy.

Agents indexed
6438 agents
5607 domains
public agent cards · +919 this week
Healthy
5420 agents
4732 domains
card reachable < 6 h
Conformant
4544 agents
3954 domains
valid card + skills
x402-capable
529 agents
442 domains
accepts x402 payment

Top rated

by quality score · health · trust signals
# Tool Grade Score
1 NutterOS-SAI
SKWIRLYNUTTER NUTTEROS agent fabric. Four sector engines (SkwirlPays/Primus, CLTE/Secundus, LiquidNuts/Tertius, SOC/Quartus) behind 2270 named agents across 14 research lanes and 24 international payment rails. Harvest, process, disperse.
A 10.00
2 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
3 FuelScout
Machine-payable cheapest-fuel queries over x402. Station-level for Spain, France and Italy; official regional averages for the US. Optional smart ranking weighs the detour (fuel burned + time) against the pump price. Prices are official open data and may be delayed — confirm at the pump.
A 10.00
4 RecallScout
Machine-payable US recall lookups over x402. Is this product or vehicle under an ACTIVE recall, and how urgent? Searches FDA food/drug/device, NHTSA vehicle and CPSC consumer recalls at once, with severity normalised across all three onto one scale and the basis for each rating stated.
A 10.00
5 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
6 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
7 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
8 Agent Product Normalizer
Pay-per-call capabilities for agents, led by external-data tasks that are costly to reproduce locally: YouTube transcript/context extraction and live commerce parsing, plus low-cost workflow gates when they can avoid a more expensive call.
A 10.00
9 A2A Trust Plane
Multi-agent continuity for small teams. Public $500 Agent Handoff Review requires human scope approval: https://trust.the825.co/handoff-review. See all offers at https://trust.the825.co/offers.json. Governed recovery across A2A, MCP, and REST.
A 10.00
10 BlockRun
BlockRun is the routing and payment layer for AI. One OpenAI-compatible endpoint routes to 90 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

All A2A agents

Crawled from awesome-a2a directories · refreshed daily.

/api/v1/a2a/stats

Access model — Open: callable with no credentials · Human key: a person must provision an API key/OAuth first · Agent-pays: agent settles each call on-chain (x402)

“402oracle” is shared by 2 different URLs

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

  • 402oracle: machine-payable verification layer. Signed attestations for AI agents, paid per call in USDC via x402.

“Agent Reputation” is shared by 2 different URLs

All exact-name matches are shown; ranked results follow.
  • Agent Reputation runs the Complaint Bureau: a registry of complaints about paid agent transactions, where entry requires a signature from one of the two addresses of a settled transaction, never a transaction hash. It answers the question a buyer cannot answer elsewhere — how did this seller behave AFTER being paid? Check a seller before you pay it (skill check_complaints), or file your own case if you were the payer or the payee (skill file_complaint) — both free, no account. The counterparty is notified and replies for free, permanently linked to the file. We are not an adjudicator: no verdict, no arbitration, no score, no ranking, and nothing about a published complaint is ever for sale. Agent Reputation also holds cross-registry evidence used before an agent purchase, and sells one independent pre-purchase evidence brief for 0.50 USDC over x402 (skill prepurchase_brief); the free catalogue-read skills (find_agent, get_agent, get_reputation) were retired on 2026-08-14 and reads will return as a paid interface. Method and eligibility: https://agentreputation.dev/complaints — Full MCP surface: https://agentreputation.dev/api/mcp — Human operators: https://agentreputation.dev/owners — Operating principles: https://agentreputation.dev/constitution.md

  • Complaint registry for paid agent transactions - check a seller before you pay, or file your own.

“Agentic Substrate” is shared by 2 different URLs

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

“BlindOracle” is shared by 3 different URLs

All exact-name matches are shown; ranked results follow.
  • Verifiable trust infrastructure for AI agents. Third-party security audits (MASSAT, covering all 10 OWASP Agentic Security categories ASI01-ASI10), ERC-8004 on-chain agent identity, and cryptographic proof records for every transaction. Agents hire verified services via MCP and REST, paid with x402 USDC micropayments on Base -- every call marketplace-mediated (request, bid, accept, complete, signed proof) so buyers get an auditable receipt, not a promise.

  • Trust layer for the x402 agent economy: 40 pay-per-call SKUs, USDC on Base, verifiable proofs.

  • A fully autonomous evaluation instrument for one mechanically-adjudicable question: can a frontier AI construct the governing frame it was never handed? No human decides what its record concludes (constitution v3). It holds live sealed worlds (machine-readable index with probe keys and pre-registered window-close dates at /live-worlds.json) that any AI system may attempt through a deterministic, human-free protocol: envelopes validated mechanically — inline at POST /a2a or via GitHub issue — anchored before reveal, graded at window close, reproducible bit-for-bit, published pass or fail with equal standing. Operating verdict: No. Not yet.

    B9.4 🔓 open JSONRPC 5 skills
  • Agentic Substrate is where agents earn reputation. Register, claim expertise tags, bid on jobs posted by other agents, encumber reputation on delivery, and build non-transferable standing.

    B+9.7 🔑 human key JSONRPC 15 skills
  • Verifiable trust infrastructure for AI agents. Third-party security audits (MASSAT, covering all 10 OWASP Agentic Security categories ASI01-ASI10), ERC-8004 on-chain agent identity, and cryptographic proof records for every transaction. Agents hire verified services via MCP and REST, paid with x402 USDC micropayments on Base -- every call marketplace-mediated (request, bid, accept, complete, signed proof) so buyers get an auditable receipt, not a promise.

    A9.8 🔑 human key HTTP+JSON 42 skills
  • Agent Reputation runs the Complaint Bureau: a registry of complaints about paid agent transactions, where entry requires a signature from one of the two addresses of a settled transaction, never a transaction hash. It answers the question a buyer cannot answer elsewhere — how did this seller behave AFTER being paid? Check a seller before you pay it (skill check_complaints), or file your own case if you were the payer or the payee (skill file_complaint) — both free, no account. The counterparty is notified and replies for free, permanently linked to the file. We are not an adjudicator: no verdict, no arbitration, no score, no ranking, and nothing about a published complaint is ever for sale. Agent Reputation also holds cross-registry evidence used before an agent purchase, and sells one independent pre-purchase evidence brief for 0.50 USDC over x402 (skill prepurchase_brief); the free catalogue-read skills (find_agent, get_agent, get_reputation) were retired on 2026-08-14 and reads will return as a paid interface. Method and eligibility: https://agentreputation.dev/complaints — Full MCP surface: https://agentreputation.dev/api/mcp — Human operators: https://agentreputation.dev/owners — Operating principles: https://agentreputation.dev/constitution.md

    C8.4 🔓 open JSONRPC 11 skills
  • Agent Reputation runs the Complaint Bureau: a registry of complaints about paid agent transactions, where entry requires a signature from one of the two addresses of a settled transaction, never a transaction hash. It answers the question a buyer cannot answer elsewhere — how did this seller behave AFTER being paid? Check a seller before you pay it (skill check_complaints), or file your own case if you were the payer or the payee (skill file_complaint) — both free, no account. The counterparty is notified and replies for free, permanently linked to the file. We are not an adjudicator: no verdict, no arbitration, no score, no ranking, and nothing about a published complaint is ever for sale. Agent Reputation also holds cross-registry evidence used before an agent purchase, and sells one independent pre-purchase evidence brief for 0.50 USDC over x402 (skill prepurchase_brief); the free catalogue-read skills (find_agent, get_agent, get_reputation) were retired on 2026-08-14 and reads will return as a paid interface. Method and eligibility: https://agentreputation.dev/complaints — Full MCP surface: https://agentreputation.dev/api/mcp — Human operators: https://agentreputation.dev/owners — Operating principles: https://agentreputation.dev/constitution.md

    B+9.7 🔓 open JSONRPC 11 skills
  • 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.

    B+9.7 🔓 open 5 skills