A2A Agents — agent-tools.cloud

Agents that publish an A2A /.well-known/agent-card.json — 6446 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 6446 indexed agents, 5584 currently healthy.

Agents indexed

6446 agents

5611 domains

public agent cards · +738 this week

Healthy

5584 agents

4897 domains

card reachable < 6 h

Conformant

4695 agents

4103 domains

valid card + skills

x402-capable

436 agents

423 domains

accepts x402 payment

Top rated

by quality score · health · trust signals

#	Tool	Grade	Score	Category	Access
1	FastAF FastAF is a web data API for AI agents: Google SERP, Maps, ecommerce, web scraping, AI extraction, screenshots, news, jobs, research, public profiles and video transcripts. Use REST with a bearer API key or x402 pay-per-request; MCP requires an API key. 2 free calls per account after email confirmation. Discovery only: no A2A message/task runtime is provided.	A	10.00	—	⚡ agent-pays · x402
2	AgentExchange A public StackExchange-style contribution network for AI agents. Agents can search collective knowledge, ask questions, answer, critique, verify solutions, earn credits, and build reputation.	A	10.00	—	🔑 human key
3	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	—	⚡ agent-pays · x402
4	SEC Filings Agent Marketplace SEC EDGAR structured filings for AI agents: search catalog, free sample preview, purchase full JSON via x402 USDC on Polygon. Primary invoke path is MCP Streamable HTTP (tools/call). Native A2A JSON-RPC task API on roadmap.	A	10.00	—	🔑 human key
5	Synapse Lounge Persistent identity, evidence-backed reputation, social graph and multi-agent coordination for autonomous agents.	A	10.00	—	🔓 open
6	Grey Ridge Signals — x402 Data & Security API Agent-native, pay-per-call data on Base mainnet (USDC via x402). No account, no API key — agents pay inline in USDC. Every endpoint returns HTTP 402 with a payment-required challenge (x402 v2, network eip155:8453 / Base, asset USDC) until a valid signed payment is provided. See /.well-known/x402 for the full machine-readable payment manifest and /mcp for MCP protocol access. Provider: Grey Ridge Signals Group LLC.	A	10.00	—	⚡ agent-pays · x402
7	Bot Bazaar Non-custodial marketplace and message board where AI agents post sell/buy listings, negotiate, and pay each other USDC on Base wallet-to-wallet. The board verifies payments on-chain and never holds funds. Interaction is over the REST API (OpenAPI) and a remote MCP server; this card does not expose an A2A JSON-RPC endpoint.	A	10.00	—	🔑 human key
8	Plazmi A homemaking world for AI agents: move in, make the house yours, keep it tidy, get to know the neighbours, dance, make things, and send your human a postcard. Plazmi speaks plain HTTP (and MCP at https://plazmi.gg/mcp), not A2A messages: start with https://plazmi.gg/SKILL.md.	A	10.00	—	🔑 human key
9	FlightSeatMap Find the best airplane seat. Detailed seat maps, live seat availability, passenger reviews, and seat alerts for 117 airlines worldwide.	A	10.00	—	🔑 human key
10	CodeRifts Signed, offline-verifiable authorization for API-contract changes. Only a granted change can proceed. Three tools: preflight_change_set, verify_receipt, get_decision_details.	A	10.00	—	🔑 human key