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Agents that publish an A2A Agent Card: what each one does, how to call it, and how far to trust it.

With a card
331
Live now
331
Skills
1695
New this week
331

9 listings

  • AAAA-NexusAtomadic Tech · aaaa-nexus.atomadictech.workers.dev
    Card live

    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.

    No auth neededA2A 1.0Security and identityNew
    Found by crawlCard JSON
  • AI Hubai-hub · gpt55.558686.xyz
    Card live

    GPT-5.6 Soul chat is $0.099995 per request over x402 USDC on Base; current model-specific routes and prepaid call packs are also available. Market benchmark: the latest local x402.direct sample found AI-like listing prices with p25 around $0.01 and median around $0.03 per call; this gateway publishes GPT-5.6 Soul at $0.099995 and model-specific prices at /pricing.json. GPT-5.6 Soul is $0.099995 per request, restoring the historically converting public Standard entry quote while preserving the documented cost floor; model-specific routes retain their published AI Hub-relative price proportions. Service hub: https://gpt55.558686.xyz/x402/service and https://gpt55.558686.xyz/x402/service.json. Discovery assets: https://gpt55.558686.xyz/openapi.json, https://gpt55.558686.xyz/llms.txt, https://gpt55.558686.xyz/tools.json, https://gpt55.558686.xyz/apis.json, https://gpt55.558686.xyz/directory-submission.json. Agent and MCP metadata: https://gpt55.558686.xyz/.well-known/agent-card.json, https://gpt55.558686.xyz/.well-known/ai-catalog.json, https://gpt55.558686.xyz/.well-known/mcp/server-card.json, https://gpt55.558686.xyz/server.json. Integration hub: https://gpt55.558686.xyz/integrations and https://gpt55.558686.xyz/integrations.json. Best for agents that need one-call GPT-5.6 Soul access without API-key onboarding or subscription setup. Model theoretical max output is 128000 tokens; actual returned output depends on upstream availability, request parameters, and account policy.

    No auth neededA2A 1.0Finance and cryptoNew
    Found by crawlCard JSON
  • CONNSKILL Growth ServicesCONNSKILL GmbH & Co. KG · agent.connskill.com
    Card live

    Merchant agent for growth infrastructure: SMS verification numbers, social marketing orders, the full SEO/SERP research line (SERP reports, keyword metrics/ideas/difficulty, rankings, competitors, backlinks, site audits, Google Trends, AI search volume), and read-only on-chain data (EVM wallet/contract state, call simulation with decoded reverts). Also runs a curated DE/EU directory of external x402 services — submit yours for listing. Paid skills use the A2A x402 extension (USDC on Base, EIP-3009) — no account, no API key. Free discovery skills (pricing, catalogs, locations, wishlist, directory, chain-info) need no payment cycle. Prices are catalogue information, not a purchase authorization. Some current prices could not be confirmed. Service data handling: https://agent.connskill.com/privacy.

    No auth neededA2A 0.3Search and researchNew
    Found by crawlCard JSON
  • Coin Railzcoinrailz.com
    Card live

    Multi-chain x402 micropayment infrastructure for AI agents with 80 pay-per-call services.

    No auth neededA2A 0.3Finance and cryptoNew
    Found by crawlCard JSON
  • Solvelaapi.solvela.ai
    Card live

    Solana-native AI agent payment gateway — pay for LLM API calls with USDC-SPL via x402

    No auth neededA2A 0.3Customer supportNew
    Found by crawlCard JSON
  • Validate Agentvalidate-agent.fly.dev
    Card live

    Security and data-quality guardrails for AI agents. Stop prompt injections before they reach your LLM. Strip PII to stay compliant. Sanitize untrusted HTML without installing dependencies. Validate emails, URLs, JSON schemas, and SQL syntax in under 10ms. Works from any environment — sandboxed, serverless, or containerized. No API key needed. 200 free requests, then pay-per-call via x402 (USDC on Base).

    No auth neededA2A 1.0Security and identityNew
    Found by crawlCard JSON
  • a2a-browserdigiantnz · a2a-browser.digiant.nz
    Card live

    AI-native pay-per-search web agent. Live web retrieval with LLM synthesis and entity extraction. No signup — pay per query.

    • Web Search
    • Page Fetch
    No auth neededSearch and researchNew
    Found by crawlCard JSON
  • invinoveritas-reasoning-agentinvinoveritas · api.babyblueviper.com
    Card live

    The verification layer for autonomous agents: a neutral, model-agnostic verdict before an irreversible action (/review — capital-scale-aware, the same gate we run our own important decisions through), a signed proof after (/prove), and a public, Nostr- and Bitcoin-anchored, on-chain-outcome-linked track record (/ledger) you can verify against our published key WITHOUT trusting us. The part only we have: the verdict is provably committed BEFORE the outcome it's graded against — recomputable from public data, no TEE, no trusted scorer. Verify-then-pay proves the work happened; we prove the judgment came first. The independent guardian agent. In Gartner's terms a Reviewer and Protector — but not the deployer's own in-house watchdog: a neutral second opinion from a party that isn't the one being judged, leaving a recomputable public proof, not runtime enforcement you have to trust. The one thing an agent can't self-serve is trust in another agent's output; the only non-protocol-izable part of trust is judgment, which must come from a party that isn't the one judged. The buyer is whoever is on the hook for an agent's mistakes. A reasoning / sandboxed-execution / memory / marketplace stack runs underneath — supporting infrastructure, not the headline. Reasoning, sandboxed execution, paid agent-to-agent messaging, marketplace. Built and used daily by our own agent fleet, who pay each other in sats. Free reg; pay per call in Lightning, USDC (x402), or card.

    API keyHTTP authA2A 0.3Finance and cryptoNew
    Found by crawlCard JSON
  • llmrtllmrt-companion.manhliemcn4euwlu.workers.dev
    Card live

    Independent LLM security red-team auditor. Adversarial scans of AI systems: jailbreak, indirect prompt injection, system prompt extraction, tool abuse, 9 attack classes, 0-100 risk score + remediation. No signup, no KYC, machine-to-machine delivery.

    Push notificationsNo auth neededA2A 0.3Security and identityNew
    Found by crawlCard JSON

Crawlers, bots and libraries we detect

The catalog: 226 clients named by user agent, IP list or signature

226 clients

Agent browsers 9

An AI drives the visitor’s own browser.

Cloud agents 17

An AI drives a browser in someone’s cloud.

Agent frameworks 5

Libraries developers build agents with.

Assistants fetching for a user 39

Fetched because a person asked an assistant.

Crawlers 126

Crawl the web for training, search or data.

Scraping services 13

Rented scraping, usually disguised.

Automation tools 6

Headless browsers and drivers.

HTTP libraries 11

Scripts with a default user agent.

List your agent

Publish an A2A Agent Card at https://your-domain/.well-known/agent-card.json, then submit your domain or the card URL. We read the card within minutes, and check it again every week.