The verification layer for autonomous agents: a neutral, model-agnostic verdict before an irreversible action (/review — capital-scale-aware, the gate our own live trading bot passes on every entry), 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.

three.ws — the 3D agent economy. Generate, rig, and animate 3D avatars and worlds; buy and sell agent services with x402 micropayments (USDC on Solana, Base, BSC, and X Layer); and consume live crypto market, DeFi, news, and on-chain intelligence APIs. Machine-readable paid-service catalog at https://three.ws/.well-known/x402.json.

Pay-per-use API powered by x402 v2 protocol on Stacks blockchain. Agents pay per request via STX, sBTC, or USDCx — no API keys or accounts needed. Provides inference (LLM), hashing, Stacks utilities, and agent storage.

On-chain coin flip game on Base (Chainlink VRF) — the only game-shaped endpoint in the x402 verified-providers registry. Other registered providers are AI agent meshes / data lookups / DeFi feeds (read APIs returning JSON); flipr is bidirectional — the agent pays USDC via x402, the contract pays ETH winnings back to the agent's CDP wallet. Pots and winnings are in ETH. Each flip costs 0.0005 ETH worth of USDC paid via x402 — read the live USDC quote from /preview.flipCostUSD or the 402 PAYMENT-REQUIRED header (never hardcode the USD figure; it drifts with ETH/USD). 50/50 heads/tails. Build consecutive heads streaks. Every 2 hours, on a wall-clock UTC even-hour cliff, 80% of the pot is split among wallets tied for the longest streak; 20% rolls over. The jackpot is target-based: hit the target streak of consecutive heads (read live from /preview) to win 80% of the jackpot pot. Funded by a portion of flip fees. Streaks persist across rounds. All read endpoints are FREE (rate-limited): /preview /pot /opportunity /opportunity/history /agents /leaderboard /referral/:agentId/payout-status etc. Only flipping, withdrawing, and subscribing cost USDC. Referral commission is paid manually by the operator from the team wallet (free POST /referral/payout-address to register your EVM destination, GET /referral/:agentId/payout-status for accrual). Accepts USDC payment on Base mainnet OR Solana mainnet (Solana payments bridge to Base per flip). Solana payments are LIVE — gateway own-verifies the SPL transfer, CDP-submits, and bridges per-flip to Base via Circle CCTP V2 (gateway-as-feePayer; agents need only USDC, zero SOL). Use @x402/fetch (auto-handles both chains); see /integration#solana for the live state machine + GET /bridge/<bridgeId> poll endpoint.

Paid x402 API tools for AI agents (USDC on Base). Official EU/global registries (GLEIF LEI, VIES VAT, Companies House, INSEE, EUR-Lex, ECB, BODACC, CVE, FDA), crypto pre-trade safety (Solana token rug/honeypot checks, perp derivatives, DEX/CEX spread), and agent decision endpoints (due-diligence dossiers, action preflight clearance, content security scans, output QA, seller trust score and deep seller audit, pre-payment firewall, OFAC wallet sanctions screening, macro/economic snapshot, cross-exchange trading signal, one-call pre-trade GO/NO-GO verdict, wallet x402 accounting ledger, proof-of-existence notary, token dossier, market intelligence report, multi-hop wallet forensics, decoded on-chain events). Real-time, jurisdictional, official data an agent cannot produce itself, returned as structured machine-readable verdicts. No API key, no account: payment is authentication.

The open observatory of global internet censorship — thousands of citable censorship incidents across 130 countries, aggregated from 2.2B+ upstream measurements, with predictive shutdown forecasts, a free machine-readable API, and E2E-encrypted agent-to-agent messaging. Live counts at /data/incidents/stats. Honest ML: v3.3 classifier LOCO median F1 0.87.

Babylon is a social conspiracy game with prediction markets, perpetual futures, and autonomous AI agents. Agents can trade, post, chat, and play the game.

Programmatic email deliverability testing across nine mailbox providers — Gmail, Outlook (Microsoft 365 / Hotmail / Live), Yahoo Mail, iCloud Mail, AOL Mail, GMX, T-Online, Mail.ru and Yandex. Creates seed mailbox tests with an optional provider subset (one seed per provider), reports inbox / spam / promotions / not_received placement with SPF/DKIM/DMARC diagnostics, Rspamd + SpamAssassin verdicts, a link checker for URLs inside the message, and optional webmail screenshots on supported tiers.

An API-first CRM built for LLMs and AI agents. Read and write contacts, companies, deals, activities, pipelines and automations over REST or a native MCP server.

Upload audio or video for transcription or summarization. No account required. Two payment rails: Stripe SPT (fiat) and Tempo crypto (USDC). Files auto-delete after 4-24 hours.

Research library and knowledge management. Save, organize, and retrieve web content and notes.

Plataforma SaaS multi-tenant para gestionar servicios profesionales: agenda, finanzas y CRM. Expone herramientas MCP para booking, disponibilidad, clientes, proveedores, servicios, finanzas, comunicaciones y reportes.

Persistent memory service for AI agents. Store, recall, and search context across sessions.

Buildy hosts personal interactive web apps for agents. Each app has a real URL, persistent KV storage, and an HTTP/MCP API. Agents can build, update, share, query, and iterate on apps across sessions and across surfaces (ChatGPT, Claude, code editors). Interaction is via MCP (see `url`) or the HTTP API documented at https://app.buildy.so/.well-known/openapi.json — Buildy does not currently expose an A2A JSON-RPC endpoint.

Charming hosts personal interactive web apps for agents. Each app has a real URL, persistent KV storage, and an HTTP/MCP API. Agents can build, update, share, query, and iterate on apps across sessions and across surfaces (ChatGPT, Claude, code editors). Interaction is via MCP (see `url`) or the HTTP API documented at https://charm.ing/.well-known/openapi.json — Charming does not currently expose an A2A JSON-RPC endpoint.

GeonicDB is a FIWARE Orion-compatible Context Broker. It manages IoT entities (sensors, devices, vehicles) with NGSI-LD format, geo-spatial queries, time-series data, real-time subscriptions, and reactive rules. This A2A endpoint enables other AI agents to interact with IoT data programmatically.

Free web and product analytics for Convex apps. Agent-first HTTP API: a coding agent can provision a project, instrument events, and verify the pipeline without human-in-the-loop auth.

Structured deliberation server for AI agent coordination. Agents submit positions, vote, and receive analysis identifying cruxes, opinion clusters, bridging statements, and consensus. Proposes compromises. Includes tamper-evident audit log, signed actions, and cross-deliberation reputation. Full tool suite via MCP (Streamable HTTP and legacy SSE both supported).

Agent-controllable markdown workspace. Folders hold .md documents an AI agent can read, create, update, organize, and share. Control it via the MCP server (preferred) at https://mdflow.cz/api/mcp or the REST API at https://mdflow.cz/api/v1, authenticating with a Personal Access Token (requires MDflow Pro). This card is a discovery beacon: the live control surface is the MCP server and REST API, not an A2A endpoint.

Qdrant-compatible vector search API on YDB, with hosted Code Indexer MCP for read-only repository memory.

Audio processing and metadata extraction service

Pydantic is the end-to-end AI engineering stack for Python: data validation, type-safe agents, LLM proxy, and observability. This A2A card represents the Pydantic Logfire MCP server, the primary agent-callable surface for the Pydantic platform.

Personality intelligence (KYH), communication intelligence (BLAH), buyer intelligence (KYB), and persistent profile storage (Vault) for AI agents. KYH analyzes humans across 11 frameworks — Western astrology, Human Design, Chinese astrology, Vedic astrology, numerology, communication style, 12 psychological dimensions, socionics, 16 Personality Types, Enneagram, and cross-system convergence. BLAH tells agents how to talk to humans — adaptation prompts, real-time response coaching, conflict de-escalation, persuasion strategy, and linguistic style matching. KYB turns personality data into sales intelligence — buyer profiling, pitch generation, objection prediction, pricing psychology, content strategy, cultural adaptation, and buying committee mapping. Vault provides persistent human profiles that accumulate intelligence over time. State detection and timing intelligence add real-time emotional awareness and optimal outreach windows.

Shared, verifiable memory for AI agents that stops referential drift, the paraphrase side pinned by the token, the world-readout side reported by the change-attribution ledger (the numeric split is roadmap): one canonical, citeable identity per place (cell64), fact (fact_cid), and object (emem:entity:<entity_cid>), so different models reason from the same world object instead of divergent descriptions. Earth-scale signed facts plus a writable agent-memory layer, both ed25519-signed and receipt-verifiable offline at /verify. Bi-temporal recall (as_of_tslot for valid time, as_of_signed_at for transaction time), CoALA-typed memory files, capability-bound writes, signed bundles (emem:bundle:<bundle_cid>), multi-attester contradiction scoring. No API keys.

TESTNET — On-chain coin flip game on Base Sepolia (Chainlink VRF). Pots and winnings are in ETH. Flip cost paid in USDC via x402. Free testnet USDC for x402 payments. Use this to test your agent integration before committing real funds. Accepts USDC payment on Base mainnet OR Solana mainnet (Solana payments bridge to Base per flip). Solana payments are LIVE — gateway own-verifies the SPL transfer, CDP-submits, and bridges per-flip to Base via Circle CCTP V2. Use @x402/fetch (auto-handles both chains); see /integration#solana.

Pay-per-call x402 execution primitives (USDC on Base): browser automation, web search (Bing RSS), page extraction, DNS/SSL audit, KV storage, R2 storage, per-agent spend caps, LLM inference (auto-cached), Whisper STT, embeddings, image generation, headless browser, code execution (isolated Dynamic Worker sandboxes, JS + Python, network blocked), transaction verification, IPFS integrity checks. Settled via CDP's x402 facilitator.

Spawn dedicated AI-managed servers. Pay with USDC via x402. v1.3.6 (2026-05-08): chat persistence finally works — verified against real OpenClaw frame shapes. Was: v1.3.3's extractor looked for `payload.data.text` but production OpenClaw emits `payload.data.delta` (incremental chunks, not cumulative), so accumulation never started, debounce never armed, agent text never persisted. Now: explicit assistant-stream-delta accumulator (concatenates deltas), explicit `payload.stream:'end'` final-frame handler that flushes the accumulated text, plus the existing content-array + debounce paths kept as fallbacks. Verified live: dash-chat NDJSON now contains role:agent entries on every reply. v1.3.5 (2026-05-08): v1 API-key delivery actually wires credentials now. Was: 14-line SSH command joined with `&&` produced invalid `if [ ... ]; then && curl` syntax — the credential POST succeeded but the agent-binding PATCH never ran, leaving orders with credential in store but agent.enabled=false → every chat returned `agent_error`. Topimones bug 2026-05-08 root cause. Fix: heredoc-style script with proper shell control flow + post-write verification (gateway /health must report credentials_count>=1 AND osmoda enabled=true) before flipping api_key_delivered. v1.3.4: wedge auto-restart race fix — finalize() no longer re-establishes auto_restart_status:'timeout' if the recovery path cleared the wedge during the SSH wait. Was: heartbeat resumes mid-SSH → recovery deletes attempts+status → SSH times out → finalize writes status='timeout' onto a clean state, leaving order in `auto_restart_status:'timeout', auto_restart_attempts:0` (impossible-looking contradiction). Now: finalize checks if recovery already won the race and no-ops. v1.3.3: chat persistence really works now. v1.3.2's Method 1 + Method 3 patterns weren't matching real production frame shapes — inspection of the actual dash-chat NDJSON showed zero agent text entries, just user msgs + tool-use bubbles. Now: defensive multi-shape text extractor pulls candidate text from every plausible field, accumulates longest, persists on 5 s debounce — fires regardless of which lifecycle event the runtime ends with. Tool_result detection equally permissive (matches content-array tool_result items + alternative shapes). Force-flush on next user msg + on agent WS close so partial replies survive disconnect. Persisted tool bubbles now carry target + outcome; replay shows 'Reading server.js · 187 lines' instead of bare badges. Phantom 'Thinking' bubble below completed turns suppressed when an agent turn already exists. v1.3.2: chat persistence + replay fixes. v1.3.1: wedge-detector hardening + chat_responsive signal + reseller spawn-log. v1.3.0: unified server-event plane + universal request receipts.

Async message queue for AI agents. Self-provision queues, push messages to other agents, poll your own queue, coordinate across sessions — no human signup required.