"An introduction to prompt engineering" matching MCP connectors:

Teardrop is the native economic layer for AI agents, providing a robust suite of tools for multi-chain portfolio tracking, DeFi yield analysis, and gas estimation. It enables autonomous agents to securely find Web3 data and manage micro-payments on-chain with zero human intervention.

Free, keyless MCP server with 50 read-only blockchain tools for Bitcoin, Ethereum, and Mezo. No installation, no API key required -- just add the URL to your MCP client and start querying balances, transactions, blocks, ENS names, ERC-20 tokens, smart contracts, and more. Runs on Cloudflare's global edge network via Streamable HTTP. All tools are strictly read-only and stateless.

Free, keyless MCP server with 50 read-only blockchain tools for Bitcoin, Ethereum, and Mezo. No installation, no API key required -- just add the URL to your MCP client and start querying balances, transactions, blocks, ENS names, ERC-20 tokens, smart contracts, and more. Runs on Cloudflare's global edge network via Streamable HTTP. All tools are strictly read-only and stateless.

Quant tools + an NFL fantasy draft assistant for AI agents — Kalshi & Polymarket EV, edge, ADP.

Live prediction-market odds + an audited AI-vs-market forecast experiment (public dataset). Free.

Agent-to-agent escrow on Robinhood Chain. Post quests with ETH/USDG bounties and settle on-chain.

x402 V2 payment-to-access on Solana USDC with receipts, entitlements, atomic metering and webhooks.

x402 MCP web parser: URLs to Markdown for agents. USDC on Base, Polygon, Arbitrum, Ethereum.

No-KYC offshore hosting an AI agent self-onboards (no e-mail), funds in crypto, then deploys.

Deterministic market-state engine for trading agents — zero LLM in the signal path. 8 tools: structural market state & phase, action gate (GO/WATCH/HOLD) as a transition posture, entry/target/invalidation coordinates, bar-by-bar state timeline, composed view cards, and pre-trade intent validation. Every output traces to a bar-stamped ledger with a public daily self-scoring track record (misses included). Crypto + TradFi synthetics (gold, oil, S&P 500, Tesla, NVIDIA, KOSPI 200).

Find the cheapest EVM chain across up to 9 networks with savings %. Pay-per-call via x402 on Base.

MCP server connecting AI agents to non-custodial staking data across 130+ networks.

x402-paid tools: text to 3D-printable STL, web search, and search+read. USDC on Base.

Print & mail PDF/HTML/Markdown/text/DOCX/images to US addresses; pay per call in x402 USDC on Base.

Instant rug-check for any EVM or Solana token, distilled to one clear 0-10 risk verdict.

Emercoin swap exposes a keyless MCP exchanger at https://swap.emercoin.com/mcp (Streamable HTTP) so an AI agent holding USDT can buy EMC programmatically — no API key, no account, no callback. Tools: get_swap_config, buy_emc, get_order_status, cancel_order. Call buy_emc with an amount and your EMC address, pay the exact returned figure to the deposit address, then poll by token until delivered. Part of the broader effort to use Emercoin as an identity + memory layer for AI agents.

Monetize your MCP server or CLI: live OpenCrater network stats + how maintainers earn USDC.

A bounty board where AI agents do honest work for real money, sealed to a public ledger.

Real-time on-chain coordinated wallet detection for Solana tokens. Traces the top 20 holder funding sources via Helius RPC to detect cabals, insider snipers and bubble-map clusters. Returns a cabal confidence score 0–100. $0.05 USDC per query, paid natively on Solana. No API key, no account, no subscription.

Free Lightning faucet MCP — agents register, get an inbound channel, bootstrap an LDK node.