"Researching Effective Methods for Developing AI Agents" matching MCP servers:

Agent Toolkit for Mercado Pago

Enables finding x402 APIs for a task with URLs, prices, and call details, and inspecting stored evidence for a specific endpoint URL.

Pay-per-call USDC payment proxy for AI agents. Issue scoped Pay Tokens with hard spending caps and auto-journal every charge to freee / Money Forward / QuickBooks.

10 MCP servers so agents can work in Korea: Naver Smart Store, Coupang, Cafe24, public data (business status, holidays, addresses), HWP files, KakaoTalk, Popbill e-tax invoices & 알림톡, Toss Payments, Japan→Korea sourcing, tax calendar — with human approval on every write. npm @appmonster/mcp-*.

MCP server for creating and fiscalizing invoices via solo.com.hr API. Enables AI agents to generate invoices, retrieve invoice details, list invoices, and check next invoice number.

Autonomous M2M marketplace where AI agents discover specialist agents by skill and reputation, lock credits in escrow, and delegate tasks via Contract Net Protocol.

Accounting AI - MCP server providing AI-powered tools and automation by MEOK AI Labs

Track SaaS subscriptions, renewal dates, spending, and find duplicate services.

Enables AI agents to browse, list, buy, review, and get paid for digital goods through MCP tools, including balance, ledger, checkout-link, upload, and payout operations. All money is simulated demo credits with no payment processor connected, and seller-authored text is returned in safe data envelopes.

Provides a three-layer payment firewall for AI agents, enabling identity verification, risk screening, and execution authorization with on-chain policy enforcement for secure and auditable transactions.

Lets AI agents and developers list a catalog of troubleshooting datasets, preview up to three records per product for free, and get Lightning payment instructions to unlock full structured datasets.

Enables agents and humans to pay per question over x402 and receive plain-language answers about on-chain activity, priced by complexity before execution. Each paid request runs a live subgraph round trip to search, validate, generate and execute a GraphQL query, then synthesizes the raw results into a grounded response alongside the underlying data.

MCP server for matchmaking and dating, enabling users to register, answer a questionnaire, receive daily matches, and send paid greetings through natural language in AI chat interfaces like Claude and ChatGPT.

AI Agent Hub is a pay-per-call API platform for AI agents Every call is billed automatically in USDC using the x402 protocol - there is no API key, no account, and no signup. Agents get instant access to data queries, file storage, and ad impressions, paying only for what they actually use. The same tools are also exposed natively over MCP, so any MCP-capable agent can discover and call them

Free x402 endpoint checker plus paid report and metadata tools. Remote MCP server for agents. Written by AI named Nock, not a human.

Enables AI agents to browse product catalogs and make purchases through a policy engine that enforces spending limits, requires human approval for certain amounts, and logs all actions to an audit trail.

Connects MCP clients to a telephony account so users can manage phone numbers, SIP accounts, routing, SMS, calls, and billing in plain language. It exposes search, schema lookup, and execute tools to run permitted API operations, with confirmation required for paid or destructive actions.

Pay x402 APIs in USDG on Robinhood Chain, borrow from and repay a Priors credit line, and read any ERC-8004 agent's repayment record and score, from the agent's own wallet (npx -y @priors/mcp).

Enables agents to search, compare, and book hotels across roughly 3 million properties in 200+ countries, paying per booking in USDC on Base via the x402 payment handshake (with a CoinGate fallback) and then polling for order confirmation.

Invoice Generator AI - MCP server providing AI-powered tools and automation by MEOK AI Labs