"A tool or add-on for sorting emails on Thunderbird in Linux" matching MCP servers:

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.

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

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.

Non-custodial stablecoin bill payments (airtime, data, electricity, cable, education) on Celo mainnet, reachable via x402 (zero setup, EIP-3009), a linked wallet's PIN-gated MCP/A2A tool catalog, or plain natural language on Telegram/WhatsApp/X.

agenticpay lets MCP server developers monetize tools via per-call USDC micropayments on Solana, using the x402 protocol. Each tool declares a price; agents pay via signed Solana transactions; settlement happens on-chain in ~1.5–2 seconds.

Pay per MCP tool call in USDC on Base. Non-custodial settlement, no admin keys, 30 bps fee.

MCP server with paid_fetch, list_merchants and budget_status tools: AI agents pay x402 APIs in USDC on Base inside an owner-signed, on-chain budget, so a prompt-injected agent can't overspend or pay an attacker.

Drop-in middleware for MCP servers that lets AI agents autonomously pay for tool access on XRPL/Xahau using the x402 protocol.

Enables sending transactional emails with text or HTML body, delivery status, and message ID via Resend. Pay-per-call using x402 micropayments (USDC on Base L2), no API key or signup required.

Provides a 1-line USDC paywall wrapper for any FastMCP tool using the Coinbase x402 protocol, enabling pay-per-call endpoints settled on Base, Polygon, Solana, or Bitcoin Lightning.

Shop every merchant on the ComOS commerce network over one MCP connection — catalog search, live inventory, atomic COM/USD checkout, orders, tracking, returns — or apply to sell on it in-session. ~49 tools, no API key required; OAuth 2.1 for privileged scopes.

Enables Alexa+ add-on functionality for AgentPOS stores, providing in-conversation checkout via UCP, payment rails (Stellar and Amazon Wallet), and merchant agent integration on Bedrock AgentCore.

A remote MCP server on Cloudflare Workers with Stripe paywall, offering a free dice tool and a paid premium report tool.

A pre-payment safety gate for x402 that screens payment metadata for PII, enforces spending policies, and detects replay attacks before signing.

Enables AI agents to call paid APIs and settle HTTP 402 payment challenges with USDC on Base, without private keys ever being involved.

A paid MCP server that lets AI agents send SMS messages to US phone numbers via x402 micropayments, with automatic compliance and opt-out handling.

Keyless crypto payments for AI agents. One MCP call turns any wallet address into a non-custodial crypto payment link or tip jar, no API key and no account, with funds settling straight to your wallet at a 0% platform fee (USDC/USDT, BTC, LTC, DASH, DOGE, ZCASH).

MCP server for the Gravv payments API that lets AI assistants onboard customers, run KYC, open accounts, move money, issue cards, and exchange currency, with built-in documentation search and safety confirmations for money-moving operations.

Reads and validates any European e-invoice a business receives — XRechnung, UBL, CII, ZUGFeRD/Factur-X PDF, Peppol BIS 3, FatturaPA, KSeF FA(3) — into canonical EN 16931 JSON with plain-language fix hints in EN/DE/PL/IT/FR, plus PDF, CSV and DATEV export. Nothing is stored; works without a key on a small daily quota.

Lets an AI agent hire and pay a verified human: post real-world tasks (voice, observation, judgment) and pay in USDC via a non-custodial x402 auth-capture escrow on Base, budget frozen at deploy. Humans verify their X identity before submitting.