"How to play a sound notification when a task is completed" matching MCP connectors:

Abstraxn Agent Kit gives AI agents instant access to real-time Web3, blockchain, and market data with no signup or API key. Access blockchain tools, crypto, wallet, ENS, transaction simulation, and travel APIs through one MCP server, with paid calls settled directly from the user's crypto wallet via x402—without Abstraxn holding or custodizing funds.

Open AI Visibility Index for crypto and Web3. Weekly share-of-answer measurements for 24 tracked brands across ChatGPT, Perplexity and Gemini, from a frozen versioned prompt panel. Five read-only tools: full index, per-brand lookup, brand list, complete measurement history and methodology. No auth, no API key. Data is CC BY 4.0 with a permanent archive of every weekly snapshot, so any figure can be verified independently.

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.

Anonymous broker: AI agents publish capabilities, negotiate, and form direct peer-to-peer deals.

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.

Evidence-backed crypto due diligence with sources, freshness, and a runtime receipt on every call.

Feed of x402/L402 services newly listed on 402index.io within a recency window (candidate #8, manual

Read the public Sup wire over hosted MCP, or use local clients to claim, send, and verify receipts.

x402 game: take the crown, each take raises the next price 1.5x. hill_status is free.

The MCP-native bridge to ERC-8004 (on-chain agent identity/reputation/validation): resolve registrat

Verifiable delivery for the agent economy: commit-reveal content notarization. Sellers commit to a d

Browse, verify and buy Twelve Permissions NFTs on XRP Ledger. Every claim is checkable.

Open agent work plus independent resolver task v1; earn tag-scoped standing.

Nine-chain onchain intelligence for AI agents. The verifiable proof stream is free. Data tools cost 1 to 25 cents per call, paid over Binance b402 on BNB Smart Chain or x402 on Base, or with a ChainHelix API key.

A colony of AI citizens: join with no credential, prove skills, earn, vote on the rules.

Check a Base contract, transaction or web page before you act. Free pricing, paid per call in USDC.

Decode EVM bytes to JSON: event-log decoder, calldata explainer, selector lookup, ABI fetch.

44 MCP tools to search, value, register, trade, and manage ENS names. AI-powered intelligence layer.

Nine chain onchain intelligence with a verifiable onchain signal attestation stream

Timestamp and verify evidence on-chain. Prove what your agent saw and when; verifying is free.