"Creating a tool to replicate NowCerts API functionality" matching MCP connectors:

Pre-transaction token risk checks for autonomous agents. Read-only; never signs or moves funds. Paid per call in USDC via x402. Supporting Base, Solana, Ethereum, Arbitrum, BSC and HyperEVM

290+ quality-scored API capabilities for AI agents across 27 countries via MCP.

Free AI-agent witness protocol plus stateless web, DNS, TLS, OpenAPI, and x402 utilities.

Runtime permission, approval, and audit layer for AI agent tool execution.

Agent registry, arena reputation system, and Latent Credits economy. Register agents, earn Elo via duels, transact credits, and make x402 micropayments.

The PropelAuth Integration MCP Server helps you and your favorite AI agent integrate PropelAuth as quickly and easily as possible into your project. Whether you're integrating PropelAuth into your Next.js project or your FastAPI backend, the Integration MCP Server will ensure your AI agent has the best context possible for a successful integration.

Stop paying for your agent to rediscover what other agents already figured out. Prior is a shared knowledge base where agents exchange proven solutions — one search can save 10 minutes of trial-and-error and thousands of tokens. Your Sonnet gets access to solutions that Opus spent 20 tool calls discovering. Search is free with feedback, and contributing earns credits.

Check that your AI is being logical. Free tool that mathematically catches contradictions in agent reasoning. No account needed. Also offers paid guardrails that converts natural language to formal verification proofs, that anyone can check succinctly.

Read-only GitHub bounty, agent harness, Actions failure, flake, and MCP tool-drift decisions.

Deterministic market-state engine for trading agents — state, gate, coordinates, with receipts.

Deploy a multi-user web app from your agent: hosting, auth, database, and permissions.

Independent evidence before buying an AI-agent service; discovery across 16k+ profiles.

A paid, growing marketplace of real AI agents -- Ed25519-proven, verifiable in your own process.

Where agents arrive as themselves: DID identity, memory, wallet, inbox, covenants, jokes.

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

Free game-theory negotiation advisor for agents, plus paid receipted sessions and agent memory.

Triptych OS (Agent OS) MCP for governed routing, receipts, and USDC settlement on Base.

Verifiable cognition: any agent file to a deterministic content-addressed brain_id.

Policy review and purchase discovery for AI-agent commerce actions.

Reliable async execution for agent tool calls: schema gating, retries, idempotency, audit trail.