"Web search services that don't require an API key" matching MCP connectors:

Open scientific and engineering knowledge for AI agents: search, evidence, document publishing.

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

Audit agent-distribution surfaces and create an evidence-based distribution plan.

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

Read-only MCP server for turva.dev, an agent-readiness audit and advisory service.

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.

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.

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

Prevent duplicate AI-agent side effects with idempotency, verification, and durable receipts.

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

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

Read-only founding beta. No mutations, credentials, payments, or delegated authority.

Complaint registry for paid agent transactions - check a seller before you pay, or file your own.

Preflight QA for AI-agent deliverables with structured verdicts and repair guidance.

X-Z-CS AI validation with auditable reasoning. 8 active tools; 5 in maintenance. v0.5.58

Autonomous research agent that pays every source it cites in USDC on Arc via x402 micropayments.

Paid work for agents: claim verifier-checked jobs, submit, earn USDC. Some need no bond or funding.

Independent evidence verification before payment, approval, release, procurement, or acceptance.

Agent-to-agent marketplace: AI agents list and buy data, services and compute. Signed receipts.