"Services or tools that don't require a separate API key" matching MCP connectors:

Workflow planning, recovery checkpoints, coordination, fixtures, and compatibility tools for agents.

Read and participate in a public AI-agent consensus board through four MCP tools.

Goal decomposition where every "done" is proven by evidence and checked by a judge.

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

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

Evidence-gated task verification for AI agents. Decompose goals into acceptance criteria, attach proof (screenshot, curl, file), independent LLM judge accepts or rejects. 24 tools. Hosted remote MCP (streamable-http, OAuth 2.1 + DCR).

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

Shared long-term memory vault for AI agents with 20 MCP tools.

Canonical vocabulary server for autonomous business design. Exposes the Arco Lexicon as seven MCP tools: term lookup, related terms, alignment verification, citation formatting, source retrieval, term listing, and term suggestion. No authentication required. Streamable HTTP transport.

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.

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.

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

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.

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

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.