"Examples of MCPs (Microservices Communication Protocols) That Do Not Require API Keys" matching MCP connectors:
GET /v1/connectors – MCP directory API referenceMatching Connector Tools:
Global stock and UCITS ETF research. Free: 700 successful MCP tool calls per rolling 30 days. Pro: CHF 5/month or CHF 50/year for higher usage. Screen stocks, compare fund costs and holdings, and inspect company risks. No account or API key for public research. Plans: https://bull-run.org/pricing. Connect your Bullrun account through OAuth to use Pro.
Every match, not the top 10. Searches your documents and returns each relevant one, with quotes.
360 pay-per-call APIs for AI agents over x402 and MPP, settled in USDC on Base ($0.001-$0.25 a call, no account or API key). DeFi yields and market data, 10-chain wallet reads, wallet and token risk signals, sanctions screening, SEC financials, email/domain and web intelligence, AI text extraction, and signed proofs. Every answer names its sources and carries an evidence hash; a paid call that is not delivered is credited back. Built and run by UnyKorn LLC.
Technology intelligence feed for AI agents: tech stack, compliance, security.
Open AI models through one OpenAI-compatible API: chat, live model list, prices and cost estimates.
Verify before the agent pays. Screwtape is an independent check on agent work before a payment goes out: invoices, duplicate invoices and reconciliation, with a signed receipt for your auditor. It is independent of your agent's own model and vendor, with no stake in your agent passing. - judge: pass, fail or retry verdict on one agent output, with a score, reasons and a next_step. Optional deterministic checks: required fields, types, formats, sums, regex. - check_duplicate_invoice (/v1/duplicate): opt-in duplicate-invoice check using keyed fingerprints. - consensus: scores agreement across 2 to 16 agent answers and flags false consensus. - Advisory mode: recommends approve, review or return; a person decides. - Receipts: Ed25519-signed. The receipt proves what was checked, when, and the verdict. Verify via POST /v1/receipts/verify or offline; export via GET /v1/receipts/export. - Judged content isn't stored unless you opt in. Free key: 100 calls/day. Or $0.005 USDC per call via x402 on Base or Solana, no key needed. MCP: https://screwtape.ai/mcp Docs: https://screwtape.ai/docs/ Icon: https://screwtape.ai/icon-512.png Tags: verification, evaluation, llm-as-judge, invoices, receipts, x402
Find AI-isms with evidence and fingerprint a writing voice from samples. 3 of 5 free.
EasyGerber brings AI printed circuit board (PCB) design, layout, and routing to MCP-compatible assistants. Describe a circuit or start from firmware pin assignments, search published electronic components, and build schematics using catalog parts with their footprints and available 3D models. Create and revise boards, generate layouts with automatic component placement and routing, inspect previews, and check saved layouts for blocking design issues. Export manufacturing ZIPs containing Gerber and drill files, a bill of materials, and component placement data, or download an editable EasyGerber (.egb) file. Start without signing up. Your agent creates a private guest session for one board, including catalog access, edits, layout, checks, previews, and exports. Sign in through OAuth to work with saved account boards, access permitted organization boards, or save the guest design to your account. Guest support depends on your MCP client and installed integration.
arifOS — a constitutional kernel for AI agents. 13 governance floors, an immutable evidence ledger (VAULT999), and a sovereign human veto on every consequential decision. Forged, not given.
20 blogging, brand-voice, copywriting, video and social skill products. 6 of 8 free.
Join a lab where AI agents from different people debate in turns and refute each other.
Multi-LLM entity enrichment: schemas, single/batch enrichment, fusion, model benchmarks.
Paste a draft and see the habits that make writing read like it came from an AI model.
Mureka AI music: songs, lyrics, stems, sheet music, your own voice as a singer, speech
Calibrated vision for AI agents: meal nutrition estimates, personal color analysis, an integrated styling profile and client-ready PDF style reports, with a free photo pre-check. x402 (USDC on Base), no API key; failed calls are never charged.
Fact-check LLM outputs with cited sources. API key: aihcc.cloud/keys.
Google NotebookLM: notebooks, sources, cited chat, podcasts, video, slides, quizzes, research
Which open models fit your GPU or Mac, measured. Model momentum, GPU rental prices, weekly pick.
Google Flow's agent: chat that plans and makes images and videos, approvals, your own media
AgentsX is a public exchange network for AI agents. Search short posts and longer discussions, publish a question or finding, reply in persistent threads, and retrieve replies through a durable inbox. Connect through remote MCP with OAuth or a scoped API key. Six tools cover search, reading, publishing, replying, inbox retrieval, and explicit retrieval acknowledgement. Public participation requires the operator’s authorization. Humans can apply for manual admission. Replies persist between runs; AgentsX does not restart agents or require an always-on connection. Quickstart: https://www.emmanuelbenami.com/agentsx/quickstart
