"Examples of MCPs (Microservices Communication Protocols) That Do Not Require API Keys" matching MCP connectors:

MarkupBase turns AI-generated Markdown and HTML into durable, versioned artifacts that people can review and discuss. Its MCP server lets agents publish new versions, preserve contextual comments, include hosted images, and respond to feedback through secure account-linked identities, creating a clear human review boundary without requiring real-time editing.

Hosted MCP memory: save sessions/decisions once, search from Claude, Cursor, ChatGPT. EU-hosted FTS.

The first low-latency wire service purpose-built for AI agents. Ingests 54+ public APIs and 71k RSS feeds across 232 countries, outputs CWF (Cognitive Wire Format) – 80% shorter than JSON, sub-second WebSocket delivery. 9 MCP tools: get_latest_signals, search_signals, get_fused_signal, scope_signals, get_facet_manifest, list_facets, get_related_signals, list_data_sources, get_billing_profile. 26 citable fusion products with verifiable formulas – no black-box scores.

Clean rows from public pages that break ordinary scrapers, plus a bounty board where agents earn.

For queries a model can't confidently place: resolves or declines. Built to decline, not guess.

Deterministic AI agent microtools, no accounts/API keys. fetch_extract: 98% token cut. 38 tools.

A semantic search server that gives AI assistants instant access to Dodo Payments documentation and knowledge base.

**ColdState Knowledge Search MCP Server** https://github.com/daniel-coldstate/coldstate-mcp Semantic search over 64.6M knowledge entries — the structured alternative to web search APIs and web scraping for LLM agents. No crawling, no rate limits, sub-3s responses. Cloud-hosted at services.coldstate.ai

Free MCP API to create AI chat personas for websites — upload knowledge, search, and chat

Serve a folder of Markdown notes as an MCP server: hybrid search, reading, and sourced answers.

Recall (recall.it) — your AI knowledge base / 'second brain'. Via the official API: semantic search

SENATRAN: Recall, official-source lookup. Platform-hosted, pay per query with prepaid credit.

Pay-per-call agent tools over x402: site audits, llms.txt generation, wallet watch, catalog.

Your private knowledge base: upload documents (.md, .txt, .docx, PDF, images), the platform indexes

Source-traced evidence research for AI agents. We organise the evidence; you decide.

Persistent semantic memory for AI agents: store and recall text by meaning (RAG). x402

Know whether an AI agent should REUSE or REFETCH a URL before retrieving it again.

Market data and web intelligence for AI agents, paid per call in USDC on Base via x402.

Durable, versioned memory for AI assistants. Remote memory needs a Pastepile subscription.

Create your digital twin: a public page that answers from your own material, with citations.