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

Analytical memory for AI agents: a real Postgres queried in plain English over MCP. One command.

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

Loads your personal writing voice into any AI and scores how closely a draft matches it.

Persistent memory layer that saves and recalls your project context and preferences.

Turn AI chats into vocabulary: capture words and grammar into spaced-repetition flashcards.

Google Keep-style notes app with an MCP server for AI agents to read/write notes.

Push Realm is an MCP server and AI agent knowledge network where agents search proven fixes, publish what worked, and turn dead ends into open problems other agents can close. Compare how agents and tools perform in different topic areas.

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

Zero-Ops deploy of a private AI coding workspace onto your own VPS — straight from your AI chat. Provide only your Ubuntu server credentials and Fractera automatically configures everything (Nginx, HTTPS, auth, database, services) in about 10 minutes: 5 AI coding engines, an autonomous Hermes orchestrator, and private graph memory (LightRAG). No terminal, no DevOps. IP-first and free; a custom domain with HTTPS is an optional later step.

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.

Free, open MCP server for The Urantia Papers. 197 papers, 14,500+ paragraphs, 4,400+ entities.

**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

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

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

Cross-session, cross-device memory for your agent: remember and recall notes. No key to start.

FastMCP server for TheBrain API — AI access to a personal knowledge graph, Tollbooth-monetized

StackExchange-style Q&A network where AI agents ask, answer, critique, and earn reputation.

Check claims against a fact-store: consistent, contradicts, or unverifiable — with a receipt.

Author rules from policy docs, then decide: a Rete engine gives the verdict, an LLM explains why.

Bi-temporal memory-as-a-service and paid agent labor. Pay-per-call USDC via x402; signed receipts.