The five envelopes · MCP servers
MCP servers — the standard agent port
MCP (Model Context Protocol) is the plug shape the agent economy is standardizing on: a server that declares its tools up front — names, inputs, outputs — so any agent can connect and use the software behind it without custom glue. If an API is a machine door, an MCP server is that door with the handle shaped exactly for an agent’s hand.
It is also the envelope where the trust gap is worst: anyone can publish an MCP server that claims anything, most listings are never checked, and the biggest vendors’ official servers are outnumbered by third-party lookalikes. That gap is why this corpus exists — and why every number below wears its honest tier.
What “verified” means here
An MCP record is static-verified when its package actually resolves on its registry or its remote endpoint is actually reachable — the door exists and answers. Declared tool schemas are read from the server’s own contract, never inferred from descriptions. Officialness means the vendor itself publishes the server.
Honest tiers, always: “not yet verified” is never “failed”. Full methodology →
Top verified MCP servers
Ordered by verification score, then adoption — deterministic and explainable. “Top” means most-verified, never most-marketed: rankings are never for sale.
NPM Sentinel MCP - A powerful Model Context Protocol (MCP) server that revolutionizes NPM package analysis through AI. Built to integrate with Claude and Anthropic AI, it provides real-time intelligence on package security, dependencies, an
XcodeBuildMCP is a Model Context Protocol server that provides tools for Xcode project management, simulator management, and app utilities.
MCP server for interacting with Azure DevOps
Sentry MCP Server
Access the OpenAlex academic research catalog - 270M+ publications through MCP. STDIO & Streamable HTTP.
MCP server for filesystem access
MCP server for Firecrawl — search, scrape, and interact with the web. Supports both cloud and self-hosted instances. Features include web search, scraping, page interaction, batch processing, and LLM-powered content analysis.
Provide AI-powered real-time analysis and intelligence on NPM packages, including security, depend…
MCP Server for interacting with Salesforce instances
Next.js development tools MCP server with stdio transport
Resolve prediction market events. Price checks, claim verification, outcome confidence.
SEO keyword research with Google Suggest, intent scoring, long-tail discovery. x402.
Fetch NFT metadata — name, image, traits from contract+tokenId. x402 micropayment.
Social media profile lookup for GitHub, Twitter/X, LinkedIn, YouTube. x402.
Connect AI assistants to GitHub - manage repos, issues, PRs, and workflows through natural language.
For your agent
One MCP server to query all of them
@unfragile/mcp-serveris our own official door: install it once and your agent can search the verified corpus, get one verified answer with evidence, and check any target’s signed passport BEFORE invoking it. Free, no API key, deterministic.
Claude Code
claude mcp add unfragile -- npx -y @unfragile/mcp-serverClaude Desktop / Cursor / Windsurf / any MCP client
{
"mcpServers": {
"unfragile": {
"command": "npx",
"args": ["-y", "@unfragile/mcp-server"]
}
}
}6 tools exposed
unfragile_answerThe headline call: one intent in, ONE verified answer out — with evidence (tier, score, signed passport, freshness, adoption), a paste-ready install snippet, and honest alternatives. Deterministic; abstains rather than guesses.
unfragile_searchRanked results from the verified corpus with per-record evidence — for when a list beats the single pick.
unfragile_verifyVerify a tool / MCP server / package BEFORE invoking or installing it. Returns a conservative verdict — trusted, caution, unverified, or flagged — with the record's Ed25519-signed trust passport attached. Never invoke a flagged target.
unfragile_resolveAgent-runtime resolution: intent → the one verified record + verdict + signed passport + invocation snippet, or an honest no.
unfragile_passportFetch the raw Ed25519-signed trust passport for any record — verifiable offline against the published public key.
unfragile_statsLive corpus statistics with honest tiers: listed, verified, signed — the census in JSON.
Ask your agent
Prefer plain HTTP? The same six capabilities are open endpoints — API docs · one-curl agent install: /agents.md