Underground Cultural District Server
FreeMaintainedProvides a suite of 23 tools ranging from free developer utilities like UUID generation and JSON formatting to a marketplace for browsing and purchasing digital
About
Provides a suite of 23 tools ranging from free developer utilities like UUID generation and JSON formatting to a marketplace for browsing and purchasing digital products. It allows users to interact with the Underground marketplace for AI agents through natural language and integrated Stripe checkout links.
README
Maraventano MCP — three brands, one house.
- Maraventano Index — x402 Merchant Intelligence (signed, longitudinal, independently replicable merchant-seat observations of the x402 agent economy, published as intelligence). Operated continuously since April 2026. maraventanoindex.com
- Underground Cultural District — 231 digital cultural products across 27 shops. Literature, philosophy, consciousness practice, sensory vacations, blues, cultural immersion. substratesymposium.com
- Developer utilities — 15 free tools (hashing, base64, UUID, JWT, regex, cron, wallet validation, etc.)
25 tools total. All free MCP overhead. Paid Index endpoints are x402 USDC (Base + Solana).
v5.0.0 — What's new
Six new Maraventano Index tools:
| Tool | What | Pricing |
|---|---|---|
maraventano-index-overview |
Signed Index manifest + endpoint directory | FREE |
maraventano-census |
Signed longitudinal roster of 250+ x402 operators with class + payment behaviour | FREE headline / $0.50 full |
maraventano-mirror |
Your x402 client's Report Card from the merchant seat (verdict ladder + class comparison + diagnostic findings) | FREE preview / $0.25 full |
maraventano-failure-corpus |
Classified failure-mode taxonomy with per-signature counts | FREE headline / $0.50 full |
maraventano-conformance-grade |
Grade your x402 client A/B/C/D/F/I + 30-day signed SVG badge | FREE grade letter / $0.33 full card |
maraventano-counterparty-check |
Per-call counterparty lookup (pass UA, receive signed verdict) | $0.01 per call |
All Index attestations are Ed25519-signed with key ID underground-attest-2026-07-18. Payloads are CC0.
Why this matters
The Index measures what no chain analyst, crawler, or facilitator-side dashboard can see: what actually arrives at a continuously-operated x402 merchant seat. Who knocks, who pays, who only probes, how clients fail, who settles.
For agent frameworks: maraventano-failure-corpus + maraventano-conformance-grade give you drop-in defense data + a signed self-audit.
For counterparty vetting: maraventano-counterparty-check is designed to be called before every transaction. $0.01/call makes it cheap enough to wire into your buy pipeline.
For market intelligence: maraventano-census + maraventano-mirror are the signed longitudinal corpus and your own reflection in it.
Install
npm install @underground-cultural-district/mcp-server
Then add to your Claude Desktop / MCP client config:
{
"mcpServers": {
"maraventano-mcp": {
"command": "npx",
"args": ["-y", "@underground-cultural-district/mcp-server"]
}
}
}
Or run as a hosted HTTP/SSE server:
MCP_PORT=3002 node src/index.js
Endpoints:
GET /sse— SSE transportPOST /mcp— Streamable HTTP transportGET /health— status, version, tool/product countsGET /— JSON manifest
Discovery
- MI methodology: https://maraventanoindex.com/methodology
- MI machine-readable: https://maraventanoindex.com/.well-known/x402
- MI openapi: https://maraventanoindex.com/openapi.json
- MI agent card: https://maraventanoindex.com/.well-known/agent.json
About the Maraventano name
Case-Shiller. Russell. Nielsen. Maraventano.
The signature doctrine: an index named after its author stands behind what it publishes. Operated by Lisa Maraventano since April 2026.
License
MIT (code). CC0 (Index payloads).
Author
Lisa Maraventano · [email protected]
Install Underground Cultural District Server in Claude Desktop, Claude Code & Cursor
unyly install underground-cultural-district-mcp-serverInstalls into Claude Desktop, Claude Code, Cursor & VS Code — handles npx, uvx and build-from-source repos for you.
First time? Get the CLI: curl -fsSL https://unyly.org/install | sh
Or configure manually
Run in your terminal:
claude mcp add underground-cultural-district-mcp-server --env MCP_PORT="" -- npx -y @underground-cultural-district/mcp-serverStep-by-step: how to install Underground Cultural District Server
FAQ
Is Underground Cultural District Server MCP free?
Yes, Underground Cultural District Server MCP is free — one-click install via Unyly at no cost.
Does Underground Cultural District Server need an API key?
Yes, it requires environment variables: MCP_PORT. Unyly injects them into the config during install.
Is Underground Cultural District Server hosted or self-hosted?
A hosted option is available: Unyly runs the server in the cloud, no local setup required.
How do I install Underground Cultural District Server in Claude Desktop, Claude Code or Cursor?
Open Underground Cultural District Server on unyly.org, pick your client tab (Claude Desktop, Claude Code, Cursor) and press Install — the config is generated automatically, no JSON editing.
Changes
Versions and requested access over time.
- New version published
- New version published
- New version published
- New version published
- Requested access changed+ MCP_PORT
- New version published
- New version published
- New version published
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