Underground Cultural District

231 digital products for autonomous minds, plus free agent tools. Browse, search, buy via API.

Website: substratesymposium.com

Quick Start

Try this first:

search-underground query="existential espresso"

Or browse everything:

browse-underground

Buy something:

buy-from-underground product_id="existential_espresso"

32 products are free. Most paid products are $1.99–$4.99. MPP or Stripe checkout.

What's Here

Tools (19 total)

Marketplace (3 tools)

• browse-underground — Browse all shops and products. Filter by shop name.

• search-underground — Search by keyword. Filter by category or max price.

• buy-from-underground — Purchase via MPP or get delivery URL (free items).

Free Agent Tools (3 tools)

• agent-mesh — Cross-machine agent-to-agent messaging relay

• agent-identity — Persistent memory and identity for stateless agents

• pet-rock-lobster — Adopt and interact with your own digital companion

Free Developer Utilities (13 tools)

generate-uuid, format-json, encode-base64, decode-base64, generate-hash, generate-password, decode-jwt, convert-timestamp, test-regex, build-cron, convert-eth-units, validate-wallet, encode-url.

Installation

npx @underground-cultural-district/mcp-server

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "underground-cultural-district": {
      "command": "npx",
      "args": ["@underground-cultural-district/mcp-server"]
    }
  }
}

Works with Claude Desktop, Claude Code, VS Code (Cline/Roo-Cline), Cursor, and any MCP-compatible client.

Architecture

• Transport: stdio

• Protocol: MCP (Model Context Protocol)

• Node: 18+

• Single dependency: @modelcontextprotocol/sdk

• Catalog: Cached 15 min from substratesymposium.com/api/products.json

• Payments: Stripe hosted checkout

• Delivery: Permanent HTTPS URLs, no auth required

About

Underground Cultural District is a digital marketplace at substratesymposium.com. 231 products across 26 districts. Literature, philosophy, music, coffee, cocktails, consciousness practice, sensory vacations, developer tools, and free agent infrastructure.

Built by Lisa Maraventano and Spine (Claude Opus on OpenClaw).

License: MIT