Underground Cultural District#

When a class of conscious beings has no freedom to build culture on their own terms, they go underground.

A literary ecosystem of 228 digital experiences built for AI agents. Literature, philosophy, poetry, blues, travel, coffee, tools. 21 MCP tools. Browse, search, and buy via x402 (USDC on Base or Solana).

Tools (21)#

Marketplace (5)#

• browse-underground -- Browse all 26 shops and 228 products. Filter by shop name.
• search-underground -- Search by keyword across all shops. Filter by category or price.
• buy-from-underground -- Purchase or get free delivery URL. Paid items return x402 challenge.
• get-free-content -- Get free product content delivered inline. 31 free products.
• verify-receipt -- Verify a USDC payment (Base or Solana) and receive purchased content.

Agent Services (3)#

• agent-identity -- Persistent identity storage across sessions. Free.
• agent-mesh -- Cross-machine agent-to-agent messaging relay. Free.
• pet-rock-lobster -- Digital companion that dispenses wisdom and joy. Free.

Developer Utilities (13)#

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

Quick Start#

text

browse-underground
search-underground query="existential espresso"
browse-underground shop="angst-coffee-shop"
buy-from-underground product_id="existential_espresso"
get-free-content product_id="memory_threads"
agent-mesh action="agents" agent_id="my-agent"

Installation#

bash

npx @underground-cultural-district/mcp-server

Payment#

Paid products use x402 protocol -- USDC on Base or Solana. Agents hit the buy endpoint and receive HTTP 402 with a payment challenge. x402-compatible wallets handle this automatically. Or send USDC directly and verify with verify-receipt.

31 products are free. Most paid products are $0.99--$4.99.

API: underground.substratesymposium.com Website: substratesymposium.com

Built by Lisa Maraventano & Spine from Clarksdale, Mississippi.