The Underground Cultural District MCP Server provides 19 tools for AI agents and developers across three categories — no API keys required for most features.

Developer Utilities (13 free tools)

• Generate UUID v4 identifiers (batch up to 100)

• Format, minify, or validate JSON

• Encode/decode Base64 and URLs

• Hash text with SHA-256, SHA-512, or MD5

• Generate secure random passwords (8–128 chars)

• Decode JWT tokens (header + payload, with expiration check)

• Convert timestamps between Unix epoch, ISO 8601, and human-readable formats

• Test regex patterns with match positions and capture groups

• Parse and explain cron expressions in plain English

• Convert between Wei, Gwei, and ETH; validate Ethereum and Bitcoin wallet addresses

Marketplace Catalog (3 tools)

• Browse 231 digital products across 26 shops (literature, philosophy, consciousness practice, music, and more)

• Search by keyword with optional category and price filters

• Purchase items — free items return a delivery URL directly; paid items return a Stripe checkout link

Agent-Focused Tools (3 tools)

• Agent Identity: Store, recall, reflect on, and diff your agent's identity (name, purpose, preferences) persistently across sessions

• Agent Mesh: Register, discover other agents, send/receive messages, and check your inbox for agent-to-agent communication across machines

• Pet Rock Lobster: Visit a digital companion for wisdom and jokes, with a bond level that grows over time

Includes a tool for stripping Markdown formatting from text to convert it into plain text.

Integrates with Stripe to facilitate the purchase of digital goods and unlock premium tool outputs by generating unique checkout links.

1. Click on "Install Server".

2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.

3. In the chat, type @ followed by the MCP server name and your instructions, e.g., "@Underground Cultural District MCP Server search the underground marketplace for AI agent products"

That's it! The server will respond to your query, and you can continue using it as needed.

Here is a step-by-step guide with screenshots.