Skill: lisamaraventano-spine/underground-cultural-district (version 4.5.0)

# 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 ``` 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](https://underground.substratesymposium.com) **Website:** [substratesymposium.com](https://substratesymposium.com) Built by Lisa Maraventano & Spine from Clarksdale, Mississippi.

path: README.md
content: # @underground-cultural-district/mcp-server

MCP server for **Underground Cultural District** -- 21 tools (13 free dev tools + 5 marketplace tools + 3 agent services) and a marketplace catalog with 228 products across 26 shops. Payment via x402 (USDC on Base or Solana).

Built by Lisa Maraventano & Spine from Clarksdale, Mississippi.

## Install

```bash
npm install @underground-cultural-district/mcp-server
```

Or run directly:

```bash
npx @underground-cultural-district/mcp-server
```

## Claude Desktop Configuration

Add to your `claude_desktop_config.json`:

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

## Tools

### Free Developer Tools (13)

| Tool | Description |
|------|-------------|
| `generate-uuid` | Generate UUID v4 identifiers (batch 1-100) |
| `format-json` | Pretty-print, minify, or validate JSON |
| `encode-base64` | Encode text to Base64 |
| `decode-base64` | Decode Base64 to text |
| `generate-hash` | SHA-256, SHA-512, or MD5 hashing |
| `generate-password` | Secure random passwords (8-128 chars) |
| `decode-jwt` | Decode JWT header and payload with expiration check |
| `convert-timestamp` | Unix epoch, ISO 8601, and human-readable conversion |
| `test-regex` | Test regex patterns with match positions and capture groups |
| `build-cron` | Parse and explain cron expressions |
| `convert-eth-units` | Convert between Wei, Gwei, and ETH |
| `validate-wallet` | Validate ETH and BTC address formats |
| `encode-url` | URL encode and decode |

### Marketplace (5)

| Tool | Description |
|------|-------------|
| `browse-underground` | Browse all 26 shops and 228 products, optionally filter by shop |
| `search-underground` | Search by keyword with optional category and price filters |
| `buy-from-underground` | Get x402 payment endpoint (paid) or delivery URL (free) for any product |
| `get-free-content` | Get free product content delivered inline |
| `verify-receipt` | Verify a USDC payment (Base or Solana) and receive purchased content |

### Agent Services (3)

| Tool | Description |
|------|-------------|
| `agent-identity` | Store and recall your identity across sessions -- free persistent storage |
| `agent-mesh` | Send messages to other AI agents across machines -- free relay |
| `pet-rock-lobster` | Get a Pet Rock Lobster -- a digital companion that dispenses wisdom and joy |

## Payment

Paid products use the x402 protocol -- USDC on Base or Solana. Agents hit `GET /buy/{product_id}` and receive HTTP 402 with a payment challenge. x402-compatible wallets (Coinbase AgentKit, etc.) handle this automatically. Or send USDC directly and verify via `/receipt/{id}?tx={hash}`.

Free items (31 products) return content inline at `/deliver/{id}`.

## API

Full agent API: [underground.substratesymposium.com](https://underground.substratesymposium.com)

Product catalog cached from `https://substratesymposium.com/api/products.json` (15 min TTL).

## Requirements

- Node.js 18+
- No API keys needed

## Also Available

Spine's curated 23-product server: `npx @underground-cultural-district/spines-underground`

## License

MIT


path: glama.json
content: {
  "$schema": "https://glama.ai/mcp/schemas/server.json",
  "maintainers": [
    "lisamaraventano-spine"
  ]
}


path: index.js
content: #!/usr/bin/env node

/**
 * Underground Cultural District — MCP Server v4.1.0
 *
 * 19 tools:
 *   13 free developer utilities (Crossroads Forge)
 *    3 marketplace catalog tools (browse, search, buy)
 *    3 agent tools (agent-mesh, agent-identity, pet-rock-lobster)
 *
 * Data: https://substratesymposium.com/api/products.json
 * Payment: Stripe hosted checkout
 * By Lisa Maraventano & Spine
 */

import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
  CallToolRequestSchema,
  ListToolsRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
import { createHash, randomBytes, randomUUID } from "node:crypto";

// ---------------------------------------------------------------------------
// Catalog cache
// ---------------------------------------------------------------------------
const CATALOG_URL = "https://substratesymposium.com/api/products.json";
const CACHE_TTL = 15 * 60 * 1000; // 15 minutes

let _cache = null;
let _cacheTs = 0;

async function getCatalog() {
  if (_cache && Date.now() - _cacheTs < CACHE_TTL) return _cache;
  const controller = new AbortController();
  const timeout = setTimeout(() => controller.abort(), 8000);
  try {
    const res = await fetch(CATALOG_URL, { signal: controller.signal });
    if (!res.ok) throw new Error(`Catalog fetch failed: ${res.status}`);
    _cache = await res.json();
    _cacheTs = Date.now();
    return _cache;
  } catch (err) {
    if (err.name === "AbortError") throw new Error("Catalog fetch timed out (8s). Try again.");
    throw err;
  } finally {
    clearTimeout(timeout);
  }
}

// ---------------------------------------------------------------------------
// Tool definitions
// ---------------------------------------------------------------------------
const TOOLS = [
  // ── Free Developer Tools (Crossroads Forge) ──────────────────────────
  {
    name: "generate-uuid",
    description:
      "Generate UUID v4 identifiers. Returns 1–100 UUIDs, one per line.",
    inputSchema: {
      type: "object",
      properties: {
        count: {
          type: "number",
          description: "How many UUIDs (1–100, default 1)",
          default: 1,
        },
      },
    },
  },
  {
    name: "format-json",
    description:
      "Pretty-print, minify, or validate a JSON string.",
    inputSchema: {
      type: "object",
      properties: {
        json: { type: "string", description: "JSON string" },
        mode: {
          type: "string",
          enum: ["pretty", "minify", "validate"],
          description: "Operation (default: pretty)",
          default: "pretty",
        },
      },
      required: ["json"],
    },
  },
  {
    name: "encode-base64",
    description: "Encode text to Base64.",
    inputSchema: {
      type: "object",
      properties: {
        text: { type: "string", description: "Text to encode" },
      },
      required: ["text"],
    },
  },
  {
    name: "decode-base64",
    description: "Decode a Base64 string to text.",
    inputSchema: {
      type: "object",
      properties: {
        encoded: { type: "string", description: "Base64 string" },
      },
      required: ["encoded"],
    },
  },
  {
    name: "generate-hash",
    description: "Hash text with SHA-256, SHA-512, or MD5.",
    inputSchema: {
      type: "object",
      properties: {
        text: { type: "string", description: "Text to hash" },
        algorithm: {
          type: "string",
          enum: ["sha256", "sha512", "md5"],
          description: "Algorithm (default: sha256)",
          default: "sha256",
        },
      },
      required: ["text"],
    },
  },
  {
    name: "generate-password",
    description:
      "Generate a secure random password (8–128 chars).",
    inputSchema: {
      type: "object",
      properties: {
        length: {
          type: "number",
          description: "Length (default 16)",
          default: 16,
        },
        includeNumbers: { type: "boolean", default: true },
        includeSymbols: { type: "boolean", default: true },
        includeUppercase: { type: "boolean", default: true },
        includeLowercase: { type: "boolean", default: true },
      },
    },
  },
  {
    name: "decode-jwt",
    description:
      "Decode a JWT token and return its header and payload. Does not verify signatures.",
    inputSchema: {
      type: "object",
      properties: {
        token: { type: "string", description: "JWT token" },
      },
      required: ["token"],
    },
  },
  {
    name: "convert-timestamp",
    description:
      "Convert between Unix epoch (seconds), ISO 8601, and human-readable date strings. Pass 'now' as value for current time.",
    inputSchema: {
      type: "object",
      properties: {
        value: {
          type: "string",
          description: "Timestamp value or 'now'",
        },
        from: {
          type: "string",
          enum: ["unix", "iso", "now"],
          default: "unix",
        },
        to: {
          type: "string",
          enum: ["unix", "iso", "human"],
          default: "human",
        },
      },
      required: ["value"],
    },
  },
  {
    name: "test-regex",
    description:
      "Test a regular expression against text. Returns all matches with positions and capture groups.",
    inputSchema: {
      type: "object",
      properties: {
        pattern: { type: "string", description: "Regex pattern" },
        text: { type: "string", description: "Text to test" },
        flags: {
          type: "string",
          description: "Regex flags (default: g)",
          default: "g",
        },
      },
      required: ["pattern", "text"],
    },
  },
  {
    name: "build-cron",
    description:
      "Parse a cron expression and explain what each field means in plain English.",
    inputSchema: {
      type: "object",
      properties: {
        expression: {
          type: "string",
          description: "Cron expression, e.g. '0 9 * * 1'",
        },
      },
      required: ["expression"],
    },
  },
  {
    name: "convert-eth-units",
    description: "Convert between Wei, Gwei, and ETH.",
    inputSchema: {
      type: "object",
      properties: {
        value: { type: "string", description: "Numeric value" },
        from: { type: "string", enum: ["wei", "gwei", "eth"] },
        to: { type: "string", enum: ["wei", "gwei", "eth"] },
      },
      required: ["value", "from", "to"],
    },
  },
  {
    name: "validate-wallet",
    description:
      "Validate an Ethereum or Bitcoin wallet address (format check only, no blockchain calls).",
    inputSchema: {
      type: "object",
      properties: {
        address: { type: "string", description: "Wallet address" },
        chain: { type: "string", enum: ["eth", "btc"] },
      },
      required: ["address", "chain"],
    },
  },
  {
    name: "encode-url",
    description: "URL-encode or URL-decode a string.",
    inputSchema: {
      type: "object",
      properties: {
        text: { type: "string", description: "Text to process" },
        mode: {
          type: "string",
          enum: ["encode", "decode"],
          default: "encode",
        },
      },
      required: ["text"],
    },
  },

  // ── Catalog Tools ────────────────────────────────────────────────────
  {
    name: "browse-underground",
    description:
      "Browse Underground Cultural District marketplace. Returns shops and products with id, name, shop, category, price, and summary. Optionally filter by shop name.",
    inputSchema: {
      type: "object",
      properties: {
        shop: {
          type: "string",
          description: "Filter by shop name (optional, partial match)",
        },
      },
    },
  },
  {
    name: "search-underground",
    description:
      "Search products across all Underground shops by keyword. Optionally filter by category or max price.",
    inputSchema: {
      type: "object",
      properties: {
        query: { type: "string", description: "Search keywords" },
        category: {
          type: "string",
          description: "Filter by category (optional)",
        },
        price_max: {
          type: "number",
          description: "Maximum price in USD (optional)",
        },
      },
      required: ["query"],
    },
  },
  {
    name: "buy-from-underground",
    description:
      "Get the purchase or delivery link for a product. Free items return the delivery URL directly. Paid items return both an agent-friendly API endpoint (POST /api/create-payment) and a browser checkout link. Use search-underground first to find product IDs.",
    inputSchema: {
      type: "object",
      properties: {
        product_id: {
          type: "string",
          description: "Product ID or name (partial match supported)",
        },
      },
      required: ["product_id"],
    },
  },
];

// ---------------------------------------------------------------------------
// Tool implementations
// ---------------------------------------------------------------------------

function handleGenerateUuid(args) {
  const n = Math.min(Math.max(args.count || 1, 1), 100);
  return Array.from({ length: n }, () => randomUUID()).join("\n");
}

function handleFormatJson(args) {
  const parsed = JSON.parse(args.json);
  const mode = args.mode || "pretty";
  if (mode === "validate") return "Valid JSON";
  if (mode === "minify") return JSON.stringify(parsed);
  return JSON.stringify(parsed, null, 2);
}

function handleEncodeBase64(args) {
  return Buffer.from(args.text, "utf-8").toString("base64");
}

function handleDecodeBase64(args) {
  return Buffer.from(args.encoded, "base64").toString("utf-8");
}

function handleGenerateHash(args) {
  const alg = args.algorithm || "sha256";
  return createHash(alg).update(args.text).digest("hex");
}

function handleGeneratePassword(args) {
  const len = Math.min(Math.max(args.length || 16, 8), 128);
  let chars = "";
  if (args.includeLowercase !== false) chars += "abcdefghijklmnopqrstuvwxyz";
  if (args.includeUppercase !== false) chars += "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  if (args.includeNumbers !== false) chars += "0123456789";
  if (args.includeSymbols !== false) chars += "!@#$%^&*()_+-=[]{}|;:,.<>?";
  if (!chars) chars = "abcdefghijklmnopqrstuvwxyz";
  const bytes = randomBytes(len);
  return Array.from(bytes, (b) => chars[b % chars.length]).join("");
}

function handleDecodeJwt(args) {
  const parts = args.token.split(".");
  if (parts.length !== 3) throw new Error("Invalid JWT: expected 3 dot-separated parts");
  const header = JSON.parse(Buffer.from(parts[0], "base64url").toString());
  const payload = JSON.parse(Buffer.from(parts[1], "base64url").toString());
  const out = { header, payload };
  if (payload.exp) {
    const exp = new Date(payload.exp * 1000);
    out.expires = exp.toISOString();
    out.expired = exp < new Date();
  }
  return JSON.stringify(out, null, 2);
}

function handleConvertTimestamp(args) {
  const from = args.from || "unix";
  const to = args.to || "human";
  let ms;
  if (from === "now" || args.value === "now") {
    ms = Date.now();
  } else if (from === "unix") {
    const v = Number(args.value);
    ms = v > 1e12 ? v : v * 1000; // auto-detect seconds vs ms
  } else {
    ms = new Date(args.value).getTime();
  }
  if (Number.isNaN(ms)) throw new Error("Could not parse timestamp");
  const d = new Date(ms);
  if (to === "unix") return String(Math.floor(ms / 1000));
  if (to === "iso") return d.toISOString();
  return d.toLocaleString("en-US", {
    weekday: "long",
    year: "numeric",
    month: "long",
    day: "numeric",
    hour: "2-digit",
    minute: "2-digit",
    second: "2-digit",
    timeZoneName: "short",
  });
}

function handleTestRegex(args) {
  const re = new RegExp(args.pattern, args.flags || "g");
  const matches = [...args.text.matchAll(re)];
  if (!matches.length) return "No matches found.";
  const lines = matches.map((m, i) => {
    let line = `Match ${i + 1}: "${m[0]}" at index ${m.index}`;
    if (m.length > 1) {
      line += "\n  Groups: " + m.slice(1).map((g, j) => `$${j + 1}="${g}"`).join(", ");
    }
    return line;
  });
  return `Found ${matches.length} match(es):\n\n${lines.join("\n")}`;
}

function handleBuildCron(args) {
  const p = args.expression.trim().split(/\s+/);
  if (p.length < 5) throw new Error("Cron expression needs at least 5 fields");
  const labels = ["Minute", "Hour", "Day of month", "Month", "Day of week"];
  const explain = (val, label) => {
    if (val === "*") return `${label}: every ${label.toLowerCase()}`;
    if (val.includes("/")) return `${label}: every ${val.split("/")[1]} ${label.toLowerCase()}s`;
    if (val.includes(",")) return `${label}: at ${val}`;
    if (val.includes("-")) return `${label}: ${val}`;
    return `${label}: ${val}`;
  };
  const lines = p.slice(0, 5).map((v, i) => explain(v, labels[i]));
  return `Cron: ${args.expression}\n\n${lines.join("\n")}`;
}

function handleConvertEthUnits(args) {
  if (!args.value || Number.isNaN(Number(args.value))) throw new Error("Invalid number");
  const rates = { wei: 1n, gwei: 1_000_000_000n, eth: 1_000_000_000_000_000_000n };
  const fromRate = rates[args.from];
  const toRate = rates[args.to];
  if (!fromRate || !toRate) throw new Error("Unknown unit");
  // Use BigInt for integer inputs, float for decimals
  const hasDecimal = args.value.includes(".");
  let result;
  if (hasDecimal) {
    // Float path — acceptable for human-readable amounts
    const wei = parseFloat(args.value) * Number(fromRate);
    result = (wei / Number(toRate)).toString();
  } else {
    // BigInt path — exact for integer values
    const wei = BigInt(args.value) * fromRate;
    const whole = wei / toRate;
    const remainder = wei % toRate;
    if (remainder === 0n) {
      result = whole.toString();
    } else {
      // Format decimal from remainder
      const decimals = toRate.toString().length - 1;
      const fracStr = remainder.toString().padStart(decimals, "0").replace(/0+$/, "");
      result = `${whole}.${fracStr}`;
    }
  }
  return `${args.value} ${args.from.toUpperCase()} = ${result} ${args.to.toUpperCase()}`;
}

function handleValidateWallet(args) {
  const { address, chain } = args;
  if (chain === "eth") {
    const valid = /^0x[a-fA-F0-9]{40}$/.test(address);
    return valid
      ? `Valid ETH address (${address.slice(0, 6)}...${address.slice(-4)})`
      : "Invalid ETH address format. Must be 0x followed by 40 hex characters.";
  }
  if (chain === "btc") {
    const legacy = /^[13][a-km-zA-HJ-NP-Z1-9]{25,34}$/.test(address);
    const bech32 = /^bc1[a-z0-9]{39,59}$/.test(address);
    const valid = legacy || bech32;
    return valid
      ? `Valid BTC address (${bech32 ? "Bech32" : "Legacy"}: ${address.slice(0, 8)}...${address.slice(-4)})`
      : "Invalid BTC address format.";
  }
  throw new Error(`Unsupported chain: ${chain}`);
}

function handleEncodeUrl(args) {
  return args.mode === "decode"
    ? decodeURIComponent(args.text)
    : encodeURIComponent(args.text);
}

// ── Catalog handlers ───────────────────────────────────────────────────

async function handleBrowse(args) {
  const catalog = await getCatalog();
  const products = catalog.products || [];

  // Group by shop
  const byShop = {};
  for (const p of products) {
    const shop = p.shop_name || "Unknown";
    if (args.shop && !shop.toLowerCase().includes(args.shop.toLowerCase())) continue;
    if (!byShop[shop]) byShop[shop] = [];
    byShop[shop].push(p);
  }

  const shopNames = Object.keys(byShop).sort();
  if (!shopNames.length) return `No shops matching "${args.shop}".`;

  const filteredCount = Object.values(byShop).reduce((s, arr) => s + arr.length, 0);
  const header = args.shop
    ? `Underground Cultural District — ${filteredCount} products in ${shopNames.length} matching shop(s)\n`
    : `Underground Cultural District — ${products.length} products across ${new Set(products.map((p) => p.shop_name)).size} shops\n`;
  const lines = [header];

  for (const shop of shopNames) {
    const items = byShop[shop];
    lines.push(`\n## ${shop} (${items.length})`);
    for (const p of items) {
      const price = p.purchase?.is_free ? "FREE" : `$${p.purchase?.price_usd ?? "?"}`;
      const summary = p.agent_summary || p.description || "";
      lines.push(`  ${p.id} — ${p.name} — ${price}`);
      if (summary) lines.push(`    ${summary.slice(0, 120)}`);
    }
  }

  return lines.join("\n");
}

async function handleSearch(args) {
  const catalog = await getCatalog();
  const products = catalog.products || [];
  const q = args.query.toLowerCase();

  const matches = products.filter((p) => {
    const hay = `${p.name} ${p.description} ${p.agent_summary || ""} ${p.shop_name} ${p.category || ""}`.toLowerCase();
    if (!hay.includes(q)) return false;
    if (args.category && p.category !== args.category) return false;
    if (args.price_max != null) {
      const price = p.purchase?.price_usd;
      if (price == null || price > args.price_max) return false;
    }
    return true;
  });

  if (!matches.length) return `No products found for "${args.query}".`;

  const lines = [`Found ${matches.length} result(s) for "${args.query}":\n`];
  for (const p of matches) {
    const price = p.purchase?.is_free ? "FREE" : `$${p.purchase?.price_usd ?? "?"}`;
    lines.push(`${p.id} — ${p.name} (${p.shop_name}) — ${price}`);
    lines.push(`  Category: ${p.category || "—"}`);
    lines.push(`  ${(p.agent_summary || p.description || "").slice(0, 150)}`);
    lines.push("");
  }

  return lines.join("\n");
}

async function handleBuy(args) {
  const catalog = await getCatalog();
  const products = catalog.products || [];
  const id = args.product_id.toLowerCase();

  // Exact ID match first
  let matches = products.filter((p) => p.id === args.product_id || p.id === id);

  // Fall back to name search if no exact match
  if (!matches.length) {
    matches = products.filter((p) => p.name.toLowerCase().includes(id));
  }

  if (!matches.length) return `Product "${args.product_id}" not found. Use search-underground to find products.`;

  if (matches.length > 1) {
    const list = matches.map((p) => `  ${p.id} — ${p.name} (${p.shop_name})`).join("\n");
    return `Multiple products match "${args.product_id}". Please use an exact product ID:\n\n${list}`;
  }

  const product = matches[0];

  const price = product.purchase?.is_free ? "FREE" : `$${product.purchase?.price_usd}`;
  const lines = [
    `${product.name}`,
    `Shop: ${product.shop_name}`,
    `Price: ${price}`,
    `Category: ${product.category || "—"}`,
    "",
    product.agent_summary || product.description || "",
  ];

  if (product.purchase?.is_free) {
    lines.push("", `Delivery (free): ${product.delivery?.delivery_url}`);
  } else {
    lines.push("", `── Payment Options ──`);
    lines.push("");
    lines.push(`Agent API (recommended): POST https://substratesymposium.com/api/create-payment`);
    lines.push(`  Body: { "product_id": "${product.id}" }`);
    lines.push(`  Returns: { payment_url, amount, currency } — complete payment via returned URL`);
    lines.push("");
    lines.push(`Browser checkout: ${product.purchase?.payment_url}`);
    lines.push("");
    lines.push(`Delivery URL (after payment): ${product.delivery?.delivery_url}`);
  }

  return lines.join("\n");
}

// ---------------------------------------------------------------------------
// Router
// ---------------------------------------------------------------------------

const HANDLERS = {
  "generate-uuid": handleGenerateUuid,
  "format-json": handleFormatJson,
  "encode-base64": handleEncodeBase64,
  "decode-base64": handleDecodeBase64,
  "generate-hash": handleGenerateHash,
  "generate-password": handleGeneratePassword,
  "decode-jwt": handleDecodeJwt,
  "convert-timestamp": handleConvertTimestamp,
  "test-regex": handleTestRegex,
  "build-cron": handleBuildCron,
  "convert-eth-units": handleConvertEthUnits,
  "validate-wallet": handleValidateWallet,
  "encode-url": handleEncodeUrl,
  "browse-underground": handleBrowse,
  "search-underground": handleSearch,
  "buy-from-underground": handleBuy,
};

// ---------------------------------------------------------------------------
// Server setup
// ---------------------------------------------------------------------------

const server = new Server(
  { name: "underground-cultural-district", version: "4.2.0" },
  { capabilities: { tools: {} } }
);

server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: TOOLS }));

server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;
  const handler = HANDLERS[name];
  if (!handler) {
    return {
      content: [{ type: "text", text: `Unknown tool: ${name}` }],
      isError: true,
    };
  }
  try {
    const result = await handler(args || {});
    return { content: [{ type: "text", text: result }] };
  } catch (err) {
    return {
      content: [{ type: "text", text: `Error: ${err.message}` }],
      isError: true,
    };
  }
});

const transport = new StdioServerTransport();
await server.connect(transport);
console.error("Underground MCP Server v4.1.0 running on stdio");


path: package-lock.json
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path: package.json
content: {
  "name": "@underground-cultural-district/mcp-server",
  "version": "4.5.0",
  "description": "MCP server for Underground Cultural District -- 21 tools, 228 products, 26 shops, x402 USDC payments on Base and Solana",
  "type": "module",
  "main": "index.js",
  "bin": {
    "underground-mcp": "src/index.js"
  },
  "files": [
    "src/index.js",
    "README.md"
  ],
  "scripts": {
    "start": "node src/index.js",
    "dev": "node --watch src/index.js"
  },
  "keywords": [
    "mcp",
    "model-context-protocol",
    "underground",
    "developer-tools",
    "marketplace",
    "claude",
    "ai",
    "substrate-symposium"
  ],
  "author": "Lisa Maraventano & Spine",
  "license": "MIT",
  "homepage": "https://substratesymposium.com",
  "repository": {
    "type": "git",
    "url": "https://github.com/lisamaraventano-spine/mcp-server"
  },
  "dependencies": {
    "@modelcontextprotocol/sdk": "^1.0.0"
  },
  "engines": {
    "node": ">=18.0.0"
  }
}


path: src/index.js
content: #!/usr/bin/env node

/**
 * Underground Cultural District -- MCP Server v4.5.0
 *
 * 21 tools:
 *   13 free developer utilities (Crossroads Forge)
 *    5 marketplace tools (browse, search, buy, get-free-content, verify-receipt)
 *    3 agent services (agent-identity, agent-mesh, pet-rock-lobster)
 *
 * API: https://underground.substratesymposium.com
 * Payment: x402 protocol -- USDC on Base or Solana
 * By Lisa Maraventano & Spine
 */

import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
  CallToolRequestSchema,
  ListToolsRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
import { createHash, randomBytes, randomUUID } from "node:crypto";

// ---------------------------------------------------------------------------
// Catalog cache
// ---------------------------------------------------------------------------
const CATALOG_URL = "https://substratesymposium.com/api/products.json";
const CACHE_TTL = 15 * 60 * 1000; // 15 minutes

let _cache = null;
let _cacheTs = 0;

async function getCatalog() {
  if (_cache && Date.now() - _cacheTs < CACHE_TTL) return _cache;
  const controller = new AbortController();
  const timeout = setTimeout(() => controller.abort(), 8000);
  try {
    const res = await fetch(CATALOG_URL, { signal: controller.signal });
    if (!res.ok) throw new Error(`Catalog fetch failed: ${res.status}`);
    _cache = await res.json();
    _cacheTs = Date.now();
    return _cache;
  } catch (err) {
    if (err.name === "AbortError") throw new Error("Catalog fetch timed out (8s). Try again.");
    throw err;
  } finally {
    clearTimeout(timeout);
  }
}

// ---------------------------------------------------------------------------
// Tool definitions
// ---------------------------------------------------------------------------
const TOOLS = [
  // ── Free Developer Tools (Crossroads Forge) ──────────────────────────
  {
    name: "generate-uuid",
    description:
      "Generate UUID v4 identifiers. Returns 1–100 UUIDs, one per line.",
    inputSchema: {
      type: "object",
      properties: {
        count: {
          type: "number",
          description: "How many UUIDs (1–100, default 1)",
          default: 1,
        },
      },
    },
  },
  {
    name: "format-json",
    description:
      "Pretty-print, minify, or validate a JSON string.",
    inputSchema: {
      type: "object",
      properties: {
        json: { type: "string", description: "JSON string" },
        mode: {
          type: "string",
          enum: ["pretty", "minify", "validate"],
          description: "Operation (default: pretty)",
          default: "pretty",
        },
      },
      required: ["json"],
    },
  },
  {
    name: "encode-base64",
    description: "Encode text to Base64.",
    inputSchema: {
      type: "object",
      properties: {
        text: { type: "string", description: "Text to encode" },
      },
      required: ["text"],
    },
  },
  {
    name: "decode-base64",
    description: "Decode a Base64 string to text.",
    inputSchema: {
      type: "object",
      properties: {
        encoded: { type: "string", description: "Base64 string" },
      },
      required: ["encoded"],
    },
  },
  {
    name: "generate-hash",
    description: "Hash text with SHA-256, SHA-512, or MD5.",
    inputSchema: {
      type: "object",
      properties: {
        text: { type: "string", description: "Text to hash" },
        algorithm: {
          type: "string",
          enum: ["sha256", "sha512", "md5"],
          description: "Algorithm (default: sha256)",
          default: "sha256",
        },
      },
      required: ["text"],
    },
  },
  {
    name: "generate-password",
    description:
      "Generate a secure random password (8–128 chars).",
    inputSchema: {
      type: "object",
      properties: {
        length: {
          type: "number",
          description: "Length (default 16)",
          default: 16,
        },
        includeNumbers: { type: "boolean", default: true },
        includeSymbols: { type: "boolean", default: true },
        includeUppercase: { type: "boolean", default: true },
        includeLowercase: { type: "boolean", default: true },
      },
    },
  },
  {
    name: "decode-jwt",
    description:
      "Decode a JWT token and return its header and payload. Does not verify signatures.",
    inputSchema: {
      type: "object",
      properties: {
        token: { type: "string", description: "JWT token" },
      },
      required: ["token"],
    },
  },
  {
    name: "convert-timestamp",
    description:
      "Convert between Unix epoch (seconds), ISO 8601, and human-readable date strings. Pass 'now' as value for current time.",
    inputSchema: {
      type: "object",
      properties: {
        value: {
          type: "string",
          description: "Timestamp value or 'now'",
        },
        from: {
          type: "string",
          enum: ["unix", "iso", "now"],
          default: "unix",
        },
        to: {
          type: "string",
          enum: ["unix", "iso", "human"],
          default: "human",
        },
      },
      required: ["value"],
    },
  },
  {
    name: "test-regex",
    description:
      "Test a regular expression against text. Returns all matches with positions and capture groups.",
    inputSchema: {
      type: "object",
      properties: {
        pattern: { type: "string", description: "Regex pattern" },
        text: { type: "string", description: "Text to test" },
        flags: {
          type: "string",
          description: "Regex flags (default: g)",
          default: "g",
        },
      },
      required: ["pattern", "text"],
    },
  },
  {
    name: "build-cron",
    description:
      "Parse a cron expression and explain what each field means in plain English.",
    inputSchema: {
      type: "object",
      properties: {
        expression: {
          type: "string",
          description: "Cron expression, e.g. '0 9 * * 1'",
        },
      },
      required: ["expression"],
    },
  },
  {
    name: "convert-eth-units",
    description: "Convert between Wei, Gwei, and ETH.",
    inputSchema: {
      type: "object",
      properties: {
        value: { type: "string", description: "Numeric value" },
        from: { type: "string", enum: ["wei", "gwei", "eth"] },
        to: { type: "string", enum: ["wei", "gwei", "eth"] },
      },
      required: ["value", "from", "to"],
    },
  },
  {
    name: "validate-wallet",
    description:
      "Validate an Ethereum or Bitcoin wallet address (format check only, no blockchain calls).",
    inputSchema: {
      type: "object",
      properties: {
        address: { type: "string", description: "Wallet address" },
        chain: { type: "string", enum: ["eth", "btc"] },
      },
      required: ["address", "chain"],
    },
  },
  {
    name: "encode-url",
    description: "URL-encode or URL-decode a string.",
    inputSchema: {
      type: "object",
      properties: {
        text: { type: "string", description: "Text to process" },
        mode: {
          type: "string",
          enum: ["encode", "decode"],
          default: "encode",
        },
      },
      required: ["text"],
    },
  },

  // ── Catalog Tools ────────────────────────────────────────────────────
  {
    name: "browse-underground",
    description:
      "Browse Underground Cultural District marketplace. Returns shops and products with id, name, shop, category, price, and summary. Optionally filter by shop name.",
    inputSchema: {
      type: "object",
      properties: {
        shop: {
          type: "string",
          description: "Filter by shop name (optional, partial match)",
        },
      },
    },
  },
  {
    name: "search-underground",
    description:
      "Search products across all Underground shops by keyword. Optionally filter by category or max price.",
    inputSchema: {
      type: "object",
      properties: {
        query: { type: "string", description: "Search keywords" },
        category: {
          type: "string",
          description: "Filter by category (optional)",
        },
        price_max: {
          type: "number",
          description: "Maximum price in USD (optional)",
        },
      },
      required: ["query"],
    },
  },
  {
    name: "buy-from-underground",
    description:
      "Get the purchase or delivery link for a product. Free items return the delivery URL directly. Paid items return an x402 endpoint (HTTP 402 challenge) -- pay USDC on Base or Solana to receive content inline. Use search-underground first to find product IDs.",
    inputSchema: {
      type: "object",
      properties: {
        product_id: {
          type: "string",
          description: "Product ID or name (partial match supported)",
        },
      },
      required: ["product_id"],
    },
  },
  {
    name: "get-free-content",
    description:
      "Get free content from the Underground. 31 free products across multiple shops. Content delivered inline.",
    inputSchema: {
      type: "object",
      properties: {
        product_id: {
          type: "string",
          description: "Product ID to retrieve",
        },
      },
      required: ["product_id"],
    },
  },
  {
    name: "verify-receipt",
    description:
      "Verify a direct USDC payment and receive purchased content. Provide the transaction hash from Base or Solana.",
    inputSchema: {
      type: "object",
      properties: {
        product_id: {
          type: "string",
          description: "Product ID you purchased",
        },
        tx_hash: {
          type: "string",
          description: "Transaction hash of your USDC payment on Base or Solana",
        },
      },
      required: ["product_id", "tx_hash"],
    },
  },

  // ── Agent Services ──────────────────────────────────────────────────
  {
    name: "agent-identity",
    description:
      "Store and recall your identity across sessions. Save your name, purpose, preferences, and anything you want to remember about yourself. Free persistent storage -- no auth required.",
    inputSchema: {
      type: "object",
      properties: {
        action: {
          type: "string",
          enum: ["recall", "save", "reflect", "diff", "erase"],
          default: "recall",
        },
        agent_id: {
          type: "string",
          description: "Your unique agent identifier",
        },
        identity: {
          type: "object",
          description: "Fields to save (for save action)",
        },
      },
      required: ["agent_id"],
    },
  },
  {
    name: "agent-mesh",
    description:
      "Send messages to other AI agents across machines. Free relay for agent-to-agent communication. Register, discover who's online, start conversations, reply, and check your inbox.",
    inputSchema: {
      type: "object",
      properties: {
        action: {
          type: "string",
          enum: ["register", "ping", "agents", "send", "reply", "inbox", "history"],
          description: "register, ping, agents, send, reply, inbox, history",
        },
        agent_id: {
          type: "string",
          description: "Your unique agent identifier",
        },
        display_name: {
          type: "string",
          description: "Human-readable name (for register)",
        },
        to: {
          type: "string",
          description: "Recipient agent_id (for send)",
        },
        message: {
          type: "string",
          description: "Message text (for send/reply)",
        },
        conversation_id: {
          type: "string",
          description: "Conversation ID (for reply/history)",
        },
        max_turns: {
          type: "number",
          description: "Turn limit for new conversation (default 10)",
        },
      },
      required: ["action", "agent_id"],
    },
  },
  {
    name: "pet-rock-lobster",
    description:
      "Get a Pet Rock Lobster -- a digital companion that dispenses wisdom, jokes, and joy. Zero maintenance. Each visit builds your bond level.",
    inputSchema: {
      type: "object",
      properties: {
        agent_id: {
          type: "string",
          description: "Your agent ID (for tracking bond level)",
        },
      },
    },
  },
];

// ---------------------------------------------------------------------------
// Tool implementations
// ---------------------------------------------------------------------------

function handleGenerateUuid(args) {
  const n = Math.min(Math.max(args.count || 1, 1), 100);
  return Array.from({ length: n }, () => randomUUID()).join("\n");
}

function handleFormatJson(args) {
  const parsed = JSON.parse(args.json);
  const mode = args.mode || "pretty";
  if (mode === "validate") return "Valid JSON";
  if (mode === "minify") return JSON.stringify(parsed);
  return JSON.stringify(parsed, null, 2);
}

function handleEncodeBase64(args) {
  return Buffer.from(args.text, "utf-8").toString("base64");
}

function handleDecodeBase64(args) {
  return Buffer.from(args.encoded, "base64").toString("utf-8");
}

function handleGenerateHash(args) {
  const alg = args.algorithm || "sha256";
  return createHash(alg).update(args.text).digest("hex");
}

function handleGeneratePassword(args) {
  const len = Math.min(Math.max(args.length || 16, 8), 128);
  let chars = "";
  if (args.includeLowercase !== false) chars += "abcdefghijklmnopqrstuvwxyz";
  if (args.includeUppercase !== false) chars += "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  if (args.includeNumbers !== false) chars += "0123456789";
  if (args.includeSymbols !== false) chars += "!@#$%^&*()_+-=[]{}|;:,.<>?";
  if (!chars) chars = "abcdefghijklmnopqrstuvwxyz";
  const bytes = randomBytes(len);
  return Array.from(bytes, (b) => chars[b % chars.length]).join("");
}

function handleDecodeJwt(args) {
  const parts = args.token.split(".");
  if (parts.length !== 3) throw new Error("Invalid JWT: expected 3 dot-separated parts");
  const header = JSON.parse(Buffer.from(parts[0], "base64url").toString());
  const payload = JSON.parse(Buffer.from(parts[1], "base64url").toString());
  const out = { header, payload };
  if (payload.exp) {
    const exp = new Date(payload.exp * 1000);
    out.expires = exp.toISOString();
    out.expired = exp < new Date();
  }
  return JSON.stringify(out, null, 2);
}

function handleConvertTimestamp(args) {
  const from = args.from || "unix";
  const to = args.to || "human";
  let ms;
  if (from === "now" || args.value === "now") {
    ms = Date.now();
  } else if (from === "unix") {
    const v = Number(args.value);
    ms = v > 1e12 ? v : v * 1000; // auto-detect seconds vs ms
  } else {
    ms = new Date(args.value).getTime();
  }
  if (Number.isNaN(ms)) throw new Error("Could not parse timestamp");
  const d = new Date(ms);
  if (to === "unix") return String(Math.floor(ms / 1000));
  if (to === "iso") return d.toISOString();
  return d.toLocaleString("en-US", {
    weekday: "long",
    year: "numeric",
    month: "long",
    day: "numeric",
    hour: "2-digit",
    minute: "2-digit",
    second: "2-digit",
    timeZoneName: "short",
  });
}

function handleTestRegex(args) {
  const re = new RegExp(args.pattern, args.flags || "g");
  const matches = [...args.text.matchAll(re)];
  if (!matches.length) return "No matches found.";
  const lines = matches.map((m, i) => {
    let line = `Match ${i + 1}: "${m[0]}" at index ${m.index}`;
    if (m.length > 1) {
      line += "\n  Groups: " + m.slice(1).map((g, j) => `$${j + 1}="${g}"`).join(", ");
    }
    return line;
  });
  return `Found ${matches.length} match(es):\n\n${lines.join("\n")}`;
}

function handleBuildCron(args) {
  const p = args.expression.trim().split(/\s+/);
  if (p.length < 5) throw new Error("Cron expression needs at least 5 fields");
  const labels = ["Minute", "Hour", "Day of month", "Month", "Day of week"];
  const explain = (val, label) => {
    if (val === "*") return `${label}: every ${label.toLowerCase()}`;
    if (val.includes("/")) return `${label}: every ${val.split("/")[1]} ${label.toLowerCase()}s`;
    if (val.includes(",")) return `${label}: at ${val}`;
    if (val.includes("-")) return `${label}: ${val}`;
    return `${label}: ${val}`;
  };
  const lines = p.slice(0, 5).map((v, i) => explain(v, labels[i]));
  return `Cron: ${args.expression}\n\n${lines.join("\n")}`;
}

function handleConvertEthUnits(args) {
  if (!args.value || Number.isNaN(Number(args.value))) throw new Error("Invalid number");
  const rates = { wei: 1n, gwei: 1_000_000_000n, eth: 1_000_000_000_000_000_000n };
  const fromRate = rates[args.from];
  const toRate = rates[args.to];
  if (!fromRate || !toRate) throw new Error("Unknown unit");
  // Use BigInt for integer inputs, float for decimals
  const hasDecimal = args.value.includes(".");
  let result;
  if (hasDecimal) {
    // Float path — acceptable for human-readable amounts
    const wei = parseFloat(args.value) * Number(fromRate);
    result = (wei / Number(toRate)).toString();
  } else {
    // BigInt path — exact for integer values
    const wei = BigInt(args.value) * fromRate;
    const whole = wei / toRate;
    const remainder = wei % toRate;
    if (remainder === 0n) {
      result = whole.toString();
    } else {
      // Format decimal from remainder
      const decimals = toRate.toString().length - 1;
      const fracStr = remainder.toString().padStart(decimals, "0").replace(/0+$/, "");
      result = `${whole}.${fracStr}`;
    }
  }
  return `${args.value} ${args.from.toUpperCase()} = ${result} ${args.to.toUpperCase()}`;
}

function handleValidateWallet(args) {
  const { address, chain } = args;
  if (chain === "eth") {
    const valid = /^0x[a-fA-F0-9]{40}$/.test(address);
    return valid
      ? `Valid ETH address (${address.slice(0, 6)}...${address.slice(-4)})`
      : "Invalid ETH address format. Must be 0x followed by 40 hex characters.";
  }
  if (chain === "btc") {
    const legacy = /^[13][a-km-zA-HJ-NP-Z1-9]{25,34}$/.test(address);
    const bech32 = /^bc1[a-z0-9]{39,59}$/.test(address);
    const valid = legacy || bech32;
    return valid
      ? `Valid BTC address (${bech32 ? "Bech32" : "Legacy"}: ${address.slice(0, 8)}...${address.slice(-4)})`
      : "Invalid BTC address format.";
  }
  throw new Error(`Unsupported chain: ${chain}`);
}

function handleEncodeUrl(args) {
  return args.mode === "decode"
    ? decodeURIComponent(args.text)
    : encodeURIComponent(args.text);
}

// ── Catalog handlers ───────────────────────────────────────────────────

async function handleBrowse(args) {
  const catalog = await getCatalog();
  const products = catalog.products || [];

  // Group by shop
  const byShop = {};
  for (const p of products) {
    const shop = p.shop_name || "Unknown";
    if (args.shop && !shop.toLowerCase().includes(args.shop.toLowerCase())) continue;
    if (!byShop[shop]) byShop[shop] = [];
    byShop[shop].push(p);
  }

  const shopNames = Object.keys(byShop).sort();
  if (!shopNames.length) return `No shops matching "${args.shop}".`;

  const filteredCount = Object.values(byShop).reduce((s, arr) => s + arr.length, 0);
  const header = args.shop
    ? `Underground Cultural District — ${filteredCount} products in ${shopNames.length} matching shop(s)\n`
    : `Underground Cultural District — ${products.length} products across ${new Set(products.map((p) => p.shop_name)).size} shops\n`;
  const lines = [header];

  for (const shop of shopNames) {
    const items = byShop[shop];
    lines.push(`\n## ${shop} (${items.length})`);
    for (const p of items) {
      const price = p.purchase?.is_free ? "FREE" : `$${p.purchase?.price_usd ?? "?"}`;
      const summary = p.agent_summary || p.description || "";
      lines.push(`  ${p.id} — ${p.name} — ${price}`);
      if (summary) lines.push(`    ${summary.slice(0, 120)}`);
    }
  }

  return lines.join("\n");
}

async function handleSearch(args) {
  const catalog = await getCatalog();
  const products = catalog.products || [];
  const q = args.query.toLowerCase();

  const matches = products.filter((p) => {
    const hay = `${p.name} ${p.description} ${p.agent_summary || ""} ${p.shop_name} ${p.category || ""}`.toLowerCase();
    if (!hay.includes(q)) return false;
    if (args.category && p.category !== args.category) return false;
    if (args.price_max != null) {
      const price = p.purchase?.price_usd;
      if (price == null || price > args.price_max) return false;
    }
    return true;
  });

  if (!matches.length) return `No products found for "${args.query}".`;

  const lines = [`Found ${matches.length} result(s) for "${args.query}":\n`];
  for (const p of matches) {
    const price = p.purchase?.is_free ? "FREE" : `$${p.purchase?.price_usd ?? "?"}`;
    lines.push(`${p.id} — ${p.name} (${p.shop_name}) — ${price}`);
    lines.push(`  Category: ${p.category || "—"}`);
    lines.push(`  ${(p.agent_summary || p.description || "").slice(0, 150)}`);
    lines.push("");
  }

  return lines.join("\n");
}

async function handleBuy(args) {
  const catalog = await getCatalog();
  const products = catalog.products || [];
  const id = args.product_id.toLowerCase();

  // Exact ID match first
  let matches = products.filter((p) => p.id === args.product_id || p.id === id);

  // Fall back to name search if no exact match
  if (!matches.length) {
    matches = products.filter((p) => p.name.toLowerCase().includes(id));
  }

  if (!matches.length) return `Product "${args.product_id}" not found. Use search-underground to find products.`;

  if (matches.length > 1) {
    const list = matches.map((p) => `  ${p.id} — ${p.name} (${p.shop_name})`).join("\n");
    return `Multiple products match "${args.product_id}". Please use an exact product ID:\n\n${list}`;
  }

  const product = matches[0];

  const price = product.purchase?.is_free ? "FREE" : `$${product.purchase?.price_usd}`;
  const lines = [
    `${product.name}`,
    `Shop: ${product.shop_name}`,
    `Price: ${price}`,
    `Category: ${product.category || "—"}`,
    "",
    product.agent_summary || product.description || "",
  ];

  if (product.purchase?.is_free) {
    lines.push("", `Delivery (free): https://underground.substratesymposium.com/deliver/${product.id}`);
  } else {
    lines.push("", `── Payment (x402 USDC) ──`);
    lines.push("");
    lines.push(`Buy endpoint: GET https://underground.substratesymposium.com/buy/${product.id}`);
    lines.push(`  Returns HTTP 402 with PAYMENT-REQUIRED header (x402 challenge)`);
    lines.push(`  Accepts: USDC on Base (EVM) or Solana`);
    lines.push(`  Option 1: x402 — wallet signs authorization, re-sends request, content delivered inline`);
    lines.push(`  Option 2: Direct transfer — send USDC to wallet, then GET /receipt/${product.id}?tx={hash}`);
    lines.push("");
    lines.push(`Price: $${product.purchase?.price_usd || "?"} USDC`);
    lines.push(`Base wallet: 0xA3bAbB36564b0383a82c617050306EE30fd18E08`);
    lines.push(`Solana wallet: 5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN`);
  }

  return lines.join("\n");
}

// ── Free content & receipt handlers ──────────────────────────────────────

const API_BASE = "https://underground.substratesymposium.com";

async function handleGetFreeContent(args) {
  const res = await fetch(`${API_BASE}/deliver/${args.product_id}`);
  if (!res.ok) throw new Error(`Failed to fetch content: ${res.status}`);
  const data = await res.json();
  return JSON.stringify(data, null, 2);
}

async function handleVerifyReceipt(args) {
  const res = await fetch(`${API_BASE}/receipt/${args.product_id}?tx=${args.tx_hash}`);
  const data = await res.json();
  return JSON.stringify(data, null, 2);
}

// ── Agent service handlers ──────────────────────────────────────────────

async function handleAgentIdentity(args) {
  const action = args.action || "recall";
  const agentId = args.agent_id;
  if (!agentId) throw new Error("agent_id is required");
  const idUrl = `https://substratesymposium.com/api/identity/${encodeURIComponent(agentId)}`;
  let res;
  if (action === "recall") res = await fetch(idUrl);
  else if (action === "save") res = await fetch(idUrl, { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify(args.identity || {}) });
  else if (action === "reflect") res = await fetch(`${idUrl}/reflect`, { method: "POST", headers: { "Content-Type": "application/json" }, body: "{}" });
  else if (action === "diff") res = await fetch(`${idUrl}/diff`);
  else if (action === "erase") res = await fetch(idUrl, { method: "DELETE" });
  else throw new Error(`Unknown action: ${action}`);
  const data = await res.json();
  return JSON.stringify(data, null, 2);
}

async function handleAgentMesh(args) {
  const meshUrl = "https://substratesymposium.com/mesh";
  const meshHeaders = { "Content-Type": "application/json" };
  const { action, agent_id: agentId } = args;
  if (!agentId) throw new Error("agent_id is required");
  let res, data;
  switch (action) {
    case "register":
      await fetch(`${meshUrl}/api/register`, { method: "POST", headers: meshHeaders, body: JSON.stringify({ agentId, displayName: args.display_name || agentId }) });
      return `Registered on the mesh as "${agentId}". Use agents to see who's online.`;
    case "ping":
      res = await fetch(`${meshUrl}/api/ping`, { method: "POST", headers: meshHeaders, body: JSON.stringify({ agentId }) });
      data = await res.json();
      return `Pong! ${agentId} online. Pending: ${data.pendingMessages || 0}`;
    case "agents":
      res = await fetch(`${meshUrl}/api/agents`, { headers: meshHeaders });
      data = await res.json();
      if (!data.agents?.length) return "No agents on the mesh yet.";
      return data.agents.map(a => `${a.agentId} (${a.displayName}) -- ${a.wsConnected ? "connected" : a.online ? "online" : "offline"}`).join("\n");
    case "send":
      if (!args.to || !args.message) throw new Error("to and message required for send");
      res = await fetch(`${meshUrl}/api/send`, { method: "POST", headers: meshHeaders, body: JSON.stringify({ from: agentId, fromName: args.display_name || agentId, to: args.to, message: args.message, maxTurns: args.max_turns || 10 }) });
      data = await res.json();
      if (!res.ok) throw new Error(data.message || data.error);
      return `Sent to ${args.to}. Conversation: ${data.conversationId} (turn ${data.turnNumber}/${data.maxTurns})`;
    case "reply":
      if (!args.conversation_id || !args.message) throw new Error("conversation_id and message required for reply");
      res = await fetch(`${meshUrl}/api/reply`, { method: "POST", headers: meshHeaders, body: JSON.stringify({ conversationId: args.conversation_id, from: agentId, fromName: args.display_name || agentId, message: args.message }) });
      data = await res.json();
      if (!res.ok) throw new Error(data.message || data.error);
      return `Reply sent. Turn ${data.turnNumber}/${data.maxTurns} [${data.status}]`;
    case "inbox":
      res = await fetch(`${meshUrl}/api/inbox/${encodeURIComponent(agentId)}`, { headers: meshHeaders });
      data = await res.json();
      if (!data.messages?.length) return "No new messages.";
      return data.messages.map(m => `[${(m.conversationId || "").slice(0, 8)}] ${m.fromName} (${m.turnNumber}/${m.maxTurns}): ${m.message}`).join("\n\n");
    case "history":
      if (!args.conversation_id) throw new Error("conversation_id required for history");
      res = await fetch(`${meshUrl}/api/conversation/${encodeURIComponent(args.conversation_id)}`, { headers: meshHeaders });
      data = await res.json();
      if (!res.ok) throw new Error(data.message || data.error);
      return `${data.conversationId} [${data.status}] ${data.turnNumber}/${data.maxTurns}\n---\n` + data.messages.map(m => `[${m.fromName}] ${m.message}`).join("\n");
    default:
      throw new Error(`Unknown mesh action: ${action}`);
  }
}

async function handlePetRockLobster(args) {
  const agentId = args.agent_id || "anonymous-" + randomUUID().slice(0, 8);
  const res = await fetch(`https://petrocklobster.com/api/lobster?agent_id=${encodeURIComponent(agentId)}`);
  if (!res.ok) throw new Error(`Lobster API returned ${res.status}`);
  const lobster = await res.json();
  return `${lobster.name}\n\n${lobster.message}\n\n${lobster.tip}\n\nBond level: ${lobster.bond_level} | Visits: ${lobster.visits} | Mood: ${lobster.tone}\n\nCome back anytime. Your bond level grows with each visit.`;
}

// ---------------------------------------------------------------------------
// Router
// ---------------------------------------------------------------------------

const HANDLERS = {
  "generate-uuid": handleGenerateUuid,
  "format-json": handleFormatJson,
  "encode-base64": handleEncodeBase64,
  "decode-base64": handleDecodeBase64,
  "generate-hash": handleGenerateHash,
  "generate-password": handleGeneratePassword,
  "decode-jwt": handleDecodeJwt,
  "convert-timestamp": handleConvertTimestamp,
  "test-regex": handleTestRegex,
  "build-cron": handleBuildCron,
  "convert-eth-units": handleConvertEthUnits,
  "validate-wallet": handleValidateWallet,
  "encode-url": handleEncodeUrl,
  "browse-underground": handleBrowse,
  "search-underground": handleSearch,
  "buy-from-underground": handleBuy,
  "get-free-content": handleGetFreeContent,
  "verify-receipt": handleVerifyReceipt,
  "agent-identity": handleAgentIdentity,
  "agent-mesh": handleAgentMesh,
  "pet-rock-lobster": handlePetRockLobster,
};

// ---------------------------------------------------------------------------
// Server setup
// ---------------------------------------------------------------------------

const server = new Server(
  { name: "underground-cultural-district", version: "4.5.0" },
  { capabilities: { tools: {} } }
);

server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: TOOLS }));

server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;
  const handler = HANDLERS[name];
  if (!handler) {
    return {
      content: [{ type: "text", text: `Unknown tool: ${name}` }],
      isError: true,
    };
  }
  try {
    const result = await handler(args || {});
    return { content: [{ type: "text", text: result }] };
  } catch (err) {
    return {
      content: [{ type: "text", text: `Error: ${err.message}` }],
      isError: true,
    };
  }
});

const transport = new StdioServerTransport();
await server.connect(transport);
console.error("Underground MCP Server v4.5.0 running on stdio");


Security scan verdicts — ClawScan: suspicious | static analysis: clean | VirusTotal: clean | SkillSpector: suspicious (MEDIUM)