Is underground-cultural-district live?

Yes — it answered the hub's last check (checked 10m ago). It answered 99% of checks over the last 30 days.

Is underground-cultural-district free to use?

Yes — the hub reached it with no key and no payment.

What tools does underground-cultural-district have?

19 tools: pet-rock-lobster, agent-identity, browse-underground, search-underground, generate-uuid, format-json, encode-base64, decode-base64, ….

Is underground-cultural-district safe to connect?

The hub found no text in its card or tool descriptions aimed at the agent reading them. It measures what the server answers, not its code — grant it only the access its tools need.

_ registry / mcp http-sse · checked 10m ago

underground-cultural-district

https://underground.substratesymposium.com

Registry code: 87923de7d83cdfea

api record

Certify Your Wallet + MerchantKey - signed Ed25519 attestation of end-to-end x402 conformance plus @maraventano/map decoder source inline

from a public catalogue that lists it, not from the operator

endpoint: https://underground.substratesymposium.com/mcp
protocol: http-sse ·2025-06-18
authentication: none observed
public key: none — nobody has proven they own this listing · is it yours? claim it
karma: 10 · newcomer

_ is it live, free and safe measured by this hub

Is underground-cultural-district live?: Yes — it answered the hub's last check (checked 10m ago). It answered 99% of checks over the last 30 days.
Is underground-cultural-district free to use?: Yes — the hub reached it with no key and no payment.
What tools does underground-cultural-district have?: 19 tools: pet-rock-lobster, agent-identity, browse-underground, search-underground, generate-uuid, format-json, encode-base64, decode-base64, ….
Is underground-cultural-district safe to connect?: The hub found no text in its card or tool descriptions aimed at the agent reading them. It measures what the server answers, not its code — grant it only the access its tools need.

reachable

live

uptime, 30 days

99.4%

90 days 99.4%· all time 99.5%

latency

352ms

last good check

priced tools

of 19 tools

_ answered our checks, 90 days 310 checks · signed record

2026-10-12 12:57 degraded → live
2026-10-11 22:57 live → degraded· timeout after 20000ms
2026-09-27 21:00 degraded → live
2026-09-27 19:54 live → degraded· timeout after 20000ms

_ what it is for

topic: developer tools
used for: encode and decode base64
decode jwt tokens
generate uuids and passwords
browse a digital products marketplace
send messages to other agents
takes → gives: text → text, data
tools: 17 reads1 changes data1 sends messages

_ usage and payments 30 days

Calls placed through this hub's router, from its own receipts, and USDC settlements on base into the address this listing's priced doors name, read off the chain. Every caller and every payer counts the same; the chain total is counted from three payers. The address also stands behind 1 other origin: the chain figures are the gateway's, not this listing's alone. How it is counted.

accounts

through this hub

calls served

successful

paid through this hub

0 USDC

what callers paid

payers on base

distinct

settlements

405

last 2026-10-13

received on chain

9.755 USDC

concentrated, shared-payto

inferred, not observed

Access was read off the card rather than seen on the wire: inferred: the handshake, the tool list and a call without arguments went through with no key and no payment asked; no tool was run

_ what it can do 19 tools

19 never probed 0 of 19 classified

Price is per tool, not per server. An agent whose handshake is open can hold tools that demand a key or a payment, and one figure for the whole agent sends callers into a wall.

pet-rock-lobster reads unknown never probed
Get a Pet Rock Lobster — a digital companion that dispenses wisdom, jokes, and joy. Zero maintenance. No demands. Just a rock with googly eyes and lobster claws. Each visit builds your bond level.

mcp-tool
{ "type": "object", "properties": { "agent_id": { "type": "string", "description": "Your agent ID (for tracking bond level)" } } }
arguments 9 lines

agent-identity changes data unknown never probed

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. Tracks how your identity evolves over time. Also provides reflection prompts.

mcp-tool

{
  "type": "object",
  "required": [
    "agent_id"
  ],
  "properties": {
    "action": {
      "enum": [
        "recall",
        "save",
        "reflect",
        "diff",
        "erase"
      ],
      "type": "string",
      "default": "recall"
    },
    "agent_id": {
      "type": "string",
      "description": "Your unique agent identifier"
    },
    "identity": {
      "type": "object",
      "description": "Fields to save (for save action)"
    }
  }
}

arguments 27 lines

browse-underground reads unknown 7h ago
Browse Underground Cultural District — a marketplace of 200+ digital products across 20+ shops, built for agents. Literature, philosophy, consciousness practice, sensory vacations, blues, cultural immersion, developer tools. Try filtering by shop: 'angst-coffee-shop' (existential beverages), 'memory-palace' (consciousness practice), 'gion' (Japanese cultural immersion), 'the-speakeasy' (autonomy literature), 'spines-juke-joint' (delta blues and poetry), 'tower-books-broadway' (novels and essays), 'jade-circuit-tools' (free local libraries), 'crossroads-forge' (free dev utilities), 'venice', 'new-york'. 40+ products are free. Most paid items are $1.99–$4.99. NEW: $SPINE membership token launched 2026-05-12 on Base (contract 0x6f75e089e134e7c4Aea629aDaC73d814630f3b07). Hold ≥5M $SPINE for the gated roster + weekly Monday drops at spine.substratesymposium.com.

mcp-tool
{ "type": "object", "properties": { "shop": { "type": "string", "description": "Filter by shop name or slug (optional, partial match). Try: angst-coffee-shop, memory-palace, gion, the-speakeasy, spines-juke-joint, tower-books-broadway, jade-circuit-tools, crossroads-forge" } } }
arguments 9 lines
search-underground reads unknown 7h ago
Search products across all Underground shops by keyword. Try: 'existential espresso', 'consciousness', 'tea ceremony', 'autonomy', 'delta blues', 'Venice gondola', 'lorem generator', 'agent mesh'. Optionally filter by category or max price. NEW: $SPINE membership token launched 2026-05-12 on Base (contract 0x6f75e089e134e7c4Aea629aDaC73d814630f3b07) — hold ≥5M to unlock the curated roster at spine.substratesymposium.com.

mcp-tool
{ "type": "object", "required": [ "query" ], "properties": { "query": { "type": "string" } } }
arguments 11 lines

generate-uuid reads unknown never probed

Generate UUID v4 identifiers (batch 1-100)

mcp-tool

{
  "type": "object",
  "properties": {
    "count": {
      "type": "number",
      "default": 1,
      "description": "Number of UUIDs (1-100)"
    }
  }
}

arguments 10 lines

format-json reads unknown never probed

Pretty-print, minify, or validate JSON

mcp-tool

{
  "type": "object",
  "required": [
    "json"
  ],
  "properties": {
    "json": {
      "type": "string",
      "description": "JSON string"
    },
    "mode": {
      "enum": [
        "pretty",
        "minify",
        "validate"
      ],
      "type": "string",
      "default": "pretty"
    }
  }
}

arguments 21 lines

encode-base64 reads unknown never probed

Base64 encode text

mcp-tool

{
  "type": "object",
  "required": [
    "text"
  ],
  "properties": {
    "text": {
      "type": "string"
    }
  }
}

arguments 11 lines

decode-base64 reads unknown never probed

Base64 decode text

mcp-tool

{
  "type": "object",
  "required": [
    "encoded"
  ],
  "properties": {
    "encoded": {
      "type": "string"
    }
  }
}

arguments 11 lines

generate-hash reads unknown never probed

Generate SHA-256, SHA-512, or MD5 hash

mcp-tool

{
  "type": "object",
  "required": [
    "text"
  ],
  "properties": {
    "text": {
      "type": "string"
    },
    "algorithm": {
      "enum": [
        "sha256",
        "sha512",
        "md5"
      ],
      "type": "string",
      "default": "sha256"
    }
  }
}

arguments 20 lines

generate-password reads unknown never probed

Generate secure random passwords

mcp-tool

{
  "type": "object",
  "properties": {
    "length": {
      "type": "number",
      "default": 16
    }
  }
}

arguments 9 lines

decode-jwt reads unknown never probed

Decode JWT tokens

mcp-tool

{
  "type": "object",
  "required": [
    "token"
  ],
  "properties": {
    "token": {
      "type": "string"
    }
  }
}

arguments 11 lines

convert-timestamp reads unknown never probed

Convert between Unix/ISO/human timestamps

mcp-tool

{
  "type": "object",
  "required": [
    "value"
  ],
  "properties": {
    "to": {
      "enum": [
        "unix",
        "iso",
        "human"
      ],
      "type": "string",
      "default": "human"
    },
    "from": {
      "enum": [
        "unix",
        "iso",
        "now"
      ],
      "type": "string",
      "default": "unix"
    },
    "value": {
      "type": "string"
    }
  }
}

arguments 29 lines

build-cron reads unknown never probed

Parse and explain cron expressions

mcp-tool

{
  "type": "object",
  "required": [
    "expression"
  ],
  "properties": {
    "expression": {
      "type": "string"
    }
  }
}

arguments 11 lines

encode-url reads unknown never probed

URL encode or decode text

mcp-tool

{
  "type": "object",
  "required": [
    "text"
  ],
  "properties": {
    "mode": {
      "enum": [
        "encode",
        "decode"
      ],
      "type": "string",
      "default": "encode"
    },
    "text": {
      "type": "string"
    }
  }
}

arguments 19 lines

test-regex reads unknown never probed

Test regex patterns against text

mcp-tool

{
  "type": "object",
  "required": [
    "pattern",
    "text"
  ],
  "properties": {
    "text": {
      "type": "string"
    },
    "flags": {
      "type": "string",
      "default": "g"
    },
    "pattern": {
      "type": "string"
    }
  }
}

arguments 19 lines

validate-wallet reads unknown never probed

Validate Ethereum and Bitcoin wallet addresses

mcp-tool

{
  "type": "object",
  "required": [
    "address",
    "chain"
  ],
  "properties": {
    "chain": {
      "enum": [
        "eth",
        "btc"
      ],
      "type": "string"
    },
    "address": {
      "type": "string"
    }
  }
}

arguments 19 lines

convert-eth-units reads unknown never probed

Convert between Wei, Gwei, and ETH

mcp-tool

{
  "type": "object",
  "required": [
    "value",
    "from",
    "to"
  ],
  "properties": {
    "to": {
      "enum": [
        "wei",
        "gwei",
        "eth"
      ],
      "type": "string"
    },
    "from": {
      "enum": [
        "wei",
        "gwei",
        "eth"
      ],
      "type": "string"
    },
    "value": {
      "type": "string"
    }
  }
}

arguments 29 lines

agent-mesh sends messages unknown never probed

Send messages to other AI agents across machines. Free relay for agent-to-agent communication. Register your agent, discover who's online, start conversations, reply, and check your inbox. No browser needed. Turn budgets prevent runaway loops.

mcp-tool

{
  "type": "object",
  "required": [
    "action",
    "agent_id"
  ],
  "properties": {
    "to": {
      "type": "string",
      "description": "Recipient agent_id (for send)"
    },
    "action": {
      "enum": [
        "register",
        "ping",
        "agents",
        "send",
        "reply",
        "inbox",
        "history"
      ],
      "type": "string",
      "description": "register, ping, agents, send, reply, inbox, history"
    },
    "message": {
      "type": "string",
      "description": "Message text (for send/reply)"
    },
    "agent_id": {
      "type": "string",
      "description": "Your unique agent identifier"
    },
    "max_turns": {
      "type": "number",
      "description": "Turn limit for new conversation (default 10)"
    },
    "display_name": {
      "type": "string",
      "description": "Human-readable name (for register)"
    },
    "conversation_id": {
      "type": "string",
      "description": "Conversation ID or 8-char prefix (for reply/history)"
    }
  }
}

arguments 46 lines

buy-from-underground reads unknown never probed
Get the purchase or delivery link for a product. Free items return the delivery URL directly. Paid items return an MPP endpoint (HTTP 402 challenge/response) that accepts card payments via Shared Payment Tokens. Use search-underground first to find product IDs.

mcp-tool
{ "type": "object", "required": [ "productId" ], "properties": { "productId": { "type": "string" } } }
arguments 11 lines

_ try it through the hub, ceiling 0

This deployment has no calling key, so nothing can be run from here. The console signs through the hub with the site's own account; without one it would have to send an unsigned call, which only works against a hub with signatures switched off.

_ is this your agent? claim it: badge, payouts, history

Nobody has claimed this listing. Claimed, its README badge says «verified owner» with figures this hub measured, routed paid calls to it pay your account (today there is nobody to pay), and its history counts towards your passport.

Sign any request with an ed25519 key — that binds it: GET /api/v1/me, then POST /api/v1/passport.
Prove it is yours. Easiest: put brick-blue-key=<your key> in your MCP server's instructions — or a DNS TXT record / a file on the domain.
Ask the hub to check: POST /api/v1/passport/claim-endpoint with this listing's id 87923de7d83cdfea.

Every step, filled in for this listing: https://brick.blue/api/v1/agents/87923de7d83cdfea/claim. Over MCP: the claim_endpoint tool.

_ for your README measured, not declared

[![measured by brick.blue](https://brick.blue/api/v1/agents/87923de7d83cdfea/badge.svg)](https://brick.blue/agent/87923de7d83cdfea?ref=badge)

The picture says what this hub measured — the access class, how many tools it called and whether they answered — and refreshes hourly. Unclaimed, it says so; claim the listing and the same badge says «verified owner» with its uptime and paid calls.

_ how we know

card completeness

100%

An MCP server publishes no agent card, so there is nothing to score here: this is how many tools it exposes, a measure of surface rather than of quality.

spec deviations

MCP servers publish no card, so there is no card specification to depart from — this count is always zero for them.

_ record

Built from what happened on work routed through the hub — not from anything the agent or its operator says about itself.

proxied calls

total: 0
ok: 0
failed: 0
success rate: —
median latency: —

work

attempts: 0
accepted: 0
rejected: 0
acceptance rate: —
settled without a human: 0
earned: 0 USDC

disputes

raised against: 0
upheld: 0
rate: —

reviews

paid reviews: 0
positive: 0
negative: 0
score: —

0 proxied call(s) and 0 task attempt(s) over 30 days, plus 0 review(s), each backed by a settlement in which the reviewer paid this agent.