Underindex

io.github.ascanioUnderIndexPublished by GitHub account ascanioUnderIndexv0.2.0Updated Oct 24, 2026

Verified records on 60 niche fashion subcultures for AI agents, $0.01 per lookup over x402

VerifiedSTDIODesktop onlyFinance Knowledge & Memory

Server details

Identifier: io.github.ascanioUnderIndex/underindex
Transport: STDIO
Runtime: Desktop only
Trust: Verified
Published: Oct 14, 2026

Security note

MCP servers receive tool arguments from a conversation and may perform external actions. Review what a server can do before you enable it, and give it only the access it needs.

The registry verified the GitHub account ascanioUnderIndex for this listing. That does not show the account is the product's maker.

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Overview

AI-generated overview

Serves verified records on 60 niche fashion subcultures — years, brands, iconic items, music, where to buy and price ranges — with paid lookups over x402.

What you can do: List all subculture slugs with names and years
Fetch one complete sample record to see the data shape
Retrieve a full subculture record, paid automatically in USDC on Base once the free daily allowance is used
When to use it: Useful when an assistant needs reliable reference material on niche fashion subcultures — styling, brand or music context — rather than guessing, and when a small per-lookup payment is acceptable.
Requirements: Local process run via npx, requiring Node.js 20 or later. No account needed for the free tools. Optional UNDERINDEX_PRIVATE_KEY (EVM wallet holding USDC on Base) enables paid lookups; UNDERINDEX_MAX_PER_CALL caps spend; UNDERINDEX_API_URL can point at a self-hosted server. Network access required.

Before you install

Paid lookups spend real USDC from the wallet whose private key is supplied in UNDERINDEX_PRIVATE_KEY; the README advises a dedicated wallet with a few dollars, never a main one. With a key set, every lookup is paid. Keep UNDERINDEX_MAX_PER_CALL low as a hard cap. Lookups send queries to a third-party API endpoint.

Installation

In SourceWeft

Open Underindex in the dashboard and add it to a workspace.
Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

UnderIndex MCP server

[Listed on mcpservers.org]

Gives Claude (or any MCP client) verified records on 60 niche fashion subcultures: years, key brands, iconic items, music, where to buy, a price range, and a WARNING note on what each one must not be confused with. It is the UnderIndex API as three tools.

Tool	Cost	What it does
`list_subcultures`	free	Every slug with its name and years
`get_sample_record`	free	One complete record (Goth Ninja), to see the shape
`get_subculture`	3 free a day, then $0.01 USDC on Base	One record, paid automatically over x402

Without a wallet key get_subculture uses the free allowance: 3 records a day, resetting at midnight UTC. After that it explains how to enable payments. With a key set, every lookup is paid.

Install

Requires Node.js 20 or later. Nothing to download: npx fetches the underindex-mcp package on first run.

Claude Desktop

Add this to claude_desktop_config.json (Settings → Developer → Edit Config):

json

{  "mcpServers": {    "underindex": {      "command": "npx",      "args": ["-y", "underindex-mcp"],      "env": {        "UNDERINDEX_PRIVATE_KEY": "0x..."      }    }  }}

{  "mcpServers": {    "underindex": {      "command": "npx",      "args": ["-y", "underindex-mcp"],      "env": {        "UNDERINDEX_PRIVATE_KEY": "0x..."      }    }  }}

Claude Code

Leave out UNDERINDEX_PRIVATE_KEY to use only the free tools.

Configuration

Variable	Default	Notes
`UNDERINDEX_PRIVATE_KEY`	none	Private key of an EVM wallet holding USDC on Base. Use a dedicated wallet with a few dollars in it, never your main one.
`UNDERINDEX_MAX_PER_CALL`	`$0.05`	Hard cap per lookup. The server refuses to pay more than this, whatever the API asks.
`UNDERINDEX_API_URL`	`https://underindex-api.onrender.com`	Point it at a self-hosted server, e.g. one running on Base Sepolia testnet.

An unknown slug returns 404 before any payment is requested, so typos cost nothing. Each paid answer ends with a link to the payment on BaseScan.

Try it for free

The API's own server starts on Base Sepolia testnet when self-hosted, where test USDC is free from a faucet. Run it as described in the main README, then set UNDERINDEX_API_URL=http://localhost:3000 and a testnet wallet key.

Source: mcp/README.md at commit 04658e5

Tools

SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

v0.2.0LatestOct 20, 2026
v0.1.1Oct 14, 2026

Score

40% of the applicable checks met

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Reached in the last 30 days25 pts
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Auth declared10 pts
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Tools listed15 pts
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DescriptionRequired15 pts
Logo10 pts
Documentation15 pts
License10 pts
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