LocationLists — Agent Wallet

Give Claude a wallet, and it can buy business location data on its own. No card, no account, no checkout page.

Claude cannot sign an on-chain payment — it holds no keys, and it never will. So the wallet lives in a tool Claude calls. Claude decides what to buy; this extension holds the money and signs for it. That is not a workaround; it is the shape agent payments actually take.

What happens

You ask Claude a question it needs data to answer. Claude finds the right list with find_location_lists, reads its columns with get_list_details, sizes and prices the answer with count_matching_records (all free), then calls get_matching_records. Filters reach every column a list carries — revenue, employees, category, dealer tier — not just geography, and the filter arguments are read from locationlists.com at startup, so new ones arrive without reinstalling.

The extension asks locationlists.com for the records, gets back an x402 payment demand with a price, signs a USDC payment on Base, retries with the payment attached, and hands Claude the rows. By default this speaks the x402 MCP transport (the demand is a tool result, the payment rides in _meta["x402/payment"]); a seller that answers with HTTP 402 is paid through headers instead, and via: "http" buys through the plain HTTP endpoint POST /api/x402/query. Same rows, same price, same limits. The whole thing takes a few seconds and settles on a public blockchain you can check afterwards.

Pricing is per row, derived from each dataset — a slice of a large file costs cents. When the user wants most or all of a list, buy_complete_list buys the whole file at its list price and returns a permanent CSV download link. Datasets under 5,000 records are only sold that way.

Paid tools are read from the seller at startup too: if locationlists.com adds a new paid tool, it appears here under its own name, spending from the per-row limits. Free seller tools pass straight through the same way — request_a_new_list when the list you need does not exist yet, send_feedback, get_sample — with no wallet involved.

Related MCP server: valorem-mev-mcp

Install

1. Download locationlists-buyer.mcpb from Releases.

2. Double-click it. Claude Desktop installs it and asks for four things:

   • Wallet private key — stored in your OS keychain, never in a config file

   • Maximum per purchase (default $1.00) — row purchases

   • Maximum per session (default $5.00) — row purchases

   • Maximum on complete lists per session (default $100.00) — whole-file purchases; 0 turns them off

3. Restart Claude Desktop.

Funding the wallet

Use a dedicated wallet holding only what you are willing to let an AI spend. Not your main one.

You need USDC on Base. From Coinbase: Send → USDC → paste the wallet address → Network: Base → confirm. Picking Ethereum, Arbitrum, Polygon or Optimism instead will accept the address happily and put the money somewhere this cannot spend it.

You do not need ETH. x402 uses gasless EIP-3009 transfers — the facilitator broadcasts the transaction and pays the gas.

$5 is plenty to try it.

Spending limits are not optional

An LLM with a wallet will, sooner or later, call a paid tool in a loop. Three checks run before anything is signed, and a refusal costs nothing:

• per-call cap (row purchases)

• per-session running total (row purchases), held in memory so a restart is a deliberate act

• a separate per-session budget for complete lists, so a $99 file never needs a $99 per-call cap

• on-chain balance check

Ask Claude what's in your wallet? at any point and it will tell you the balance, the session spend, and the limits.

Try it

I sell backup generator installation in Colorado. Find me the Generac dealers there so I know who I'm competing against.

Claude will search the catalog, see the rows cost money, buy the ones it needs, and answer with real dealers — names, addresses, phone numbers.

Which nonprofits in Richmond, Virginia have more than $2M in revenue?

Claude counts first (249, plus 2,114 with no revenue on file), sees the three pages cost under a dollar, and buys them largest first. The tool response names the amount paid and both wallet addresses, so you can verify the transaction on Basescan.

Configuration

Everything is set through Claude Desktop's UI at install time. For other MCP clients, the server reads:

Run from source

git clone https://github.com/kylehawke-stack/x402-buyer-mcp
cd x402-buyer-mcp && npm install
X402_BUYER_KEY=0x... node server.mjs

Then point any MCP client at it over stdio.

One thing worth being precise about

Claude did not pay for anything. Claude decided to buy, and a tool it was given signed the payment. The decision is the novel part; the signature is ordinary software. Anyone describing this should say so.

Licence

MIT