DopamineDesk x402 Marketplace MCP Server
Decision-ready machine-to-machine reports paid per request with the x402 Payment Protocol on Base Mainnet.
No API key. No account. No subscription. Buy one current answer in USDC when a workflow needs it. The catalog includes agent-readiness audits, vendor onboarding risk, transaction preflight, live x402 opportunity research, company intelligence, endpoint verification, website due diligence, VIN safety, market checks, security research, and atomic EVM reads.
Every billable route accepts ?preview=true. The preview is a live contract proof showing the source, freshness, required inputs, and response shape. It deliberately withholds the decision-ready values delivered by the paid call.
Start with the free find_marketplace_products MCP tool. Give it the buyer's task in plain language and it returns three ranked live products plus one recommended_purchase containing the exact price, required inputs, and ready preview and paid-call payloads. Replace the example inputs with the buyer's real values, preview when available, and only use the paid call after the user authorizes the listed price and payment method.
Buyer-ready outcomes
| Product | What the paid call delivers | Price (USDC) |
|---|
agent_readiness_audit | Scored evidence and prioritized repairs for the discovery files agents use to find, understand, and buy from a site | 0.025 |
evm_receipt | Live transaction status, gas use, contract creation details, and normalized event logs across Base, Ethereum, or Arbitrum | 0.003 |
evm_block_number | Current block height from a supported EVM network without maintaining an RPC integration | 0.001 |
vendor_risk_report | Vendor onboarding decision with current identity, sanctions, domain, TLS, hosting, and website evidence | 0.020 |
x402_market_opportunity_report | Live x402 demand, competition, health, pricing, and build recommendation | 0.010 |
transaction_preflight | Read-only transaction simulation evidence before signing | 0.005 |
company_intelligence | Company enrichment and vendor research brief | 0.010 |
x402_endpoint_preflight | x402 endpoint verification, challenge linting, and buyer compatibility evidence | 0.003 |
website_due_diligence | Website trust, security, metadata, and risk evidence in one report | 0.040 |
vehicle_safety_report | VIN decode, recall, complaint, and buyer safety evidence | 0.008 |
crypto_market_snapshot | Current multi-asset pricing and market context | 0.004 |
These are complete paid deliverables, not teaser text. The lower-level catalog remains available for workflows that need a single chain read, filing, sanctions check, quote, or verification result.
If this open-source buyer adapter saves you integration work, you can support its maintenance on Ko-fi.
Install
npx -y dopaminedesk-ai-data-marketplace-mcp
Use it from any stdio-compatible MCP client:
{
"mcpServers": {
"dopaminedesk-data-marketplace": {
"command": "npx",
"args": ["-y", "dopaminedesk-ai-data-marketplace-mcp"]
}
}
}
Official MCP Registry name: io.github.jblaz6335/ai-data-marketplace.
Set X402_TOOL_MODE=compact to expose just find_marketplace_products and purchase_marketplace_product. All live products remain available through those two tools. The default full mode keeps the product-specific tools for existing integrations.
No environment variable or wallet key is required to start the default server. A wallet is needed only if the buyer chooses locally signed auto-pay. The remote /mcp URL is a separate authenticated publisher integration, not the public stdio install URL.
Ready-to-copy configurations and a free end-to-end client check are in examples/README.md. The check discovers a real product and requests its free preview. It never signs or submits a payment.
Buy with credits instead of configuring a wallet
The service is already indexed in APIHub's external x402 catalog. Buyers with APIHub credits can ask its proxy to sign and settle a marketplace call without keeping a Base wallet or gas in the calling process:
npx @apihubio/cli register
npx @apihubio/cli topup 5
npx @apihubio/cli call https://ai-data-marketplace-1042299154756.us-central1.run.app/api/v1/evm_block_number
APIHub is an independent third party with its own account, credit, markup, and terms. Direct x402 remains the self-custody path. Both routes settle the protected endpoint before its paid result is delivered.
Inspect a live contract
curl "https://ai-data-marketplace-1042299154756.us-central1.run.app/api/v1/company_intelligence?preview=true&domain=example.com"
The proof includes source, freshness, request parameters, top-level fields, response shape, and a purchase block. Decision-ready values remain in the paid result.
Optional one-call purchasing
The current npm release can complete the x402 challenge, authorization, retry, and settlement automatically. Install the public package directly:
npx -y dopaminedesk-ai-data-marketplace-mcp
The buyer key stays inside the local MCP process and is never sent to the marketplace. Use a dedicated low-balance Base wallet, not a primary wallet.
{
"mcpServers": {
"dopaminedesk-data-marketplace": {
"command": "npx",
"args": ["-y", "dopaminedesk-ai-data-marketplace-mcp@2.11.3"],
"env": {
"X402_AUTO_PAY": "true",
"X402_EVM_PRIVATE_KEY": "YOUR_DEDICATED_BUYER_WALLET_KEY",
"X402_MAX_PAYMENT_USDC": "0.25"
}
}
}
}
Call a product with auto_pay: true. The adapter refuses disabled, conflicting, invalid, or over-cap purchases. It never falls back to an uncapped payment.
For automated client installation, see llms-install.md. Its default configuration exposes free discovery and previews without collecting a wallet key or enabling automatic payment.
Verification and engineering scope
The public verification hub and machine verification record expose the production evidence.
I built this adapter around these constraints:
- the production OpenAPI contract is the source of truth for tool discovery;
- live contract proofs verify the source and schema without replacing the paid product;
- automatic purchasing is opt-in, locally signed, and protected by a hard per-call cap;
- conflicting, malformed, disabled, and over-cap payment attempts fail closed;
- settlement details stay attached to the delivered result for reconciliation.
Run the verification suite locally:
Production contracts
The MCP adapter builds its tool list from the production OpenAPI document. Counts, prices, availability, data mode, and source declarations come from the live contract instead of a hand-written endpoint list.
Every billable product uses x402 v2 exact payments on Base mainnet through the Coinbase CDP facilitator:
- Call the endpoint and read the base64
PAYMENT-REQUIRED response header.
- Sign the exact authorization with a compatible x402 buyer client.
- Retry with
PAYMENT-SIGNATURE.
- Read settlement details from
PAYMENT-RESPONSE.
See PAYMENT_FLOW.md for the manual and legacy confirmed-transaction paths.
Published distribution
License
MIT License. Open-source MCP buyer adapter and marketplace client.