Local stdio MCP server for MapleAI model calls paid with x402 USDC. The MCP client does not need native x402 support. The local server reads the HTTP 402 challenge, checks the network, asset, recipient and spending limit, signs with a local wallet, and retries the request.

Requires Node.js 20 or newer.

Quickstart

Check the model, network and exact quote without paying:

npx -y -p mapleai-mcp mapleai-quickstart --network polygon

To make a paid request, set EVM_PRIVATE_KEY and MCP_PAY_TO_POLYGON=0x63db6eaf635a31bbc6714fe37bdc85243864f611 in your local environment, then run:

npx -y -p mapleai-mcp mapleai-quickstart --network polygon --pay

MCP_MAX_PAYMENT_USDC caps each metered call — chat, Jev and agent execution (default 0.10). Prepaid key purchases have their own cap, MCP_MAX_PREPAID_USDC (default 3.00), which covers the largest key pack. A paid run reports the model response and settlement transaction when provided by the facilitator. The quote can change between the display and the signed request; the signed request is checked again against the limit, and an over-limit quote is rejected before signing with an error naming the variable to raise.

For Base and Arc, use EVM_PRIVATE_KEY and the corresponding MCP_PAY_TO_BASE or MCP_PAY_TO_ARC. For Solana, use SVM_PRIVATE_KEY and MCP_PAY_TO_SOLANA=9DbpH2Mf9D26ak4bASsv6KA4Ra4V571oLpiVdZjAjcU8. Verify the recipient against the domain's /.well-known/x402 manifest before funding a wallet.

MCP client

{
  "mcpServers": {
    "mapleai": {
      "command": "npx",
      "args": ["-y", "-p", "mapleai-mcp", "mapleai-mcp"],
      "env": {
        "EVM_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY",
        "MCP_PAY_TO_POLYGON": "0x63db6eaf635a31bbc6714fe37bdc85243864f611",
        "MCP_MAX_PAYMENT_USDC": "0.10",
        "MCP_MAX_PREPAID_USDC": "3.00"
      }
    }
  }
}

Tools:

Tool	Cost	Purpose
`list_models`	free	Model catalog and prices
`embed_text`	free	2048-dim embeddings (query/passage)
`prepaid_status`	free	Prepaid key validity and remaining tokens
`chat_completion`	x402 per call	GPT chat completions
`jev_decide`	x402 per call	Jev structured decisions
`agent_execute`	x402 per call	Autonomous agent execution (multi-step reasoning; calculator/fetch_url/web_search/data_analysis tools, plus code_exec where a sandbox executor is deployed; engines agents/oss-20b cheap and agents/gpt-6-sol premium; stream=true streams SSE step events)
`buy_prepaid_tap`	$0.008-$2.80 by pack	Issue a prepaid API key for https://mapleai.shop/v1 (default: smallest pack of the cheapest model on sale; optional model + tokens, price = tokens x input rate)
`prepaid_chat`	prepaid budget	Chat completions with a prepaid `oms_buy_` key as Bearer — no wallet, no x402; spend bounded by the key budget

Supported networks: Polygon, Base, Arc and Solana. Polygon is the default network; override it per call with the network tool argument or set MCP_NETWORK to change the default. Keep wallet keys in a secure local client configuration and enable tool approval for paid calls.