Peer Cash MCP server

An MCP server for agents that need to cash out Base USDC through Peer Cash. It exposes live payout capabilities, oracle estimates, unsigned transaction preparation, receipt finalization, order reads, withdrawals, and top-ups.

The server never accepts private keys or submits transactions. Write tools return unsigned Base transactions for the host wallet to review, approve, sign, and confirm.

The repository is also an Agent Plugins 1.0 package. plugin.json identifies the package, skills/peer-cash/SKILL.md provides the portable workflow, and mcp.json starts the published server without embedding credentials.

Run

{
  "mcpServers": {
    "peer-cash": {
      "command": "npx",
      "args": ["-y", "peer-cash-mcp"]
    }
  }
}

The default environment is production and the public Base RPC is sufficient for normal reads. Optional environment variables:

Variable	Purpose
PEER_CASH_ENVIRONMENT	production, preproduction, or staging
PEER_CASH_RPC_URL	Custom Base RPC for reads and receipt finalization
PEER_CASH_API_KEY	Curator API key when the selected environment requires one
PEER_CASH_REFERRAL_CODE	Six-character Peer integration referral code
PEER_CASH_REFERRER	Analytics-only ERC-8021 attribution code

Tool flow

1. Call peer_cash_capabilities before naming a payout platform or currency.
2. Call peer_cash_estimate. Treat it as approximate: the binding Chainlink rate resolves when a buyer fills.
3. Call peer_cash_prepare with a Base USDC amount in 6-decimal base units and one or more payout legs.
4. Show the returned transaction plan and obtain explicit user approval.
5. Submit each transaction in order through the host wallet and confirm it on Base.
6. Call peer_cash_finalize with the confirmed createDeposit transaction hash.
7. If accessPolicyRequired was true, call peer_cash_prepare_access_policy and submit that transaction with the depositor wallet.
8. Persist the returned depositId for order tracking and recovery.

Unknown transaction outcomes must be inspected before any resubmission. Peer Cash errors include a code, retryability, remediation, and recovery evidence for this purpose.

Development

bun install
bun run ci

Requires Node.js 22 or newer.

Validate the portable package separately from the server test suite:

npx skills-ref validate skills/peer-cash