Junto

The payment protocol for people and agents.

Send and receive money through any AI assistant. Any payment rail. Built-in guardrails.

Named after Benjamin Franklin's Junto — a society of tradesmen who built civic infrastructure together. Different providers, same table, mutual benefit.

Why

AI assistants are starting to move real money — paying invoices, splitting bills, sending transfers. But every payment provider has a different API, different auth, different settlement times. Nobody should have to teach their assistant how Pix works vs Stripe vs Wise.

Junto fixes that with one MCP server that:

• Exposes a universal payment toolkit to any MCP-compatible client (Claude, Cursor, custom agents)
• Routes to the right provider based on currency, country, and rail
• Enforces spending limits so agents can't go rogue
• Supports human-in-the-loop confirmation for high-value transactions
• Logs every action for audit and accountability

Tools

| Tool | Description | |---|---| | pay | Send money to a destination (Pix key, email, IBAN, etc.) | | charge | Create a payment request / invoice / QR code | | status | Check payment status by correlation ID | | refund | Reverse a completed transaction | | balance | Check available funds on a provider | | providers | List configured providers and their capabilities | | limits | Show spending limits and today's usage |

Quick Start

npm install -g junto-mcp

Set your provider API key:

export WOOVI_APP_ID="your-woovi-app-id"

Run:

junto-mcp

Add to Claude Desktop or Cursor

{
  "mcpServers": {
    "junto": {
      "command": "npx",
      "args": ["-y", "junto-mcp"],
      "env": {
        "WOOVI_APP_ID": "your-woovi-app-id"
      }
    }
  }
}

That's it. Your AI assistant now has payment tools.

Guardrails

All amounts are in cents (smallest currency unit).

| Setting | Env Var | Default | Meaning | |---|---|---|---| | Daily limit | JUNTO_DAILY_LIMIT | 50000 (R$500) | Max total spend per day | | Per-tx max | JUNTO_PER_TX_MAX | 20000 (R$200) | Max single transaction | | Confirm above | JUNTO_CONFIRM_ABOVE | 5000 (R$50) | Ask human before sending | | Allowed providers | JUNTO_ALLOWED_PROVIDERS | (all) | Comma-separated allowlist | | Allowed destinations | JUNTO_ALLOWED_DESTINATIONS | (all) | Comma-separated type allowlist |

When an agent tries to send above the JUNTO_CONFIRM_ABOVE threshold, the server pauses and returns a confirmation prompt. The agent must relay this to the user and get approval before proceeding.

⚠️ Confirmation required

  Amount:      BRL 150.00
  To:          [email protected]
  Reason:      Amount (15000 cents) exceeds confirmation threshold (5000 cents)

Please confirm with the user before proceeding.

Architecture

┌─────────────────────────────────────┐
│  MCP Client (Claude, Cursor, etc.)  │
└──────────────┬──────────────────────┘
               │ MCP Protocol (stdio)
┌──────────────▼──────────────────────┐
│           junto-mcp                 │
│                                     │
│  ┌───────────┐  ┌────────────────┐  │
│  │  Router    │  │  Guardrails    │  │
│  │  (picks    │  │  (spend caps,  │  │
│  │  provider) │  │  HITL confirm, │  │
│  │           │  │  audit log)    │  │
│  └─────┬─────┘  └────────────────┘  │
│        │                            │
│  ┌─────▼─────────────────────────┐  │
│  │  Provider Adapters            │  │
│  │  ┌────────┐ ┌──────┐ ┌────┐  │  │
│  │  │ Woovi  │ │Stripe│ │Wise│  │  │
│  │  └────────┘ └──────┘ └────┘  │  │
│  └───────────────────────────────┘  │
│                                     │
│  ┌───────────────────────────────┐  │
│  │  Audit Ledger (JSONL)         │  │
│  └───────────────────────────────┘  │
└─────────────────────────────────────┘

Providers

| Provider | Region | Rails | Status | |---|---|---|---| | Woovi/OpenPix | Brazil | Pix | 🟢 Shipped | | Belvo | Brazil | Open Finance (all banks) | 🟡 Next | | Stripe | Global | Cards, ACH, SEPA | 🟡 Next | | Wise | Global | Bank transfers | 🔴 Planned | | Mercado Pago | LATAM | Pix, Cards | 🔴 Planned | | PayPal | Global | Email-based | 🔴 Planned |

Why Woovi/Pix first?

• Pix settles instantly (perfect for demos and real use)
• Brazil's Central Bank mandates open APIs for payments
• 180M+ Pix users, 80B+ transactions in 2025
• Pix Automático (launched June 2025) enables recurring payments
• Low fees, no intermediaries

Demo

You:   "Pay R$25 to [email protected] via Pix"

Agent:  I'll send the following payment:
          Amount: R$ 25,00
          To: [email protected] (Pix)
          Via: Woovi
        Shall I go ahead?

You:   "Yes"

Agent:  Done! Payment sent.
          Amount: R$ 25,00
          To: [email protected]
          Via: Pix (Woovi)
          Status: Completed
          ID: junto-1739612345-a1b2c3

Adding a Provider

Each provider is a single file implementing the PaymentProvider interface:

// src/providers/your-provider.ts
import { PaymentProvider } from "../types.js";

export class YourProvider implements PaymentProvider {
  name = "your-provider";
  supportedCurrencies = ["USD"];
  supportedRails = ["card"];
  settlementTime = "1-3 days";

  async pay(req) { /* send money */ }
  async charge(req) { /* create invoice */ }
  async status(id) { /* check status */ }
  async refund(id) { /* reverse payment */ }
  async balance() { /* check funds */ }
  info() { /* return capabilities */ }
}

Copy src/providers/_template.ts to get started, then register your provider in src/index.ts.

Testing

npm test

Runs guardrail tests covering: amount limits, daily budget tracking, confirmation thresholds, provider allowlists, and destination type filtering.

Audit Log

Every transaction is logged to ~/.junto/audit-YYYY-MM-DD.jsonl:

{
  "timestamp": "2026-02-15T14:32:07Z",
  "type": "payment",
  "action": "pay",
  "tool": "pay",
  "amount": 2500,
  "currency": "BRL",
  "provider": "woovi",
  "destination": "[email protected]",
  "status": "executed"
}

Roadmap

• [x] Core MCP server with universal tool interface
• [x] Woovi/OpenPix provider (Pix)
• [x] Guardrails (daily limits, per-tx max, HITL confirmation)
• [x] Audit ledger
• [x] junto-skill (Claude behavioral layer)
• [ ] Belvo provider (Open Finance — all Brazilian banks)
• [ ] Stripe provider (Cards, ACH, SEPA)
• [ ] junto-approve (Telegram/WhatsApp confirmation for HITL)
• [ ] junto-dashboard (web UI for tx history and limits)
• [ ] junto-compute (agent-to-agent budget delegation)
• [ ] AP2 compatibility layer (Google Agent Payments Protocol)
• [ ] Wise provider (international bank transfers)

Contributing

We need help with:

• Provider adapters — Stripe, Wise, Belvo, Mercado Pago, PayPal, UPI
• Routing logic — Cheapest vs fastest vs most reliable provider selection
• HITL patterns — Approval flows across different MCP clients
• Security audit — Review of the guardrails and auth system
• Multi-currency — FX handling, cross-border routing
• Docs — Compliance and regulatory guides per region

License

MIT