Junto Mcp

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

Quick Start

npm install -g junto-mcp

Set your provider API key:

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

Run as CLI (human mode):

junto pay 25.00 [email protected]junto charge 10.00 "Coffee"junto balance

Run as MCP server (for AI clients):

junto --mcp

Portuguese / Portugues

Junto auto-detects your system language, or set manually:

JUNTO_LANG=pt-BR junto ajudajunto pagar 25.00 [email protected]junto cobrar 10.00 "Cafe"junto saldo

See CLI.md for the full command reference in both languages.

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).

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

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
• Verified: charge, status, and payment flows tested with real Pix transactions (March 2026)

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.tsimport { 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              # Guardrail unit testsnpm run test:smoke    # Full flow smoke tests (mock provider)

Live testing with real Pix

# Create a Pix charge (R$1.00)WOOVI_APP_ID=your-key npx tsx test/live-pix.ts charge 100 "Test charge"
# Check statusWOOVI_APP_ID=your-key npx tsx test/live-pix.ts status <correlation-id>
# Send a Pix paymentWOOVI_APP_ID=your-key npx tsx test/live-pix.ts pay 100 [email protected] EMAIL
# RefundWOOVI_APP_ID=your-key npx tsx test/live-pix.ts refund <correlation-id>

Interactive demo

npx tsx demo/demo.ts          # Full demo with typewriter narration + real API callsnpx tsx demo/demo.ts --fast   # Fast mode for rehearsals

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

• Core MCP server with universal tool interface
• Woovi/OpenPix provider (Pix) — live-tested with real transactions
• Guardrails (daily limits, per-tx max, HITL confirmation)
• Audit ledger
• junto-skill (Claude behavioral layer)
• Interactive demo (npx tsx demo/demo.ts)
• Ebanx provider (Pix payouts, Boleto, Cards — Brazil + LATAM)
• 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 — Ebanx, 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