# 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](https://en.wikipedia.org/wiki/Junto_(club)) — 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
```bash
npm install -g junto-mcp
```
Set your provider API key:
```bash
export WOOVI_APP_ID="your-woovi-app-id"
```
Run:
```bash
junto-mcp
```
### Add to Claude Desktop or Cursor
```json
{
"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: maria@email.com
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$25 to maria@email.com via Pix"
Agent: I'll send the following payment:
Amount: R$ 25,00
To: maria@email.com (Pix)
Via: Woovi
Shall I go ahead?
You: "Yes"
Agent: Done! Payment sent.
Amount: R$ 25,00
To: maria@email.com
Via: Pix (Woovi)
Status: Completed
ID: junto-1739612345-a1b2c3
```
## Adding a Provider
Each provider is a single file implementing the `PaymentProvider` interface:
```typescript
// 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
```bash
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`:
```json
{
"timestamp": "2026-02-15T14:32:07Z",
"type": "payment",
"action": "pay",
"tool": "pay",
"amount": 2500,
"currency": "BRL",
"provider": "woovi",
"destination": "maria@email.com",
"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
