@sly/mcp-server

Model Context Protocol (MCP) server for Sly, enabling Claude Desktop integration.

What is MCP?

Model Context Protocol is Anthropic's open protocol for connecting AI assistants like Claude to external tools and data sources. This server exposes Sly payment operations as MCP tools that Claude can use.

Installation

# From npm (when published)
npm install -g @sly/mcp-server

# From source
cd packages/mcp-server
pnpm build
pnpm link --global

Configuration

Claude Desktop Setup

Add to your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "sly": {
      "command": "npx",
      "args": ["@sly/mcp-server"],
      "env": {
        "SLY_API_KEY": "pk_test_...",
        "SLY_ENVIRONMENT": "sandbox"
      }
    }
  }
}

Environment Variables

• SLY_API_KEY (required): Your Sly API key
• SLY_ENVIRONMENT (optional): Environment to use
  • sandbox (default): Local development, no real transactions
  • testnet: Testnet with real blockchain transactions
  • production: Production environment

Available Tools

Once configured, Claude Desktop will have access to 22 tools across 5 categories:

Settlement Tools

get_settlement_quote

Get a settlement quote for cross-border payment.

Parameters:

• fromCurrency: Source currency (USD, BRL, MXN, USDC)
• toCurrency: Destination currency (USD, BRL, MXN, USDC)
• amount: Amount to convert
• rail (optional): Settlement rail (pix, spei, wire, usdc)

create_settlement

Execute a settlement using a quote.

Parameters:

• quoteId: Quote ID from get_settlement_quote
• destinationAccountId: Destination account ID
• metadata (optional): Additional metadata

get_settlement_status

Check the status of a settlement.

Parameters:

• settlementId: Settlement ID

UCP (Universal Commerce Protocol) Tools

ucp_discover

Discover a merchant's UCP capabilities.

ucp_get_quote

Get an FX quote for settlement to Brazil (Pix) or Mexico (SPEI).

ucp_acquire_token

Acquire a settlement token that locks in an FX rate for 15 minutes.

ucp_settle

Complete a settlement using a previously acquired token.

ucp_get_settlement

Check the status of a UCP settlement.

ucp_list_corridors

List available settlement corridors.

Agent Management Tools

list_accounts

List accounts for the current tenant. Use to find a business account for agent creation.

create_agent

Register a new AI agent under a business account.

Parameters:

• accountId: UUID of the parent business account
• name: Name for the agent
• description (optional): What the agent does

verify_agent

Verify an agent at a KYA tier (1-3). Higher tiers unlock higher spending limits.

get_agent

Get agent details including KYA tier, status, and permissions.

get_agent_limits

Get spending limits and current usage for an agent.

AP2 (Agent-to-Agent Protocol) Mandate Tools

ap2_create_mandate

Create a spending mandate that authorizes an agent to spend up to a budget.

Parameters:

• mandate_id: Unique mandate identifier
• agent_id: Agent UUID
• account_id: Funding account UUID
• authorized_amount: Maximum spend amount
• currency (optional): Currency (default: USD)
• mandate_type (optional): intent | cart | payment

ap2_get_mandate

Get mandate details including execution history and remaining budget.

ap2_execute_mandate

Execute a payment against a mandate. Deducts from the budget and creates a transfer.

ap2_list_mandates

List mandates with optional filtering by status, agent, or account.

ACP (Agentic Commerce Protocol) Checkout Tools

acp_create_checkout

Create a checkout session with items for an agent to purchase.

Parameters:

• checkout_id: Unique checkout identifier
• agent_id: Agent UUID
• merchant_id: Merchant identifier
• items: Array of items (name, quantity, unit_price, total_price)
• tax_amount, shipping_amount (optional): Additional charges

acp_get_checkout

Get checkout details including items, totals, and status.

acp_complete_checkout

Complete and pay for a checkout.

acp_list_checkouts

List checkouts with optional filtering.

Shopping Demo Flow

With all tools available, Claude can run the full shopping demo:

User: List my accounts and find a business account

Claude: [Uses list_accounts] Found "TechCorp Trading" (acct_xxx)

User: Create a Shopping Agent under that account

Claude: [Uses create_agent] Created "Shopping Agent" (agent_xxx)

User: Verify the agent at KYA Tier 1

Claude: [Uses verify_agent] Agent verified at Tier 1

User: Create a $500 spending mandate for the agent

Claude: [Uses ap2_create_mandate] Mandate created with $500 budget

User: Create a checkout with sneakers ($199) and a backpack ($89)

Claude: [Uses acp_create_checkout] Checkout created, total: $288

User: Complete the checkout and record the payment

Claude: [Uses acp_complete_checkout, ap2_execute_mandate]
       Checkout completed! $288 deducted from mandate.
       Remaining budget: $212

Development

# Install dependencies
pnpm install

# Build
pnpm build

# Run locally
SLY_API_KEY=pk_test_xxx pnpm start

# Run tests
pnpm test

# Watch mode
pnpm dev

Testing with MCP Inspector

The MCP Inspector is a tool for debugging MCP servers:

# Install inspector
npm install -g @modelcontextprotocol/inspector

# Run server in inspector
SLY_API_KEY=pk_test_xxx mcp-inspector npx @sly/mcp-server

Architecture

┌─────────────────┐
│ Claude Desktop  │
└────────┬────────┘
         │ MCP Protocol (stdio)
┌────────┴────────┐
│  MCP Server     │
│  (This package) │
└────────┬────────┘
         │ HTTP
┌────────┴────────┐
│  Sly API        │
│  (api.sly.dev)  │
└─────────────────┘

License

MIT