docs: Add Spraay Batch Payments MCP Extension Tutorial (#7525)

Signed-off-by: plagtech <mngoswp@gmail.com>

documentation/docs/tutorials/spraay-mcp.md

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+---
+title: Spraay x402 Extension
+description: Add Spraay x402 MCP Server as a goose Extension for batch crypto payments, onchain data, and AI model access
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+This tutorial covers how to add the [Spraay x402 MCP Server](https://github.com/plagtech/spraay-x402-mcp) as a goose extension for batch cryptocurrency payments, onchain data, and AI model access on Base.
+
+With the Spraay extension, goose can send ETH and ERC-20 tokens to up to **200 recipients in a single transaction**, query live token prices, check wallet balances, resolve ENS names, get swap quotes, and chat with 200+ AI models — all pay-per-call via the [x402 protocol](https://x402.org).
+
+## Supported Tools
+
+The Spraay x402 MCP Server provides the following tools:
+
+| Tool | Cost | Description |
+|------|------|-------------|
+| `spraay_chat` | $0.005 | AI chat via 200+ models (GPT-4, Claude, Llama, Gemini) |
+| `spraay_models` | $0.001 | List available AI models with pricing |
+| `spraay_batch_execute` | $0.01 | Batch USDC payments to multiple recipients |
+| `spraay_batch_estimate` | $0.001 | Estimate gas for batch payments |
+| `spraay_swap_quote` | $0.002 | Uniswap V3 swap quotes on Base |
+| `spraay_tokens` | $0.001 | List supported tokens on Base |
+| `spraay_prices` | $0.002 | Live onchain token prices (Uniswap V3) |
+| `spraay_balances` | $0.002 | ETH + ERC-20 balances for any address |
+| `spraay_resolve` | $0.001 | Resolve ENS names and Basenames to addresses |
+
+:::info
+AI agents pay USDC per request via the x402 protocol. No API keys or accounts needed — just a wallet with USDC on Base.
+:::
+
+## Setup
+
+### Prerequisites
+
+- Git and Node.js installed
+- A wallet private key with USDC on Base (for x402 micropayments)
+
+### Install the MCP Server
+
+```bash
+git clone https://github.com/plagtech/spraay-x402-mcp.git
+cd spraay-x402-mcp
+npm install
+npm run build
+```
+
+### Configuration
+
+<Tabs>
+<TabItem value="ui" label="goose Desktop">
+
+1. Click the **Extensions** icon in the sidebar
+2. Click **Add custom extension**
+3. Select **Command-line Extension**
+4. Fill in the following:
+   - **Name**: `spraay`
+   - **Command**: `node /absolute/path/to/spraay-x402-mcp/dist/index.js`
+   - **Timeout**: `300`
+5. Add environment variable:
+   - **Name**: `EVM_PRIVATE_KEY`
+   - **Value**: Your wallet private key (with USDC on Base)
+
+</TabItem>
+<TabItem value="cli" label="goose CLI">
+
+```
+goose configure
+```
+
+Choose **Add Extension** → **Command-line Extension** and configure:
+
+```
+┌   goose-configure
+│
+│   ◇  What would you like to call this extension?
+│   spraay
+│
+│   ◇  What command should be run?
+│   node /absolute/path/to/spraay-x402-mcp/dist/index.js
+│
+│   ◇  Please set the timeout for this tool (in secs):
+│   300
+│
+│   ◇  Would you like to add environment variables?
+│   Yes
+│
+│   ◇  Environment variable name:
+│   EVM_PRIVATE_KEY
+│
+│   ◇  Environment variable value:
+│   ▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪
+│
+│   └  Added spraay extension
+```
+
+</TabItem>
+</Tabs>
+
+## Example Usage
+
+### Check Token Prices
+
+```
+What's the current price of ETH on Base?
+```
+
+goose will use the `spraay_prices` tool to fetch live onchain prices from Uniswap V3.
+
+### Check Wallet Balances
+
+```
+Check the USDC balance of vitalik.eth
+```
+
+goose will use `spraay_resolve` to resolve the ENS name, then `spraay_balances` to fetch balances.
+
+### Get a Swap Quote
+
+```
+Get me a swap quote for 100 USDC to WETH on Base
+```
+
+goose will use `spraay_swap_quote` to fetch a live quote from Uniswap V3.
+
+### Batch Send USDC
+
+```
+Send 10 USDC each to these wallets:
+0x742d35Cc6634C0532925a3b844Bc9e7595f2bD18
+0x53d284357ec70cE289D6D64134DfAc8E511c8a3D
+0xFBb1b73C4f0BDa4f67dcA266ce6Ef42f520fBB98
+```
+
+goose will use `spraay_batch_execute` to process all payments in a single transaction.
+
+### Chat with AI Models
+
+```
+Using spraay, ask GPT-4 to explain what x402 is
+```
+
+goose will use `spraay_chat` to query from 200+ available AI models.
+
+## How It Works
+
+1. You ask goose → goose calls a Spraay tool (e.g. `spraay_prices`)
+2. MCP server sends request to `gateway.spraay.app`
+3. Gateway returns HTTP 402 + payment requirements
+4. x402 client auto-signs USDC payment on Base
+5. Gateway verifies payment and returns data
+
+Each call costs $0.001–$0.01 in USDC. No API keys, no accounts.
+
+## Resources
+
+- [Spraay App](https://spraay.app) — Multi-chain batch payments (10 chains)
+- [Spraay x402 Gateway](https://gateway.spraay.app) — AI agent payment gateway
+- [GitHub](https://github.com/plagtech/spraay-x402-mcp) — MCP server source code
+- [x402 Protocol](https://x402.org) — The payment standard
+- [Smart Contract on BaseScan](https://basescan.org/address/0x1646452F98E36A3c9Cfc3eDD8868221E207B5eEC)