> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mandate.md/llms.txt
> Use this file to discover all available pages before exploring further.

# GOAT SDK Plugin

> Add Mandate policy enforcement to your GOAT SDK agent with the @mandate.md/goat-plugin package.

## What is the GOAT SDK plugin?

The `@mandate.md/goat-plugin` package wraps Mandate's policy engine as a GOAT SDK plugin. It exposes two tools: `mandate_transfer` for ERC20 transfers and `mandate_x402_pay` for x402 payment flows. Every tool call validates against your Mandate spending policies before signing or broadcasting.

The plugin extends `PluginBase<EVMWalletClient>` and works with any EVM chain supported by GOAT.

## Installation

```bash theme={null}
bun add @mandate.md/goat-plugin @goat-sdk/core
```

`@goat-sdk/core` is a peer dependency (>=0.3.0). Install it alongside the plugin.

## Usage

```typescript theme={null}
import { mandate } from '@mandate.md/goat-plugin';
import { createWalletClient, http } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import { baseSepolia } from 'viem/chains';

const walletClient = createWalletClient({
  account: privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`),
  chain: baseSepolia,
  transport: http(),
});

const mandatePlugin = mandate({
  runtimeKey: process.env.MANDATE_RUNTIME_KEY!,
  privateKey: process.env.PRIVATE_KEY! as `0x${string}`,
  chainId: 84532,
  rpcUrl: 'https://sepolia.base.org',
});
```

Pass the plugin to your GOAT agent's plugin list. The agent can now call `mandate_transfer` and `mandate_x402_pay` as tools.

## Tools

| Tool               | Description                                                                                                                |
| ------------------ | -------------------------------------------------------------------------------------------------------------------------- |
| `mandate_transfer` | Transfer ERC20 tokens with policy enforcement. Accepts `to`, `amount`, `tokenAddress`, and optional `waitForConfirmation`. |
| `mandate_x402_pay` | Pay for an x402-gated resource. Accepts `url` and optional `headers`.                                                      |

Both tools create a `MandateWallet` internally, validate the transaction against the Mandate API, sign locally, and broadcast. Your private key never leaves the process.

## Configuration

| Parameter    | Type                | Required | Description                                              |
| ------------ | ------------------- | -------- | -------------------------------------------------------- |
| `runtimeKey` | `string`            | Yes      | Mandate runtime key (`mndt_live_...` or `mndt_test_...`) |
| `privateKey` | `` `0x${string}` `` | Yes      | Agent wallet private key (hex, with `0x` prefix)         |
| `chainId`    | `number`            | No       | EVM chain ID. Defaults to `84532` (Base Sepolia).        |
| `rpcUrl`     | `string`            | No       | RPC endpoint URL. Defaults to the chain's public RPC.    |

## Error handling

The plugin throws plain `Error` objects with descriptive messages. This matches GOAT SDK conventions where tool errors surface as strings to the LLM.

```typescript theme={null}
// Policy block:
// "Transfer blocked by Mandate policy: daily_limit_exceeded"

// Approval required:
// "Transfer requires approval. IntentId: int_abc123"
```

If your agent needs structured error handling, use the `@mandate.md/sdk` directly. The SDK throws typed errors: `PolicyBlockedError`, `ApprovalRequiredError`, and `CircuitBreakerError`.

<Warning>
  Store `runtimeKey` and `privateKey` in environment variables. Never hardcode credentials in source files.
</Warning>

## Next Steps

<CardGroup cols={2}>
  <Card title="Integrations Overview" icon="grid-2" href="/integrations/overview">
    Compare all supported agent frameworks and choose the right one.
  </Card>

  <Card title="MandateWallet" icon="wallet" href="/sdk/mandate-wallet">
    Use MandateWallet directly for full control over the validate-sign-broadcast flow.
  </Card>

  <Card title="Handle Errors" icon="triangle-exclamation" href="/guides/handle-errors">
    Learn how to catch and respond to every Mandate error type.
  </Card>
</CardGroup>