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

# Swap Tokens

> Swap between tokens on supported mainnet chains using Base MCP

## What you can ask

```text theme={null}
Swap 100 USDC for ETH on Base
```

```text theme={null}
Buy $50 of ETH with USDC
```

```text theme={null}
Trade 0.01 ETH for USDC
```

```text theme={null}
Convert all my USDC to ETH
```

## How it works

The `swap` tool prepares a token swap and requires your approval in Base Account. Swaps are only supported on mainnet chains — not on testnets.

| Parameter   | Required | What it does                                                                                            |
| ----------- | -------- | ------------------------------------------------------------------------------------------------------- |
| `fromAsset` | Yes      | Token to swap from — symbol (`USDC`) or contract address                                                |
| `toAsset`   | Yes      | Token to swap to — symbol (`ETH`) or contract address                                                   |
| `amount`    | Yes      | Amount of `fromAsset` to swap (human-readable decimal)                                                  |
| `chain`     | Yes      | Target mainnet chain, e.g. `base`, `ethereum`, `arbitrum`, `optimism`, `polygon`, `bsc`, or `avalanche` |

<Note>
  Testnet swaps are not supported. If you need to test, use `send` on `base-sepolia` instead.
</Note>

## Approval flow

Same as sending — every swap requires approval in Base Account. Your assistant will give you a link to review the swap details before anything is signed.

## Related guides

<CardGroup cols={2}>
  <Card title="Send tokens" icon="paper-plane" href="/agents/guides/send-tokens">
    Send tokens directly to another address.
  </Card>

  <Card title="Check balance" icon="wallet" href="/agents/guides/check-balance">
    Verify balances before swapping.
  </Card>
</CardGroup>