> ## Documentation Index
> Fetch the complete documentation index at: https://base-a060aa97-fix-dead-service-links.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Avantis

> Perpetual futures on Base via the Avantis tx-builder. Reads work on every surface; trade-building uses a CLI harness or the Avantis web UI.

Avantis is a perpetual futures DEX on Base mainnet. The plugin reads market data, positions, and PnL from `data.avantisfi.com`, `core.avantisfi.com`, and `api.avantisfi.com` (allowlisted for Base MCP `web_request`), and builds unsigned trade calldata from `tx-builder.avantisfi.com` for execution through Base MCP's `send_calls`. Collateral is USDC; ETH is used only for gas and execution fees.

**Chain:** Base mainnet.

**Operations:** open trade (market, limit, stop-limit, zero-fee), close, cancel, update margin, set TP/SL, approve USDC, set/remove delegate, plus reads for pairs, positions, limit orders, and PnL history.

## Surface routing

<CardGroup cols={2}>
  <Card title="Reads work everywhere" icon="circle-check">
    Pair info, leverage rules, fees, open positions, limit orders, and PnL history are fetched through Base MCP `web_request` on chat-only surfaces (ChatGPT, Claude.ai) or directly via the harness HTTP tool in Claude Code, Codex, and Cursor terminal.
  </Card>

  <Card title="Trade-building splits by surface" icon="route">
    In CLI harnesses, the plugin calls the Avantis tx-builder and submits unsigned calldata through `send_calls`. On chat-only surfaces, it links the user to the Avantis web UI for the relevant pair instead.
  </Card>
</CardGroup>

<Note>
  Only `tx-builder.avantisfi.com` is gated to CLI harnesses. View-only Avantis APIs (`data`, `core`, `history`) are on the Base MCP `web_request` allowlist and work on every supported surface.
</Note>

## Try it

```text Read pairs and PnL (any surface) theme={null}
What's my Avantis open positions and PnL on Base?
```

```text Open long (CLI harness) theme={null}
Open a 10x long BTC/USD with 100 USDC collateral on Avantis
```

```text Limit order (CLI harness) theme={null}
Place a limit long on ETH/USD at 3000 with 50 USDC at 5x
```

```text Manage trade (CLI harness) theme={null}
Close my BTC/USD position on Avantis
```

```text Chat-only fallback theme={null}
Take me to the ETH/USD market on Avantis
```

When the request needs tx-builder calldata and the current surface is chat-only, the assistant summarizes what you'd be signing and hands you a deep link of the form `https://www.avantisfi.com/trade?asset=<SYMBOL>-USD` (for example, `https://www.avantisfi.com/trade?asset=ETH-USD`) to complete the trade in the Avantis UI.

## Pattern

Every prepare endpoint returns a single-call envelope (`{ ok, data: { to, value, data, chainId } }`) that maps to a Base MCP `send_calls` call with `chain: "base"`. Approval and trade can be batched into one approval. The plugin reads `/v2/trading` to validate pair, leverage, and minimum notional before building the open call, and reads `core /user-data` to resolve real position/order indices for management actions.

<Note>
  No additional MCP server is required. View-only Avantis APIs are reached through Base MCP `web_request` on chat-only surfaces (or directly from the harness shell in CLI environments). Tx-builder calldata is built and submitted from CLI harnesses; on chat-only surfaces the assistant links to the Avantis UI instead.
</Note>

## Reference

<Card title="Full plugin spec on GitHub" icon="github" href="https://github.com/base/skills/blob/main/skills/base-mcp/plugins/avantis.md">
  Endpoint inventory, parameters, unit/scaling rules, batching guidance, chat-only UI fallback, and error handling.
</Card>