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

Reads work everywhere

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.

Trade-building splits by surface

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.

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.

Try it

Read pairs and PnL (any surface)

What's my Avantis open positions and PnL on Base?

Open long (CLI harness)

Open a 10x long BTC/USD with 100 USDC collateral on Avantis

Limit order (CLI harness)

Place a limit long on ETH/USD at 3000 with 50 USDC at 5x

Manage trade (CLI harness)

Close my BTC/USD position on Avantis

Chat-only fallback

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.

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.

Reference

Full plugin spec on GitHub

Endpoint inventory, parameters, unit/scaling rules, batching guidance, chat-only UI fallback, and error handling.