# xgas-mcp > MCP connector for the xGas Orbit L4 and X Money: vault bridge, P2P OTC desk, NGU curves, fiat ramps, and cross-chain X Money swaps. Prepares transactions for your own wallet to sign; with Privy configured it can also sign as an agent wallet of its own. Latest version **0.4.1** (published 2026-09-22) · GPL-2.0-or-later license · 0 weekly downloads ## Install ```sh npm install xgas-mcp pnpm add xgas-mcp yarn add xgas-mcp bun add xgas-mcp ``` ## Health **Score 55/100 (C)** — status: active. Positive: no vulnerabilities; recently updated; high maintenance score. Warnings: low downloads; no types; no esm support; pre 1.0. ## Facts | | | |---|---| | Version | 0.4.1 | | Published | 2026-09-22 | | First published | 2026-09-22 | | Weekly downloads | 0 | | License | GPL-2.0-or-later | | TypeScript types | none | | Module format | CommonJS | | Dependencies | 0 | | Known vulnerabilities | 0 | | Install scripts | no | | Author | staccoverflow | | Maintainers | staccoverflow123 | | Keywords | mcp, model-context-protocol, claude, ethereum, arbitrum-orbit, xmoney, defi, cross-chain, intents, viem | ## Links - npm: https://www.npmjs.com/package/xgas-mcp - Repository: https://github.com/staccoverflow/xgas-app - Homepage: https://xgas.dev - Issues: https://github.com/staccoverflow/xgas-app/issues - npm.io page: https://npm.io/package/xgas-mcp ## Recent versions - 0.4.1 (latest) — 2026-09-22 - 0.4.0 — 2026-09-22 - 0.3.0 — 2026-09-22 - 0.2.2 — 2026-09-22 - 0.2.1 — 2026-09-22 ## README # xgas-mcp An MCP server over the xGas stack: the USDG vault bridge on Robinhood Chain (4663), the P2P OTC desk and NGU curves on xGas Orbit L4 (466301), a teller layer that routes between dollars and $xMoney, and XSwap: X Money in, anything on any EVM chain out, and the other way round. 52 tools, all grounded in a deployment file and the live chains. By default nothing is custodial: the connector prepares transactions and your own wallet signs them. The three `wallet_*` tools are the deliberate exception, and they only exist when you configure Privy. ## Use it without cloning Hosted, no install — point a host at the remote server: ``` https://xgas.dev/mcp ``` Or run it locally over stdio: ```bash npx -y xgas-mcp ``` ## Run it ```bash npm install npm start # stdio npm run check # smoke test over real MCP stdio, against the live chains npm run e2e # a whole X Money swap on an anvil fork: open, bid, accept, claim, confirm, withdraw ``` Host config: ```json { "mcpServers": { "xgas": { "command": "npx", "args": ["-y", "xgas-mcp"] } } } ``` Environment overrides, all optional: | Variable | Default | Use | |---|---|---| | `XGAS_DEPLOYMENT` | `../src/contracts/l4-deployment.json` | point at another deployment file | | `XGAS_PARENT_RPC` | `parentRpcUrl` from the deployment | parent chain RPC | | `XGAS_RPC` | `publicRpcUrl` from the deployment | xGas L4 RPC | | `XGAS_API` | `https://xgas.dev` | the host that runs the Outbox executor and serves `/api/l4-info` | | `XGAS_NGU_LAUNCHER` | unset | the NguLauncher address, until it is in the deployment file | | `XGAS_MCP_DATA` | `/data` or `~/.xgas-mcp` | where idempotency keys and ramp state live | | `XSWAP_INTENTS` | `0xf8B4…9a35` | the X-Money-in escrow on the parent chain | | `XSWAP_ASKS` | `0x0a33…Cd13` | the X-Money-out escrow on the parent chain | ## XSwap: X Money in, anything out `quote_xswap` and `prepare_xswap_out` escrow X Money against an order (chain, asset, amount, recipient) hashed the way every solver hashes it. Solvers bid the price down, the lowest ask wins, and whatever the bidding saves comes back to the payer as credit. `prepare_xswap_in` is the other direction: an ask is a price, not an escrow, and the buyer's X Money is held before the seller sends anything. Solving is permissionless. There is no allow-list: `prepare_xswap_action` will prepare a bid and a claim for any address, the bond is the permission, and losing a dispute is the cost. `xswap_reputation` is only ever the sum of finished jobs, and it says "new here" rather than pretending a number it does not have. The connector cannot see the destination chain. It never claims an asset arrived; the challenge window and the bond are what stand in for that. ## Design rules **Non-custodial.** The connector holds no keys and signs nothing. Every write comes back as an unsigned transaction envelope; `submit_*` is a relay for an already-signed payload. The only key in the system is the host's `L3_EXECUTOR_KEY`, which can only execute already-claimable Outbox withdrawals — a permissionless call. **Quote, review, approve, submit.** Each `prepare_*` returns the approval screen a non-custodial connector owes you: exact action, asset, amount, counterparty (address and X handle where known), every fee with the net, the finality timeline, and what cannot be undone. Nothing auto-approves. **Idempotency.** Every `submit_*` takes a key. A repeat returns the first hash instead of sending a second transaction. **Reads are free.** Balances, NAV, quotes, the order book and withdrawal status need no approval and no signature. **Dead ends are answers.** An empty order book, a sold-out curve, a warp route that was never deployed — each comes back as a stated result with the recourse, never as a silent failure or an invented number. **The fiat leg is instructions, not a transaction.** OTC dollar payments happen between X handles on X Money. The connector watches the escrow and says so; it never claims the money moved. ## Tool surface **Chain and account** — `get_chain_info`, `get_balance`, `get_vault_nav`, `get_fee_schedule` **Bridge in (USDG → $xMoney)** — `quote_enter`, `prepare_enter`, `submit_enter`, `get_enter_status` **Bridge out ($xMoney → USDG)** — `quote_exit`, `prepare_exit`, `submit_exit`, `get_exit_status`, `claim_exit`, `prepare_redeem`, `submit_redeem` **OTC desk** — `list_orders`, `get_order`, `get_trade`, `quote_trade`, `post_ask`, `post_bid`, `take_ask`, `take_bid`, `release_trade`, `reclaim_timeout`, `cancel_order`, `submit_otc` **NGU curves** — `list_ngu_tokens`, `get_ngu_token`, `quote_ngu_buy`, `prepare_ngu_buy`, `quote_ngu_sell`, `prepare_ngu_sell`, `prepare_ngu_donate`, `launch_ngu_token`, `submit_ngu` **Ramps** — `ramp_quote`, `ramp_start`, `ramp_status` ## Things the chain taught us, that the spec had wrong - **The deployed vault is older than `contracts/src/XMoney.sol`.** `0xa924…a97E` has no `enterRollupToL3`, `setL4RetryableParams`, `l4GasLimit`, `l4MaxFeePerGas` or `totalXMoneyBridgedToL4`. The connector exposes only what the bytecode actually has, and reads the lifetime counters tolerantly. - **Exiting costs more than the exit rake.** The Outbox pays out of the Bridge, which is a transfer *out* of the bridge system, so the 0.01% xMoney tax applies on top of the 0.01% USDG rake. `quote_exit` charges both. - **`NguToken.buy` refunds overpayment.** The spec said it refunds nothing. `prepare_ngu_buy` therefore sends a small buffer (default 1%) so a buyer who gets front-run by one curve step does not revert with `Underpaid`. - **`src/contracts/nguAbis.ts` declared `basePrice` as `uint16`.** Reading it threw "not in safe integer range" against a real 1e16 price. Fixed to `uint256`. ## Verification `npm run check` exercises the real MCP stdio transport against both live chains. The NGU tools have no launcher on xGas yet, so they were verified against a local anvil at chain id 466301 with a real `NguLauncher` and curve — buy with buffer, sell with `minOut`, donate, and an idempotent replay. `scripts/ngu-roundtrip.mjs` reruns that; its header has the setup commands. The predicted post-donation floor matched the chain exactly, and the sell basis correctly flipped from `floor` to `lastPrice` once the donation lifted the floor above the last paid price. ## Status All three items the spec left open are closed. 1. **Wallet connection.** `server.js` serves the read and prepare tools at `GET /api/connector` and `POST /api/connector/:tool` (33 of 39 — every `submit_*` and `claim_exit` is refused with 403, because the browser sends through the wallet). `web3Client.ts` gained `callConnector`, `isEnvelope` and `executeEnvelope`, which walks a prepared envelope through the existing `sendOnChainTx` one step at a time, waiting for each. The site and the connector now share one source of truth for quotes, fees and approval copy. 2. **Exit ETAs.** `quote_exit`, `prepare_exit` and `get_exit_status` read `confirmPeriodBlocks` off the rollup and measure the parent's cadence over the last 1000 blocks, rather than hardcoding either. They state the caveat that the window starts at the assertion covering the withdrawal, not at the withdrawal. 3. **NguLauncher** is deployed at `0xEA2cE320B5CDbF14bc734FeB60c78097e146f1B0` (block 35, fanoutSink verified) and set in `l4.nguLauncher`. All nine NGU tools are live against it. Known unrelated breakage: `npm run lint` fails with 11 errors, all in the orphaned `src/components/OrbitL3Explorer.tsx`, which still imports `l3Addresses`, `loadL3Info`, `orbitL3RpcUrl` and `XMONEY_USD_L2` from before the L3→L4 rename. Nothing imports the component. ## The agent wallet (optional, and custodial on purpose) An agent has no browser and no wallet, so `prepare_*` on its own is a dead end for one. Set `PRIVY_APP_ID` and `PRIVY_APP_SECRET` and three more tools appear: - `wallet_status` : the address it signs as, and what it holds on both chains - `wallet_create` : make the wallet once, then fund it - `wallet_execute` : run any `prepare_*` tool and actually send it, with `confirm: true` and an idempotency key Privy signs; this connector broadcasts (Privy's own RPC has never heard of chain 466301). Over stdio there is one caller and it gets one wallet. Over HTTP there are as many callers as there are people signed in, and each gets their own: the X sign-in is the gate, the wallet is filed under that X id, and no tool can reach anyone else's. Signed out, the HTTP surface is reads and prepares only. `MCP_AUTH_TOKEN` is for our own tooling, not for users. | Variable | Use | |---|---| | `PRIVY_APP_ID`, `PRIVY_APP_SECRET` | turn the wallet tools on | | `PRIVY_WALLET_ID`, `PRIVY_WALLET_ADDRESS` | pin a specific wallet instead of the local store | | `MCP_AUTH_TOKEN` | operator token for our own tooling; users use their X sign-in instead | --- _Source: https://npm.io/package/xgas-mcp · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._