Fuse MCP Server

Model Context Protocol server for the Fuse blockchain. Lets AI agents (Claude, Cursor, Gemini, ...) read Fuse on-chain data, submit account-abstracted transactions, deploy contracts, and operate Fusebox APIs through one standard tool interface. Two ways to use it: 1. Hosted at https://mcp.fuse.io/mcp — free, read-only, configured with Fuse's API keys. No setup beyond pointing your agent at the URL. 2. Self-hosted via Docker or node dist/index.js — required for any write tool (you must control the private key) and for higher rate limits. Three back-ends, layered: - viem JSON-RPC — chain primitives any public node can serve, plus EOA writes (send FUSE, ERC-20 transfers, generic contract calls, contract deployment, EIP-191 / EIP-712 signing). - Fusebox Web SDK — value-added read APIs (token prices, staking, portfolio, UserOp history) and ERC-4337 smart-account writes via UserOperations (optionally gasless via the Fuse paymaster). - Fusebox REST APIs — direct access to Notification, Smart Wallet, Trade, and Explorer endpoints. ---

Quick install for AI agents (hosted at mcp.fuse.io)

The hosted endpoint speaks the Streamable HTTP transport at https://mcp.fuse.io/mcp. All read tools are enabled; write tools are not (they need a server-side private key — see Self-hosting for writes below).

Claude Code

``bash claude mcp add fuse --transport http https://mcp.fuse.io/mcp ` To remove later: claude mcp remove fuse.

Cursor

Settings → MCP → Add new server, or edit ~/.cursor/mcp.json: `json { "mcpServers": { "fuse": { "url": "https://mcp.fuse.io/mcp" } } } `

Claude Desktop

Claude Desktop currently launches MCP servers as local subprocesses, so it talks to the hosted endpoint through the mcp-remote bridge. Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows): `json { "mcpServers": { "fuse": { "command": "npx", "args": ["-y", "mcp-remote", "https://mcp.fuse.io/mcp"] } } } ` Restart Claude Desktop.

Continue (VS Code / JetBrains)

~/.continue/config.yaml: `yaml mcpServers: - name: fuse url: https://mcp.fuse.io/mcp `

Cline / Roo Code

Add via the MCP sidebar → "Add Remote Server", URL https://mcp.fuse.io/mcp. Or edit ~/.cline/mcp_settings.json: `json { "mcpServers": { "fuse": { "url": "https://mcp.fuse.io/mcp", "transport": "streamable-http" } } } `

Zed

~/.config/zed/settings.json: `json { "context_servers": { "fuse": { "command": { "path": "npx", "args": ["-y", "mcp-remote", "https://mcp.fuse.io/mcp"] } } } } `

Anything else (generic Streamable HTTP client)

Endpoint: https://mcp.fuse.io/mcp Transport: Streamable HTTP (POST + optional SSE upgrade) Auth: none on the hosted endpoint (it's read-only) ---

Self-hosting for writes

The hosted endpoint deliberately runs without FUSE_PRIVATE_KEY — write tools refuse to operate. Run your own instance when you need to sign transactions, deploy contracts, or submit ERC-4337 UserOps.

Docker

`bash docker build -t fuse-mcp-server . docker run --rm -p 3000:3000 \ -e MCP_TRANSPORT=http \ -e FUSEBOX_PUBLIC_API_KEY=pk_live_... \ -e FUSE_PRIVATE_KEY=0x... \ -e FUSE_USE_PAYMASTER=true \ fuse-mcp-server ` Point your agent at http://127.0.0.1:3000/mcp. Same configs as above, swapping the URL.

docker-compose

Drop secrets into a .env file next to docker-compose.yml: `env FUSEBOX_PUBLIC_API_KEY=pk_live_... FUSEBOX_SECRET_API_KEY=sk_live_... FUSE_PRIVATE_KEY=0x... FUSE_USE_PAYMASTER=true ` Then: `bash docker compose up -d `

Node directly (stdio mode for local subprocess clients)

`bash npm install npm run build FUSE_PRIVATE_KEY=0x... node dist/index.js ` For Claude Desktop / any client that spawns the server as a subprocess: `json { "mcpServers": { "fuse": { "command": "node", "args": ["/absolute/path/to/fuse-mcp-server/dist/index.js"], "env": { "FUSEBOX_PUBLIC_API_KEY": "pk_live_...", "FUSE_PRIVATE_KEY": "0x...", "FUSE_USE_PAYMASTER": "true" } } } } ` ---

Tools (v0.2) — 50 total

RPC reads — 8 _(no API key required)_

| Tool | Description | | --- | --- | | fuse_get_balance | Native FUSE or ERC-20 balance. | | fuse_get_transaction | Fetch a transaction. | | fuse_get_receipt | Fetch a transaction receipt. | | fuse_read_contract | Call any view/pure function (ABI auto-fetched). | | fuse_get_token_metadata | name / symbol / decimals / totalSupply. | | fuse_get_gas_price | Current gas price + EIP-1559 fee suggestions. | | fuse_resolve_ens | Resolve an ENS name (requires ENS_RPC_URL). | | fuse_get_account_abstraction_info | ERC-4337 state for a smart account. |

Fusebox SDK reads — 10 _(requires FUSEBOX_PUBLIC_API_KEY)_

fuse_list_wallet_tokens, fuse_list_wallet_nfts, fuse_get_staking_options, fuse_get_staked_tokens, fuse_get_token_price, fuse_get_token_price_change, fuse_get_token_price_history, fuse_list_supported_tokens, fuse_get_trade_quote, fuse_get_user_operations.

Fusebox REST APIs — 14 _(requires FUSEBOX_PUBLIC_API_KEY; Notification also needs FUSEBOX_SECRET_API_KEY)_

Notification (8): fuse_notification_{create,get,list_project,update,delete}_webhook, fuse_notification_{add,remove,list}_addresses. Smart Wallet (2): fuse_smart_wallet_authenticate, fuse_smart_wallet_get_actions. Trade (3, non-SDK): fuse_trade_indicative_price, fuse_trade_liquidity_sources, fuse_trade_price_change_over_duration. Explorer (1 generic dispatcher): fuse_explorer_query — covers all 40+ etherscan-style endpoints.

EOA writes — 7 _(requires FUSE_PRIVATE_KEY)_

| Tool | Description | | --- | --- | | fuse_get_signer_address | Show which EOA the server controls. | | fuse_send_native | Transfer native FUSE. | | fuse_send_erc20 | Transfer an ERC-20 (decimals auto-detected). | | fuse_write_contract | State-mutating call (simulates first to surface revert reasons). | | fuse_deploy_contract | Deploy from bytecode + ABI + args. Optionally waits for the receipt. | | fuse_sign_message | EIP-191 (personal_sign) signature. No tx broadcast. | | fuse_sign_typed_data | EIP-712 structured-data signature. No tx broadcast. |

Smart-account writes (ERC-4337 UserOps) — 11 _(requires FUSE_PRIVATE_KEY + FUSEBOX_PUBLIC_API_KEY)_

fuse_smart_get_info, fuse_smart_transfer_{token,nft}, fuse_smart_approve_{token,nft}, fuse_smart_approve_and_call, fuse_smart_call_contract, fuse_smart_execute_batch, fuse_smart_swap_tokens, fuse_smart_stake_token, fuse_smart_unstake_token. Set FUSE_USE_PAYMASTER=true to route through the Fuse paymaster (gasless). ---

Configuration

| Variable | Default | Purpose | | --- | --- | --- | | MCP_TRANSPORT | stdio | stdio (local subprocess) or http (Streamable HTTP for hosted/Docker). | | MCP_HTTP_HOST | 0.0.0.0 | HTTP bind host. | | MCP_HTTP_PORT | 3000 | HTTP listen port. | | MCP_HTTP_PATH | /mcp | HTTP route path. | | FUSE_NETWORK | mainnet | mainnet (chain 122) or spark (testnet, chain 123). | | FUSE_RPC_URL | network default | Override the JSON-RPC endpoint. | | FUSE_EXPLORER_URL | network default | Override the Blockscout explorer base URL. | | FUSE_ENTRYPOINT_ADDRESS | ERC-4337 v0.7 canonical | Override the EntryPoint. | | ENS_RPC_URL | _unset_ | Ethereum mainnet RPC for .eth resolution. | | FUSEBOX_PUBLIC_API_KEY | _unset_ | Public API key — required for SDK + REST + smart-account tools. | | FUSEBOX_SECRET_API_KEY | _unset_ | Secret API key (API-SECRET header). Required only by Notification API tools. | | FUSEBOX_BASE_URL | SDK default | Override the SDK's Fusebox API host. | | FUSEBOX_API_ORIGIN | https://api.fuse.io | Override the raw HTTP client's Fusebox API origin. | | FUSE_PRIVATE_KEY | _unset_ | 32-byte hex private key for the signer. Required by every write tool. Read once at startup; never accepted as a tool argument. | | FUSE_USE_PAYMASTER | false | When true, smart-account UserOps route through the Fuse paymaster (gasless). |

Security model

- Key handling. Private keys live in the server's environment only. They are never accepted as tool arguments — that would leak them into the agent's conversation transcript. The server reads FUSE_PRIVATE_KEY once at startup and signs locally. - Hosted endpoint. https://mcp.fuse.io/mcp has no FUSE_PRIVATE_KEY configured. Write tools return an actionable error pointing users to self-hosting. The Fusebox public key bundled there is rate-limited for fair sharing. - Self-hosted production. Treat the server as a hot-wallet signer. Run it next to your application, lock down ingress, fund the EOA with the minimum FUSE you're willing to lose to a prompt-injection mishap, and prefer the paymaster (FUSE_USE_PAYMASTER=true) so the smart wallet can transact without holding gas. ---

Project layout

` . ├── Dockerfile Multi-stage build → distroless-ish Alpine runtime, non-root user ├── docker-compose.yml One-line local deploy ├── .dockerignore ├── package.json ├── tsconfig.json └── src/ ├── index.ts Transport dispatcher (stdio | http) ├── server.ts Builds the McpServer + ToolContext ├── config.ts Env loading ├── types.ts Shared tool types ├── transports/ │ ├── stdio.ts Local subprocess transport │ └── http.ts Streamable HTTP transport + /healthz ├── clients/ │ ├── rpc.ts viem PublicClient factories │ ├── signer.ts EOA signer (viem WalletClient + ethers v5 Wallet) │ ├── explorer.ts Blockscout ABI fetcher │ ├── fusebox.ts Fusebox SDK factories (read-only + credentialed) │ └── fuseboxApi.ts Raw HTTP client for Fusebox REST APIs ├── lib/ │ ├── address.ts Address validation, ENS heuristics, hex bytes │ ├── erc20.ts ERC-20 ABI (read + write) │ ├── units.ts parseAmount / fetchErc20Decimals │ ├── format.ts BigInt-safe JSON serialization │ └── userOp.ts UserOp response → JSON-safe summary └── tools/ ├── index.ts Registry (50 tools) ├── *.ts RPC reads (8) ├── listWalletTokens.ts … getUserOperations.ts Fusebox SDK reads (10) ├── notifications/ Fusebox Notification API (8) ├── smartWallets/ Fusebox Smart Wallet API (2) ├── tradeApi/ Fusebox Trade API non-SDK endpoints (3) ├── explorerApi/ Fusebox Explorer API dispatcher (1) ├── writes/ EOA writes (7) └── smart/ Smart-account writes (11) ``