Which integrations are available for this server?

Enables AI agents to interact with the Ethereum network by facilitating secure wallet connections, message signing, and transaction execution through a browser-based approval interface. Enables AI agents to interact with the Optimism network by facilitating secure wallet connections, message signing, and transaction execution through a browser-based approval interface. Enables AI agents to interact with the Polygon network by facilitating secure wallet connections, message signing, and transaction execution through a browser-based approval interface.

MCP Wallet Signer

npm version License: MIT MCP Badge

Your private keys never leave your browser. Every transaction requires explicit user approval in your wallet.

Most blockchain MCPs require you to paste a private key into a config file — giving the AI agent full, unsupervised access to your funds. MCP Wallet Signer takes a different approach: it routes every transaction to your actual browser wallet (MetaMask, Rabby, etc.) via EIP-6963, so you review and approve each action just like any other dapp interaction. No keys in config files, no risk of silent transactions.

Compatible With

Works with any MCP-compatible client via stdio transport.

Installation

Claude Code CLI

claude mcp add evm-wallet -- npx -y mcp-wallet-signer

Claude Desktop

Add to your claude_desktop_config.json:

{ "mcpServers": { "evm-wallet": { "command": "npx", "args": ["-y", "mcp-wallet-signer"] } } }

Run directly

npx -y mcp-wallet-signer pnpx mcp-wallet-signer bunx mcp-wallet-signer

MCP Tools

Tool	Description	Browser Required
`connect_wallet`	Connect wallet, return address	Yes
`send_transaction`	Send ETH/tokens, call contracts	Yes
`sign_message`	Sign arbitrary message (personal_sign)	Yes
`sign_typed_data`	Sign EIP-712 typed data	Yes
`get_balance`	Read ETH balance (via RPC)	No

How It Works

Agent calls an MCP tool (e.g., send_transaction)
Server opens browser to a local signing page
User connects wallet and approves the action
Result (address, tx hash, signature) returned to agent

Supported Chains

Built-in RPC URLs for:

Ethereum (1)
Sepolia (11155111)
Polygon (137)
Arbitrum One (42161)
Optimism (10)
Base (8453)
Avalanche (43114)
BNB Smart Chain (56)

Configuration

Environment variables (optional):

Variable	Description	Default
`EVM_MCP_PORT`	HTTP server port	3847
`EVM_MCP_DEFAULT_CHAIN`	Default chain ID	1

Development

Requires Deno v2.0+.

# Install dependencies deno install cd web && deno install && cd .. # Run MCP server in dev mode deno task dev # Run web UI dev server (separate terminal) deno task dev:web # Run tests deno task test # Build web UI deno task build:web # Build for npm deno task build:npm # Format code deno task fmt # Lint code deno task lint

Project Structure

Developed with Deno, published to npm via dnt. Source in src/ uses node: builtins (no Deno-specific APIs) so the npm bundle runs under Node.js.

deno.jsonc # Deno config + npm package metadata (single source of truth for version) server.json # MCP registry manifest (read by LobeHub etc. from git) scripts/build-npm.ts # dnt build: reads deno.jsonc, transforms src/ → npm/ ├── src/ # Server source (TypeScript, runs under both Deno and Node) │ ├── index.ts # CLI entry point │ ├── mcp-server.ts # MCP tool definitions │ ├── http-server.ts # Lazy-started HTTP server for browser approval UI │ ├── wallet-signer.ts # Core signing orchestration │ ├── pending-store.ts # Promise-based request tracking │ ├── schemas.ts # Zod schemas for MCP tool inputs │ ├── transport.ts # viem custom transport │ ├── viem-account.ts # viem local account adapter │ ├── mod.ts # Library export (npm: "mcp-wallet-signer") │ ├── wallet-only.ts # Library export (npm: "mcp-wallet-signer/wallet-only") │ └── version.ts # Reads version from package.json at runtime ├── web/ # Svelte UI (wallet approval pages) │ └── src/ │ ├── App.svelte │ └── components/ # ConnectWallet, TransactionSigner, MessageSigner ├── tests/ │ ├── *.test.ts # Unit tests │ ├── e2e/ # E2E tests (HTTP API) │ └── e2e-browser/ # E2E tests (Playwright, real browser wallet) └── npm/ # Generated — dnt output + built web assets

Build pipeline

deno task build:npm runs scripts/build-npm.ts which:

Transforms src/ to ESM JavaScript via dnt → npm/esm/
Generates npm/package.json from metadata in deno.jsonc
Builds the Svelte web UI (web/ → web/dist/)
Copies web assets into npm/web/

Dev workflow

deno task dev # Run MCP server directly with Deno deno task dev:web # Vite dev server for web UI (separate terminal) deno task test # Unit + E2E API tests deno task check # Type check + lint + format check

License

MIT

MCP Wallet Signer

MCP Wallet Signer

Compatible With

Installation

Claude Code CLI

Claude Desktop

Run directly

MCP Tools

How It Works

Supported Chains

Configuration

Development

Project Structure

Build pipeline

Dev workflow

License

Resources

Latest Blog Posts

MCP directory API