How do I install MCP Signer?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does MCP Signer need an API key?

No required environment variable is listed on this record.

What transport does MCP Signer use?

MCP Signer runs locally over stdio.

When was MCP Signer last checked?

Last checked 2026-11-09. Local transaction signing for EVM, UTXO, Tron, XRP, Kaspa, Solana and Tezos — no API calls

MCP Signer MCP server

Power your agent

Add this server

The publisher's own command. Not a PlugMCP endpoint.

Add to Cursor Add to VS Code Run on PlugMCP

Host a copy with our keys and logs.

Local command

npx -y @cryptoapis-io/[email protected]

Claude Code has no install link for a local command. Copy the command below and run it in a terminal.

shClaude Code

1claude mcp add io.github.cryptoapis-io-mcp-signer -- npx -y @cryptoapis-io/mcp-signer@0.5.0

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "io.github.cryptoapis-io-mcp-signer": {4      "command": "npx",5      "args": [6        "-y",7        "@cryptoapis-io/[email protected]"8      ]9    }10  }11}

claude_desktop_config.json

Local · npmPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Run on PlugMCP

Host a copy with our keys and logs.

A new server you create. It is not this listing's official endpoint. Use the publisher install when you want their URL and their credentials.

Launch

Server facts

Local

Transport: stdio
Version: 0.5.0
Last checked

Tools

No tool list yet. Remote servers get one after the first health check.

FAQ

Questions

@cryptoapis-io/mcp-signer

MCP server for local transaction signing across EVM, UTXO, Tron, XRP, Kaspa, Solana and Tezos. No Crypto APIs HTTP calls — signing happens entirely on your machine. No API key required.

Security

Stdio only — no HTTP transport. The server does not listen on any port.
Private keys in tool input — each tool receives privateKey / privateKeys / secret as parameters. Keys are never read from environment variables.
No network calls — all signing is done locally using cryptographic libraries.

Installation

npm install @cryptoapis-io/mcp-signer

Or install all Crypto APIs MCP servers: npm install @cryptoapis-io/mcp

Usage

npx @cryptoapis-io/mcp-signer

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "cryptoapis-signer": {
      "command": "npx",
      "args": ["-y", "@cryptoapis-io/mcp-signer"]
    }
  }
}

Cursor

Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "cryptoapis-signer": {
      "command": "npx",
      "args": ["-y", "@cryptoapis-io/mcp-signer"]
    }
  }
}

MCP Inspector

npx @modelcontextprotocol/inspector npx @cryptoapis-io/mcp-signer

Available Tools

`evm_sign`

Sign an EVM transaction (Ethereum, Ethereum Classic, BSC, Polygon, Avalanche (C-Chain), Arbitrum, Base, Optimism, Tron).

Action	Description
`sign-from-details`	Sign from structured transaction fields (to, value, gasLimit, etc.)
`sign-unsigned-hex`	Sign a pre-built unsigned transaction hex
`sign-typed-data`	Sign an EIP-712 typed-data message (the x402 gasless path — e.g. the EIP-3009 `TransferWithAuthorization` from the x402 buyer `/authorize`). Returns `{ signature }`, not a tx.

`utxo_sign`

Sign a UTXO transaction (Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Dash, Zcash).

Action	Description
`sign-from-details`	Sign from a prepared transaction object (inputs, outputs)
`sign-unsigned-hex`	Sign a raw unsigned transaction hex with input descriptors

`tron_sign`

Sign a Tron transaction using secp256k1 (no TronWeb dependency).

Action	Description
`sign-from-details`	Sign from a transaction object with `raw_data_hex`
`sign-unsigned-hex`	Sign a pre-built unsigned transaction hex

`xrp_sign`

Sign an XRP transaction.

Action	Description
`sign-from-details`	Sign from structured XRP transaction fields
`sign-unsigned-hex`	Sign a pre-built unsigned transaction hex

`kaspa_sign`

Sign a Kaspa transaction using schnorr (BIP340) via kaspa-wasm. Mainnet only.

Action	Description
`sign-from-details`	Sign a prepared Kaspa transaction (from the prepare-transaction API)

`svm_sign`

Partial-sign a Solana (SVM) x402 payment transaction — the buyer's source-authority signature only (the facilitator's feePayer slot stays unsigned, signed at settle).

Action	Description
`partial-sign`	Deserialize the base64 unsigned TransferChecked tx from the x402 buyer `/authorize` (scheme `svm-transaction`), add the buyer signature, re-serialize to base64. Returns `{ transaction }`.

`tezos_sign`

Sign a Tezos operation for tz1 (ed25519), tz2 (secp256k1) or tz3 (P-256) keys (edsk… / spsk… / p2sk…).

Action	Description
`sign-forged-operation`	Sign the `forgedOperation` hex from `prepare_transactions_tezos`. The operation is decoded first: only reveal/transaction ops from the key's own address are signed, and the optional `expected` (`destination`, `amount` in mutez, `maxFee`) must match. Returns `{ signedOperation, operationHash, signature, … }`; broadcast `signedOperation`.

Most tools return signedTransactionHex — ready to broadcast with @cryptoapis-io/mcp-broadcast. The x402 paths return { signature } (EVM typed-data) or { transaction } (SVM) instead.

Dependencies

Package	Purpose
`ethers`	EVM transaction signing
`bitcoinjs-lib` + `ecpair` + `tiny-secp256k1`	UTXO transaction signing
`elliptic`	Tron transaction signing (secp256k1)
`xrpl`	XRP transaction signing

License

MIT

Add this server

Host a copy with our keys and logs.

Server facts

Tools

Questions

How do I install MCP Signer?

Does MCP Signer need an API key?

What transport does MCP Signer use?

When was MCP Signer last checked?

Documentation

@cryptoapis-io/mcp-signer

Security

Installation

Usage

Claude Desktop

Cursor

MCP Inspector

Available Tools

evm_sign

utxo_sign

tron_sign

xrp_sign

kaspa_sign

svm_sign

tezos_sign

Dependencies

License

`evm_sign`

`utxo_sign`

`tron_sign`

`xrp_sign`

`kaspa_sign`

`svm_sign`

`tezos_sign`