Mcp Signer
Sign prepared transactions locally in the agent loop on EVM, UTXO, Tron, and XRP without sending keys to a cloud API.
Overview
mcp-signer is a Ship-phase MCP server that performs local transaction signing on EVM, UTXO, Tron, and XRP without remote API calls.
What is this MCP server?
- Local transaction signing for EVM, UTXO, Tron, and XRP with no outbound API calls
- npm package @cryptoapis-io/mcp-signer v0.3.0 over stdio MCP
- No CRYPTOAPIS_API_KEY required in server.json—runs fully offline for signing
- Completes the CryptoAPIs flow after mcp-prepare-transactions or manual unsigned payloads
- Keeps signing operations agent-scriptable while you retain custody of keys
- Server version 0.3.0
- Chain families: EVM, UTXO, Tron, XRP (4)
What problem does it solve?
Pushing signing into cloud APIs or ad-hoc scripts risks key leakage when you already have unsigned txs ready to finalize.
Who is it for?
Builders who prepare txs via agents but insist on local-only signing across EVM, UTXO, Tron, or XRP.
Skip if: Workflows that only need read-only chain data, or teams uncomfortable giving an agent access to signing material on disk.
What do I get? / Deliverables
You get signed transactions from local keys so only broadcast and monitoring steps touch the network.
- Signed transactions ready for broadcast
- Agent-invokable signing across four chain families
- Offline signing path with no Crypto APIs key required for the server itself
Recommended MCP Servers
Journey fit
How it compares
Local-signing MCP tool, not a hosted custodial wallet or transaction simulation service.
Common Questions / FAQ
Who is mcp-signer for?
It is for developers who want agent-assisted signing on EVM, UTXO, Tron, and XRP while keeping private keys off third-party APIs.
When should I use mcp-signer?
Use it in ship after you have an unsigned transaction and acceptable simulation results, immediately before broadcast.
How do I add mcp-signer to my agent?
Install @cryptoapis-io/mcp-signer, register the stdio MCP server, configure local key access per your security model, and call signing tools from your agent.