Sigil
Let Claude Code sign EVM transactions from a local keystore while the model never reads your private key.
Overview
Sigil is a MCP server for the Ship phase that signs EVM transactions from a local keystore so your agent never sees the private key.
What is this MCP server?
- Local ~/.sigil keystore with optional SIGIL_HOME override for keyfiles, audit log, and control socket
- MCP stdio server (npm sigild 0.0.6 via npx) so agents invoke signing tools without key material in context
- EVM transaction signing workflow where Claude orchestrates signatures but never sees the private key
- Configurable SIGIL_CONTROL_SOCK for daemon control separate from default ~/.sigil/control.sock
- Server schema version 0.0.6
- Single npm package identifier sigild with stdio transport
- Two documented environment overrides: SIGIL_HOME and SIGIL_CONTROL_SOCK
Community signal: 1 GitHub stars.
What problem does it solve?
Letting an LLM draft on-chain actions still forces you to choose between unsafe key exposure and manual copy-paste signing outside the agent loop.
Who is it for?
Solo builders automating EVM workflows in Claude Code who insist on local key custody and MCP-native signing.
Skip if: Teams needing hosted custody, hardware wallets only, or non-EVM chains without additional tooling.
What do I get? / Deliverables
After you register sigild in your MCP config, the agent can request signatures against your local store while keys stay off the model context and on-disk audit paths you control.
- MCP-accessible EVM signing against a local keystore
- On-disk keyfiles and audit trail under your Sigil home
- Agent workflows that never receive raw private key material
Recommended MCP Servers
Journey fit
How it compares
Local signing MCP keystore, not a browser wallet extension or a generic JSON-RPC node.
Common Questions / FAQ
Who is Sigil for?
Indie developers and agent builders who want Claude to drive EVM transactions but keep private keys in a local Sigil store.
When should I use Sigil?
Use it when you are shipping agent-driven on-chain scripts or products and need signing in the MCP loop without ever loading keys into the LLM.
How do I add Sigil to my agent?
Add the stdio MCP entry for npm package sigild (npx), set SIGIL_HOME or SIGIL_CONTROL_SOCK if needed, then restart Claude Code or Cursor so signing tools appear.