
Sigil
Solves the problem of letting Claude sign EVM transactions without exposing your private key in the context window. Keys stay encrypted on disk with XChaCha20-Poly1305, and the MCP server boots locked until you unlock it from a separate terminal via a Unix socket. Once unlocked, Claude can sign EIP-191 personal messages, EIP-1559 and legacy transactions, and EIP-712 typed data through opaque handles like `evm:executor`. Each portal gets a TOML policy file where you can set chain ID restrictions, destination allowlists, per-transaction value caps, and function selector filters. Pre and post hooks block reads of common key paths and redact key-shaped strings from tool output. Still pre-alpha and missing rolling window caps and out-of-band confirmation, so don't use it with real funds yet.
- GitHub stars
- 1
- tool
- 1
- transport
- STDIO
- env vars
- 2
- last updated
- May 20, 2026
Tools
1 toolsPublic tool metadata for what this MCP can expose to an agent.
sigil_eth_sign_transactionWhen the proxy is enabled, sigil-mcp advertises the endpoint, including the authenticated URL, in the sigil_eth_sign_transaction tool description.
When the proxy is enabled, sigil-mcp advertises the endpoint, including the authenticated URL, in the sigil_eth_sign_transaction tool description.
No parameter schema in public metadata yet.
Sponsors
Configuration
SIGIL_HOMEOverride the default ~/.sigil directory for keyfiles, audit log, and control socket.
SIGIL_CONTROL_SOCKOverride the default control socket path (~/.sigil/control.sock).
Readme
sigil
Claude can sign, but never see.
sigil is a local signing tool and Claude Code integration that lets agentic coding tools use private keys without ever putting key material in the model's context window.
Status: pre-alpha. The MCP server, CLI, unlock flow, ward hooks, policy engine (static checks), out-of-band confirmation via ntfy, Solana signing, and the JSON-RPC signing proxy (Foundry/Hardhat) all work end-to-end. Rolling-window value caps and EIP-712 domain allowlists landed in the policy engine, but have not been through a release yet. Until v0.1.0 ships — with the supply-chain attestations promised for it — do not use this with real funds yet. Build plan lives in the tracking issue.
What it is
One MCP server process, four bins (plus a legacy sigild alias), six runtime deps (all pinned, zero transitive):
Details
- Repository
- github.com/cdrn/sigil
- Package
sigild- Transport
- STDIO
- Registry
- MCP registry, active