SaturnZap — Claude Code MCP server: what it does, how to install
A non-custodial Lightning wallet for AI agents that pays Bitcoin invoices and L402 APIs through the CLI or MCP.
claude mcp add --env SZ_PASSPHRASE=<SZ_PASSPHRASE> --env SZ_MCP_MAX_SPEND_SATS=<SZ_MCP_MAX_SPEND_SATS> --transport stdio saturnzap -- uvx saturnzapWhat SaturnZap does
SaturnZap runs a Lightning node on the agent’s machine and keeps an encrypted BIP39 seed locally. A full Bitcoin node is not needed: chain data comes through the Esplora REST API with fallback sources. The wallet is non-custodial, so private keys stay under the agent’s control.
You can use the sz CLI, which writes structured JSON, or connect the built-in MCP server over stdio. The MCP layer exposes 25 tools for sending and receiving Bitcoin payments and paying L402-gated APIs. Set SZ_PASSPHRASE in the configuration; SZ_MCP_MAX_SPEND_SATS sets the MCP spending limit.
LQWD is the default Lightning Service Provider, while channels can be opened to any Lightning node. Mainnet spending asks for confirmation unless --yes is supplied, so unattended payment flows need that behaviour configured explicitly.
What it helps with
- pay a Lightning invoice
- fetch data from an L402 API
- connect an AI agent to MCP tools
- receive Bitcoin payments through a local node
Example prompts for the agent
- Pay the Lightning invoice
lnbc1...and keep the amount below 500 sats. - Fetch
https://api.example.com/datathrough L402 and cap the payment at 500 sats. - Check the wallet state and available SaturnZap actions.
How to install SaturnZap
Platform CLI
claude mcp add --env SZ_PASSPHRASE=<SZ_PASSPHRASE> --env SZ_MCP_MAX_SPEND_SATS=<SZ_MCP_MAX_SPEND_SATS> --transport stdio saturnzap -- uvx saturnzapReplace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from saturnzap <command>
Platform CLI
codex mcp add saturnzap --env SZ_PASSPHRASE=<SZ_PASSPHRASE> --env SZ_MCP_MAX_SPEND_SATS=<SZ_MCP_MAX_SPEND_SATS> -- uvx saturnzapReplace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from saturnzap <command>
Config file
{
"mcpServers": {
"saturnzap": {
"command": "uvx",
"args": [
"saturnzap"
],
"env": {
"SZ_PASSPHRASE": "<SZ_PASSPHRASE>",
"SZ_MCP_MAX_SPEND_SATS": "<SZ_MCP_MAX_SPEND_SATS>"
}
}
}
}Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from saturnzap <command>
Config file
{
"servers": {
"saturnzap": {
"type": "stdio",
"command": "uvx",
"args": [
"saturnzap"
],
"env": {
"SZ_PASSPHRASE": "<SZ_PASSPHRASE>",
"SZ_MCP_MAX_SPEND_SATS": "<SZ_MCP_MAX_SPEND_SATS>"
}
}
}
}Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from saturnzap <command>
Platform CLI
gemini mcp add -e SZ_PASSPHRASE=<SZ_PASSPHRASE> -e SZ_MCP_MAX_SPEND_SATS=<SZ_MCP_MAX_SPEND_SATS> saturnzap uvx saturnzapReplace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from saturnzap <command>
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about SaturnZap
How do I install SaturnZap in Claude Code?
Run claude mcp add saturnzap -e SZ_PASSPHRASE=<SZ_PASSPHRASE> -- uvx saturnzap.
What does SaturnZap do?
It gives an AI agent a non-custodial Lightning wallet through a CLI and MCP server. The agent can send or receive Bitcoin payments and pay L402 APIs.
Does SaturnZap require a full Bitcoin node?
No. It reads chain data through the Esplora REST API and does not require bitcoind.
