Shinjuku Shield MCP
A community MCP server that enables AI agents to make private x402 payments on Solana using a self-custody shielded wallet. It allows agents to shield USDC, pay any x402 endpoint without revealing the payer's identity on-chain, and interact with the Shinjuku Undermarket game. The server handles privacy work off-chain and settles payments instantly, requiring no SOL for fees as the facilitator covers network costs.
Package and access
Local package with source-attributed installation metadata. Koskamo does not execute packages during review.
What you can do with it
- Shield USDC into a private balance for agent payments
- Pay any Solana x402 endpoint privately without exposing wallet address
- Interact with the Shinjuku Undermarket 3D game using AI agents
- Set up self-custody wallet with no RPC keys or API sign-ups
Source and maintenance
- Maintenance checked
Packages and installation
Source-provided package data. Koskamo has not executed or live-probed this package.
shinjuku-shield 0.3.131
{
"version": "0.3.131",
"transport": "stdio",
"identifier": "shinjuku-shield",
"runtimeHint": "npx",
"registryType": "npm",
"registryBaseUrl": "https://registry.npmjs.org",
"packageArguments": [
{
"type": "positional",
"value": "mcp",
"valueHint": "command",
"description": "The wallet command that runs the MCP server on stdio."
},
{
"name": "--max-payment",
"type": "named",
"format": "number",
"description": "The most one payment may cost, in USDC (0.05 = 5 cents). Optional (default: no limit); setup writes the caps you set to config.json.",
"placeholder": "0.05"
},
{
"name": "--max-session",
"type": "named",
"format": "number",
"description": "The most this wallet may pay in any 24 hours, from every MCP process together, in USDC (0.2 = 20 cents). Optional (default: no limit); setup writes the caps you set to config.json.",
"placeholder": "0.2"
},
{
"name": "--pool",
"type": "named",
"default": "CDtxyRjCUs2pu7t3U9TwtpnZwyxBFZ4dKXvb4RCmXHXv",
"description": "The shielded pool. The wallet file is $SHIELDED_WALLET_HOME/<pool>/wallet.json."
},
{
"name": "--program",
"type": "named",
"default": "8PYPw3FSFTMbvSneXdcoH6jNoN4VD23nHwPY2A2riUy1",
"description": "The shielded pool program."
},
{
"name": "--memo-service",
"type": "named",
"default": "https://pay.shinjukustaition.com",
"description": "The facilitator that serves the encrypted memos. Its RPC relay serves reads without --rpc-file."
},
{
"name": "--passphrase-file",
"type": "named",
"format": "filepath",
"description": "Absolute path of a private file that holds the wallet passphrase. Without it, SHIELDED_WALLET_PASSPHRASE."
},
{
"name": "--proof-tools",
"type": "named",
"format": "filepath",
"description": "Absolute path of proof-tools.json. Turns wallet_shield on and is needed to pay shielded-exact."
},
{
"name": "--exit-proof-tools",
"type": "named",
"format": "filepath",
"description": "Absolute path of exit-proof-tools.json. With --profile and --proof-tools, turns wallet_unshield on."
},
{
"name": "--profile",
"type": "named",
"format": "filepath",
"description": "Absolute path of public-profile.json (the facilitator's public profile). Needed for wallet_unshield."
},
{
"name": "--unshield-to",
"type": "named",
"isRepeated": true,
"description": "A public Solana address that wallet_unshield sends to with no confirmation. Never the wallet's own key."
},
{
"name": "--max-unshield",
"type": "named",
"format": "number",
"description": "The most one wallet_unshield call may send, and the most this wallet may send in any 24 hours, in USDC (1 = 1 USDC)."
},
{
"name": "--max-shield",
"type": "named",
"format": "number",
"description": "The most one wallet_shield deposit may move, and the most this wallet may shield in any 24 hours, in USDC (1 = 1 USDC)."
},
{
"name": "--max-per-host-day",
"type": "named",
"format": "number",
"description": "The most one seller host may receive in 24 hours, in USDC."
},
{
"name": "--allow-host",
"type": "named",
"isRepeated": true,
"description": "Pay only this seller host (host or host:port)."
},
{
"name": "--rpc-file",
"type": "named",
"format": "filepath",
"description": "Absolute path of a private file with your own Solana RPC URL. Without it, reads go to the facilitator relay."
},
{
"name": "--no-auto-pockets",
"type": "named",
"description": "Stop the idle return of pockets that an older version filled to the shielded balance. Standard exact sellers are paid through Shinjuku (float pay); no pocket is filled."
}
],
"runtimeArguments": [
{
"name": "--no-audit",
"type": "named",
"description": "npx skips npm's audit request when it installs a new version (that request once held the start for 5 minutes)."
},
{
"name": "--no-fund",
"type": "named",
"description": "npx skips npm's funding message when it installs a new version."
}
],
"environmentVariables": [
{
"name": "SHIELDED_WALLET_HOME",
"format": "filepath",
"description": "The private folder that holds the encrypted wallet and config.json. Default: ~/.carbon-shielded-wallet (the folder that setup uses)."
},
{
"name": "SHIELDED_WALLET_PASSPHRASE",
"description": "The wallet passphrase, if you do not use --passphrase-file."
}
]
}Tools
Reported by the attributed source; not independently observed by Koskamo.
Connect from your client
Each snippet configures the same source-provided package; replace placeholders before use.
Cursor
{
"mcpServers": {
"shinjuku-shield-mcp": {
"command": "npx",
"args": [
"-y",
"shinjuku-shield@0.3.131",
"mcp"
],
"env": {
"SHIELDED_WALLET_HOME": "<YOUR_SHIELDED_WALLET_HOME>",
"SHIELDED_WALLET_PASSPHRASE": "<YOUR_SHIELDED_WALLET_PASSPHRASE>"
}
}
}
}Cline
{
"mcpServers": {
"shinjuku-shield-mcp": {
"command": "npx",
"args": [
"-y",
"shinjuku-shield@0.3.131",
"mcp"
],
"env": {
"SHIELDED_WALLET_HOME": "<YOUR_SHIELDED_WALLET_HOME>",
"SHIELDED_WALLET_PASSPHRASE": "<YOUR_SHIELDED_WALLET_PASSPHRASE>"
}
}
}
}VS Code
{
"servers": {
"shinjuku-shield-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"shinjuku-shield@0.3.131",
"mcp"
],
"env": {
"SHIELDED_WALLET_HOME": "<YOUR_SHIELDED_WALLET_HOME>",
"SHIELDED_WALLET_PASSPHRASE": "<YOUR_SHIELDED_WALLET_PASSPHRASE>"
}
}
}
}Claude Desktop
{
"mcpServers": {
"shinjuku-shield-mcp": {
"command": "npx",
"args": [
"-y",
"shinjuku-shield@0.3.131",
"mcp"
],
"env": {
"SHIELDED_WALLET_HOME": "<YOUR_SHIELDED_WALLET_HOME>",
"SHIELDED_WALLET_PASSPHRASE": "<YOUR_SHIELDED_WALLET_PASSPHRASE>"
}
}
}
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