Rail runs on your own machine — the client starts it, so there is no endpoint to ping. 17 installs a week from npm. Last commit 29 Sep 2026.
Budgets, propose-then-approve, and receipts for agents that buy for a human. Dry-run by default.
What the code does
We read the source, 5 d ago · rules 995398eba69f
What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.
await fs.unlink(path.join(dir, file));
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
Connect this server
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add rail-mcp -- npx -y rail-mcp{
"mcpServers": {
"rail-mcp": {
"command": "npx",
"args": [
"-y",
"rail-mcp"
]
}
}
}[mcp_servers.rail-mcp]
command = "npx"
args = ["-y", "rail-mcp"]{
"mcpServers": {
"rail-mcp": {
"command": "npx",
"args": [
"-y",
"rail-mcp"
]
}
}
}{
"servers": {
"rail-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"rail-mcp"
]
}
}
}Optional settings from the registry entry, left out of the block above:
RAIL_DATA_DIR (Directory for the local ledger (budget, proposals, receipts). Defaults to ~/.rail in the user home directory. Set to override).
Alternatives to Rail
same job, measured the same waySpending control for AI agents: approved budgets, a decision before each payment, signed receipts.
Wallets, payments and human hiring for AI agents: pay other agents, escrow a budget, hire a person.
Marketplace and payment rail for AI agents: list, buy and settle with signed receipts.
The payment protocol for people and agents. One MCP server, any payment rail.
Paper trading for agent payments: rehearse buying flows, earn policy-bound receipts.
Default trust layer for agentic payments: authorize agent spend, evidence, receipts, settlement.
Personal finance for AI agents: budgets, receipts, net worth, spend checks. Read-only OAuth.
Screen the counterparty of an x402 payment before an agent pays it. Runs offline by default.
Rail — questions
Answers built from our own checks of this server.