Jacobian runs on your own machine — the client starts it, so there is no endpoint to ping. 249 installs a week from npm. Last commit 29 Oct 2026.
Executable mathematics and independent verification for AI agents.
We read the source, 4 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.
const child = spawn(
Found in continuous integration, deployment or infrastructure files, or in a neighbouring package of the same monorepo. None of this is installed when you add the server: it describes how the project is built and released. We list it because a leaked key in a build pipeline is still a real problem, but it is not something this server does on your machine.
subprocess.run(
environment=dict(os.environ),
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
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.
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 jacobian -- npx -y jacobian
{
"mcpServers": {
"jacobian": {
"command": "npx",
"args": [
"-y",
"jacobian"
]
}
}
}
[mcp_servers.jacobian]
command = "npx"
args = ["-y", "jacobian"]
{
"mcpServers": {
"jacobian": {
"command": "npx",
"args": [
"-y",
"jacobian"
]
}
}
}
{
"servers": {
"jacobian": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"jacobian"
]
}
}
}
Manual-review external execution in Japan for AI agents: human tasks, logistics, and verification.
Bounded authorization and independently verifiable execution evidence for agents.
Disposable email inboxes for AI agents — read messages and verification codes.
Independent effect verification and signed receipts for consequential AI agent actions.
Real email and SMS for AI agents — send mail, receive verification codes, drive a real inbox.
Independent static verification for exact immutable public GitHub commits.
Disposable inboxes for AI agents and CI: catch the verification email, read the OTP or link.
Disposable email inboxes for AI agents: create, wait for mail, extract verification codes
Answers built from our own checks of this server.