@0x402/config

~/.acu/config.json — the one place a key and its settings are read from, for every shell.

npm i @0x402/config

import { readUserConfig, writeUserConfig, configPath, resolve } from "@0x402/config";

const user = readUserConfig();
const auditorUrl = resolve(process.env.ACU_AUDITOR_URL, user.auditorUrl, DEFAULT);

Precedence is env > file > built-in default, everywhere, through resolve. An operator can always override the file for one process without editing it, and an empty environment variable counts as unset rather than as an empty string.

This is what makes claude mcp add acu -- npx -y @0x402/mcp need no environment variables: @0x402/cli's init writes the key, and the MCP server reads the same file. MCP configuration is fixed at install time, so a key that arrived later used to mean removing and re-adding the server.

Two properties it holds on to

The file holds a private key, so it is written 0600 inside a 0700 directory, and written atomically via tmp + rename — a half-written config would be a lost key. Writes merge, so one command adding an auditor URL cannot erase another's key, and fields this version has never heard of are carried through untouched.

Absence is not a failure; corruption is. No file means "you have not run init yet" and every field comes back null. A file that exists and will not parse throws, because reading a damaged config as "no key" would send someone to generate a second key over the top of a funded one.

Depends on node builtins and nothing else, so importing it can never drag a parser or a network client into a shell that only wanted to know its key.

Repository · Site · MIT