AI导哈

敏感信息处理CLI与MCP服务器

nfi-tools 是一款用于安全处理敏感信息的命令行工具和 MCP 服务器，可在不向 AI 助手暴露密钥值的前提下，通过浏览器或 TTY 输入密钥并写入 .env、JSON、YAML、TOML 等配置文件，适用于 AI 辅助开发、密钥管理和环境变量配置场景。

  • by bendechrai
  • TypeScript
  • 本地部署
  • 2 星标
  • 更新于
在 GitHub 查看 bendechrai/nfi-tool

使用说明

nfi-tools

CLI tool and MCP server for handling sensitive information without exposing secret values to AI assistants.

When you tell an AI assistant "add my Stripe key to .env", the assistant calls nfi which opens a browser-based prompt for you to enter the secret. The value goes straight into the file -- the AI never sees it.

Install

npm install -g nfi-tools

Or use without installing:

npx nfi-tools set .env STRIPE_SECRET_KEY

How it works

  1. You tell the AI: "Add my Stripe secret key to .env"
  2. The AI runs: nfi set .env STRIPE_SECRET_KEY
  3. A browser tab opens with a password input form
  4. You paste your secret (password managers work here)
  5. The tool writes STRIPE_SECRET_KEY=sk_live_... to .env
  6. The AI only sees: "Wrote 1 secret to .env"

The secret never enters the AI's context window. The browser-based input also means you can paste straight from 1Password, Bitwarden, LastPass, or your browser's built-in password manager. Autofill is deliberately suppressed on the page, since the one-off URL never matches a saved login anyway.

Commands

Set secrets

nfi set .env STRIPE_SECRET_KEY                    # single secret
nfi set .env STRIPE_SECRET_KEY DATABASE_URL       # multiple secrets in one form
nfi set config.json database.password             # nested key in JSON
nfi set config.yaml api.key --overwrite           # overwrite existing

Check if a key exists

nfi has API_KEY .env        # exit code 0 if exists, 1 if not
nfi has API_KEY .env -q     # quiet mode, exit code only

List keys (no values)

nfi keys .env                     # flat list for .env
nfi keys config.json              # leaf paths: database.host, database.port, ...
nfi keys config.json --depth 1    # top-level only: database, api, ...

Diff keys between files

nfi diff .env .env.example        # what's missing from each

Remove a key

nfi remove API_KEY .env           # deletes the line entirely

Copy a secret between files

nfi copy DATABASE_URL .env config.json --path database.url

The value is read and written internally -- it never appears in stdout.

Generate random secrets

nfi generate SESSION_SECRET .env                        # default: hex, 64 chars
nfi generate APP_KEY .env --template uuid               # UUID v4
nfi generate TOKEN .env --template base64:32            # base64, 32 chars
nfi generate SECRET .env --template alphanumeric:48     # alphanumeric, 48 chars
nfi generate KEY .env --dry-run                         # preview without writing

Supported formats

Format Detection Notes
.env .env, .env.local, .env.* Preserves comments and blank lines. Handles export prefix and inline comments.
.json .json Dot notation for nested paths (database.password)
.yaml / .yml .yaml, .yml Dot notation for nested paths
.toml .toml Dot notation for nested paths

Override detection with --format:

nfi set secrets.txt API_KEY --format env

MCP server

For AI clients that support MCP but not shell access (Claude Desktop, Cursor, etc.):

nfi mcp install                    # auto-detect client
nfi mcp install --client cursor    # specify client

This registers nfi as an MCP server. The AI can then call tools like store_secret, check_secret, list_keys, and generate_secret directly.

Available MCP tools:

  • store_secret - prompt for secret(s) via browser, write to file
  • check_secret - check if a key exists (never reveals the value)
  • list_keys - list all key names in a file
  • diff_keys - compare keys between two files
  • generate_secret - generate and write a random secret
  • remove_secret - remove a key from a file
  • copy_secret - copy a secret between files
  • describe_capabilities - list available tools, formats, and templates

Configuration

Optional config file at ~/.config/nfi/config.json:

{
  "timeout": 300000,
  "defaultFormat": null,
  "overwriteByDefault": false,
  "inputMethod": "auto",
  "generateTemplate": "hex:64"
}
  • timeout - browser prompt timeout in ms (default: 5 minutes)
  • inputMethod - "auto" (browser with TTY fallback), "browser", or "tty"
  • generateTemplate - default template for nfi generate

CLI flags always override config values.

Global flags

Flag Description
--format <fmt> Override format detection (env, json, yaml, toml)
--overwrite Allow replacing existing keys
--verbose Show detailed output
--quiet Suppress output (exit code only)
--timeout <ms> Browser prompt timeout
--dry-run Preview without writing (generate only)

Security

  • Secret values never appear in stdout, stderr, or tool return values
  • Browser input collected via a temporary localhost server with a one-time token
  • Token comparisons use constant-time equality to prevent timing attacks
  • POST submissions validated against the Origin header
  • Request body size limited to prevent memory exhaustion
  • TTY fallback reads from /dev/tty directly, bypassing AI-controlled stdin
  • If /dev/tty is unavailable, the tool errors rather than falling back to stdin
  • .gitignore warnings when writing to files not covered by .gitignore

Input fallback chain

  1. Browser - opens a localhost page with password fields (paste from your password manager; autofill is suppressed)
  2. URL relay - if the browser can't auto-open (MCP/remote), returns a clickable URL
  3. TTY - direct /dev/tty prompt with masked input (SSH sessions, headless environments)

Requirements

  • Node.js 20+
  • Also works with Bun

License

MIT

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