MCP Server

MCP Server

zefer-cli doubles as a Model Context Protocol (MCP) server, so AI agents can encrypt, decrypt, generate keys, analyze passwords, and inspect .zefer files directly — everything runs locally over stdio with zero telemetry. Dedicated, copy-ready setup guides per tool live at https://zefer.carrillo.app/mcp.

Start the server

zefer mcp     # explicit

Smart detection: when launched with no arguments and piped stdin (how MCP clients spawn servers), the binary auto-starts in MCP mode; an interactive TTY always gets the regular CLI. It works with the npm install, npx zefer-cli mcp, and the standalone binaries.

Client configuration

// global install
{ "mcpServers": { "zefer": { "command": "zefer", "args": ["mcp"] } } }

// or via npx (no install required)
{ "mcpServers": { "zefer": { "command": "npx", "args": ["-y", "zefer-cli", "mcp"] } } }

Setup guides are provided for Claude Code (incl. claude mcp add), Claude Desktop, Cursor, Windsurf, VS Code (Copilot servers format), Zed (context_servers), and any generic stdio MCP client. Cursor and VS Code also have one-click install deep links on the /mcp page.

Exposed tools

Tool	What it does
zefer_encrypt	Encrypt text or files into .zefer with every option (dual key, reveal key, TTL, secret question, compression, IP allowlist)
zefer_decrypt	Decrypt .zefer files (text returned inline; files written to disk)
zefer_keygen	Generate scored keys — 7 modes plus advanced options, sorted strongest first
zefer_analyze_password	Full strength report: entropy, 4 attack scenarios (10²–10¹⁵ guesses/s), NIST SP 800-63B / OWASP / AES-128 / post-quantum compliance
zefer_inspect	Deep .zefer analysis without the passphrase: structure, entropy, SHA-256, KDF resistance, observations

Example call

{ "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": {
  "name": "zefer_encrypt",
  "arguments": {
    "text": "api_key=abc123",
    "passphrase": "my-strong-pass",
    "outputPath": "secret.zefer",
    "ttlMinutes": 1440,
    "compression": "gzip"
  }
}}

Privacy

The MCP server is stdio-based, dependency-free, and runs entirely locally — no network, no telemetry. Files it produces are the same .zefer format as the web app, CLI, and library, so they interoperate seamlessly.

See also: CLI · Library.

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📖 Glossary — terms on this page: MCP · AES-256-GCM · entropy · post-quantum · zero-knowledge. Full list in the Glossary.