ssh-admin

MCP (Model Context Protocol) server for managing SSH connections to remote servers. Provides host registry, session pool, and secure command execution with read-only protection.

Features

• Server Registry: Add, list, update, delete SSH server configurations with mtime-based caching

• Connection Pool: Automatic session deduplication (max 1 per host), graceful reconnect

• Command Execution: Run shell commands on active SSH sessions with whitelist + write pattern detection

• Raw Command Execute: Unfiltered command execution with changelog logging and user approval

• Readonly Mode: Optional strict read-only mode that blocks all write operations and registry mutations

• Secure Credentials: Passwords stored in environment variables, never in the registry

• Graceful Shutdown: SIGTERM/SIGINT handling with clean session teardown

Related MCP server: MCP SSH Tools Server

Installation

npm install
npm run build

OpenCode Configuration

Example opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "default_agent": "ssh-admin",
  "permission": {},
  "agent": {
    "linuxadmin": {
      "permission": {
        "edit": "deny",
        "bash": "deny",
        "glob": "deny",
        "grep": "deny",
        "list": "deny",
        "read": "deny",
        "task": "deny",
        "external_directory": "deny",
        "todowrite": "allow",
        "question": "allow",
        "webfetch": "deny",
        "websearch": "deny",
        "lsp": "deny",
        "skill": "deny",
        "ssh-admin_*": "ask",
        "ssh-admin_command_execute": "allow",
        "ssh-admin_command_execute_raw": "ask",
        "ssh-admin_registry_list_servers": "allow",
        "ssh-admin_connection_close": "allow",
        "ssh-admin_instruction": "allow",
        "ssh-admin_registry_get_server": "allow",
        "ssh-admin_connection_list": "allow"
      }
    }
  },
  "mcp": {
    "ssh-admin": {
      "type": "local",
      "command": ["node", "./ssh-admin/dist/bundle.cjs"],
      "enabled": true,
      "env": {}
    }
  }
}

Configuration

Adding Servers

Use the registry_add_server tool to add servers:

{
  "name": "registry_add_server",
  "arguments": {
    "alias": "prod-web",
    "host": "192.168.1.100",
    "port": 22,
    "username": "deploy",
    "authMethod": "key",
    "keyPath": "~/.ssh/id_ed25519"
  }
}

For password auth:

{
  "name": "registry_add_server",
  "arguments": {
    "alias": "staging-db",
    "host": "10.0.0.50",
    "port": 2222,
    "username": "admin",
    "authMethod": "password"
  }
}

Then set the password via environment variable:

export SSH_PASSWORD_STAGING_DB="your_password_here"

Running the Server

# Development mode
npm run dev

# Production mode
npm run build && npm start

# Readonly mode (blocks registry writes + all command modifications)
MCP_SSH_READONLY=true npm run dev

MCP Tools

Registry Tools

Connection Tools

Command Tools

Usage Flow

1. instruction                              → get agent instructions
2. registry_list_servers                    → see available hosts
3. connection_open(alias="prod")            → get sessionId
4. command_execute(sessionId, "uptime")     → run first command
5. command_execute(sessionId, "df -h")      → run second command on same session
6. command_execute_raw(sessionId, "systemctl restart nginx") → modify system
7. connection_close(sessionId)              → close session

~/server-info/ Structure

Each server has persistent information stored in its ~/server-info/ directory. These files are updated and read by the AI.

Files

• services.md — Installed services and their status

• packages.md — Installed critical packages

• rules.md — Server constraints and rules

• decisions.md — Decisions made and their rationale

• architecture.md — Architecture notes and configuration details

• changelog.log — Commands executed via command_execute_raw (auto-append)

Directories

• knowledge/ — Knowledge files (.md) created and maintained by the AI

  • Each .md file represents a topic or knowledge domain

  • AI adds or updates files as it learns new server information

• scripts/ — Reusable scripts for frequently performed operations

  • Store automation scripts here to speed up common tasks

  • AI creates and maintains scripts based on recurring operational patterns

Usage Rules

• Read operations: Use command_execute (protected by whitelist + write pattern detection)

• Permanent changes: Use command_execute_raw (unfiltered + user approval required)

  • Read-only commands are blocked in command_execute_raw → use command_execute instead

• Files are updated by AI when system changes occur

• AI reads these files to get server information when needed

Security

Command Protection

Every command goes through a three-layer defense:

1. Whitelist — Unknown commands are blocked (e.g., python, node, perl, ruby, mount, screen, tmux, dd, zip, gzip)

2. Write Argument Detection — Even whitelisted commands are checked for write flags (e.g., tar cf, systemctl restart, docker run, git add)

3. Redirection Detection — File write operators (>, >>) are blocked

No bypass is possible. No permanent modifications can be made through command_execute.

Readonly Mode

When MCP_SSH_READONLY=true:

• Registry write tools (registry_add_server, registry_update_server, registry_delete_server) are disabled

• All commands pass through whitelist + write pattern checks

• No permanent changes can be made to any server

Credentials & Storage

• Passwords are never stored in the registry

• Use environment variables: SSH_PASSWORD_<ALIAS> (uppercase alias)

• Key-based auth is recommended for production use

• Registry directory: ~/.ssh-admin/ with mode 0700

• Registry file: hosts.json with mode 0600

• Password memory is wiped immediately after credential verification

Configuration

Development

npm install          # Install dependencies
npm run dev          # Watch mode via tsx
npm test             # Run tests (477 tests)
npm run build        # TypeScript compile + bundle

License

MIT