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Kastell

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Your infrastructure, fortified.

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★ 58 Stars Category · Dev Tools Popular Source revision 2d77c613f4b6

65FMRS · C

Reliability

8/20

Security and permissions

17/20

Maintenance

13/20

Documentation

14/20

Setup experience

13/20

Kastell is a powerful MCP server for managing self-hosted servers via CLI or AI agents, offering extensive security audits, hardening, and cloud provider integration. It is well-tested (over 11,000 tests) and has a strong focus on security. However, it requires cloud provider API tokens and SSH access. It is best suited for developers and DevOps teams comfortable with Linux server management.

Read the FMRS scoring method →

Kastell is an all-in-one CLI and MCP server for provisioning, securing, backing up, and managing self-hosted servers. It provides comprehensive security audits (449 checks), hardening (24-step), firewall management, auto-fix, monitoring, and supports deployment on Hetzner, DigitalOcean, Vultr, and Linode. It includes a built-in MCP server, allowing AI agents like Claude to manage servers directly.

Tools

server_info

Query server information, check cloud provider and platform status.

server_logs

Fetch platform/Docker logs and system metrics via SSH.

server_manage

server_maintain

Update platform, restart servers, run full maintenance.

server_secure

SSH hardening, firewall rules, domain/SSL management (10 subcommands).

server_backup

Backup/restore databases and create/manage VPS snapshots.

server_provision

Provision new servers on cloud providers.

server_audit

449-check security audit with compliance framework filtering; use --explain for remediation guidance.

server_evidence

Collect forensic evidence package with checksums.

server_guard

Manage autonomous security monitoring daemon.

server_doctor

Proactive health analysis with remediation commands.

server_lock

24-step production hardening (SSH, UFW, sysctl, auditd, AIDE, Docker).

server_fleet

Fleet-wide health and security posture dashboard.

server_fix

Apply safe auto-fixes with backup (SAFE tier only, dryRun default).

Setup

To install the Kastell MCP server:

Ensure Node.js 20 or later is installed.
Add the following configuration to your MCP client config (e.g., .mcp.json for Claude Code, .cursor/mcp.json for Cursor):

{
  "mcpServers": {
    "kastell": {
      "command": "npx",
      "args": ["-y", "-p", "kastell", "kastell-mcp"],
      "env": {
        "HETZNER_TOKEN": "your-token",
        "DIGITALOCEAN_TOKEN": "your-token",
        "VULTR_TOKEN": "your-token",
        "LINODE_TOKEN": "your-token"
      }
    }
  }
}

Optionally, set provider API tokens in environment variables. Certain operations (like provision, destroy, restore) are blocked by default in safe mode; set KASTELL_SAFE_MODE=false to enable them.

claude_desktop_config.json

{
  "mcpServers": {
    "kastell": {
      "command": "npx",
      "args": [
        "-y",
        "-p",
        "kastell",
        "kastell-mcp"
      ],
      "env": {
        "HETZNER_TOKEN": "your-token",
        "DIGITALOCEAN_TOKEN": "your-token",
        "VULTR_TOKEN": "your-token",
        "LINODE_TOKEN": "your-token"
      }
    }
  }
}

Generate and validate client config

Fit and risk

Best for

Developers and DevOps teams looking to manage self-hosted infrastructure via CLI or AI agents
Users who want to streamline server provisioning and hardening across multiple cloud providers
Teams that want to integrate security audits into CI/CD pipelines

Not for

People without SSH access or who do not need cloud provider integrations
Users who require a GUI or managed service rather than a CLI
Those who need macOS/BSD support (Linux only platform)
Those who need full Windows native support (manages Linux servers only via SSH)

Required permissions

Requires access to cloud provider API tokens (Hetzner, DigitalOcean, Vultr, Linode)
Requires SSH access to target servers to perform audits, hardening, and maintenance
Can create SSH keys and configuration files on the local machine
Can execute destructive operations on servers (if enabled)

Risks and side effects

Destructive operations (destroy, restore, snapshot-delete, provision, restart, maintain, snapshot-create) are blocked in default safe mode; if enabled, risk of data loss
API tokens are sensitive; ensure they are stored securely
SSH connections may be intercepted; use strict host key verification
Automated operations may inadvertently change server configurations
Misuse could lead to service disruption or security vulnerabilities

Troubleshooting

If server creation fails, run `kastell doctor --check-tokens` to verify API tokens and environment
If server is unresponsive, try `kastell status my-server --autostart` or `kastell health`
If commands fail on a server, check SSH credentials and host keys
Ensure correct API tokens are set for the desired provider
Check KASTELL_SAFE_MODE setting to ensure destructive operations are allowed or blocked as expected

Use cases

Provision and deploy new servers on cloud providers

Perform full security audits and hardening on existing servers

Backup and restore databases and configurations

Manage fleets of servers and run maintenance

Automate server management via AI agents

Supported clients

Claude CodeFull support

CursorFull support

WindsurfFull support

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