SSH MCP Server
What Is This?
SSH MCP Server lets you manage remote Linux servers through natural language in VS Code Copilot Chat. Instead of switching to a terminal and remembering SSH commands, you just ask:
"Check disk usage on production-web"
"Show me the last 200 lines of /var/log/nginx/error.log on staging"
"Download /var/log/syslog from web-server-01 for incident INC-2026-0309"
The server enforces strict security policies — no raw shell access, all commands go through pre-approved templates, parameters are regex-validated, secrets in output are auto-redacted, and privileged operations require an approval workflow.
Features
23 MCP tools — host discovery, session management, command execution (sync + background), file transfer, SFTP operations, SSH key management, certificate lifecycle, approval workflows
Template-only execution — no raw shell; every command matches a registered template with regex-validated parameters
3-tier security model — read-only (Tier 0), controlled mutation with confirmation (Tier 1), privileged with approval workflow (Tier 2)
Automatic secret redaction — AWS keys, bearer tokens, passwords, private keys are scrubbed from output
Tamper-evident audit log — every operation is logged with hash-chain integrity verification
Short-lived SSH certificates — issue and revoke certificates with TTL enforcement via a local CA
Persistent SSH sessions — connection pooling with keepalive probes and configurable idle timeout
Background command execution — run long-running template commands asynchronously with output polling
Path traversal protection —
..sequences blocked in all path parameters and file transfersTransfer policy — allowed paths, blocked extensions, size limits, mandatory justification for downloads
Quick Start
Prerequisites
Python 3.11+
VS Code with GitHub Copilot extension
SSH access to at least one remote Linux host
Install
As vscode plugin
Follow instructions on link:
https://marketplace.visualstudio.com/items?itemName=bhayanak.ssh-mcp-server-secure
Python package: https://pypi.org/project/ssh-mcp-server-copilot/
Install from Source (for development / contributing)
git clone https://github.com/bhayanak/ssh-mcp-server.git
cd ssh-mcp-server
python -m venv .venv
source .venv/bin/activate # macOS/Linux
# .venv\Scripts\activate # Windows
pip install -e ".[dev]"For local development, create .vscode/mcp.json pointing to the local source:
{
"servers": {
"ssh-mcp": {
"type": "stdio",
"command": "${workspaceFolder}/.venv/bin/python",
"args": ["-m", "ssh_mcp.server"],
"env": {
"SSH_MCP_CONFIG_DIR": "${workspaceFolder}/config",
"SSH_MCP_HOSTS_FILE": "${workspaceFolder}/config/hosts.json",
"SSH_MCP_TEMPLATES_FILE": "${workspaceFolder}/config/templates.json",
"SSH_MCP_AUDIT_LOG_DIR": "${workspaceFolder}/audit_logs",
"SSH_MCP_CERT_DATA_DIR": "${workspaceFolder}/cert_data",
"SSH_MCP_APPROVAL_DATA_DIR": "${workspaceFolder}/approval_data",
"SSH_MCP_SSH_KNOWN_HOSTS_FILE": "~/.ssh/known_hosts"
}
}
}
}Configure Your Hosts
Edit the hosts file with your actual servers. If you used ssh-mcp-server-copilot init, edit ~/.ssh-mcp/hosts.json. If developing from source, edit config/hosts.json.
[
{
"host_id": "my-server",
"hostname": "192.168.1.10",
"port": 22,
"ssh_user": "deploy",
"labels": {"env": "production", "role": "web"},
"description": "Production web server",
"allowed_roles": ["operator", "admin"]
}
]Field | Required | Description |
| Yes | Unique identifier (alphanumeric, dots, dashes) |
| Yes | IP address or FQDN |
| No | SSH port (default: 22) |
| Yes* | Remote SSH username. If empty, uses your OS username |
| No | Key-value tags for organization |
| No | Human-readable description |
| No | Which roles can access this host (default: operator, admin) |
Set Up SSH Access
Your SSH key must be authorized on each host:
# Generate a key if you don't have one
ssh-keygen -t ed25519 -C "your-email@example.com"
# Copy to each host
ssh-copy-id -i ~/.ssh/id_ed25519.pub deploy@192.168.1.10
# Load into ssh-agent (required — the MCP server uses the agent)
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519
# Verify access
ssh deploy@192.168.1.10 "echo OK"Add host keys to known_hosts:
ssh-keyscan -H 192.168.1.10 >> ~/.ssh/known_hostsStart Using
Open the workspace in VS Code
The MCP server auto-starts from
.vscode/mcp.jsonOpen Copilot Chat (Cmd+Shift+I / Ctrl+Shift+I)
Switch to "Agent" mode (critical — only Agent mode can invoke MCP tools)
Verify tools are loaded — click the tools icon in the chat input bar, you should see 23 tools from
ssh-mcp
Now just ask in natural language:
> List all my SSH hosts
> Check disk usage on my-server
> Show me the last 100 lines of /var/log/syslog on my-server
> What's the status of nginx on my-server?Tools (23)
Tier 0 — Read-Only (No Confirmation)
Tool | Description |
| List all configured SSH hosts with labels and metadata |
| Get OS, uptime, kernel info from a host |
| View the tamper-evident audit trail |
| List available command templates |
| View pending approval requests |
Session Management
Tool | Description |
| Open a persistent SSH session (returns session_id for reuse) |
| Close a persistent session |
| List active sessions and remaining connection slots |
| Health-check a session (liveness, idle time, uptime) |
Tier 1 — Controlled Mutation (Confirmation Required)
Tool | Description |
| Execute a template command on a host (supports |
| Download/upload files via SFTP with path and extension policies (supports |
Background Command Execution
Tool | Description |
| Start a template command in the background (returns job_id) |
| Read accumulated stdout/stderr of a background job (redacted) |
| List all background jobs (running + completed) |
| Cancel a running background job |
Enhanced SFTP
Tool | Description |
| List files in a remote directory (within allowed paths) |
| Delete a remote file (within allowed paths, requires justification) |
Tier 2 — Privileged (Approval Required)
Tool | Description |
| Register a public SSH key with TTL enforcement |
| Revoke a registered SSH key |
| Issue a short-lived SSH certificate via the local CA |
| Revoke a certificate and delete its PEM |
| Approval workflow for privileged ops |
Configuration
Command Templates
Templates define which commands can be executed. Edit config/templates.json:
[
{
"template_id": "disk_usage",
"description": "Show disk usage summary",
"command": "df -h",
"allowed_params": {},
"allowed_roles": ["developer", "operator", "admin"],
"timeout_seconds": 10,
"risk_level": "low"
},
{
"template_id": "tail_log",
"description": "Tail the last N lines of a log file",
"command": "tail -n {lines} {log_path}",
"allowed_params": {
"lines": "^[0-9]{1,5}$",
"log_path": "^/var/log/[a-zA-Z0-9_./-]+$"
},
"allowed_roles": ["operator", "admin"],
"timeout_seconds": 15,
"risk_level": "low"
}
]Each parameter is validated against a regex pattern before substitution. Path traversal (..) is blocked automatically.
Environment Variables
All configuration is via environment variables with the SSH_MCP_ prefix:
Variable | Default | Description |
|
| Base config directory (all other paths derive from this) |
|
| Path to hosts configuration |
|
| Path to command templates |
|
| Audit log directory |
|
| Certificate storage directory |
|
| Approval data directory |
|
| Max simultaneous SSH sessions |
|
| Idle session timeout (seconds) |
|
| SSH keepalive interval (seconds) |
|
| Max failed keepalive probes before disconnect |
|
| Max concurrent background jobs |
|
| Max output buffer per background job (1 MB) |
|
| Background job auto-expiry (1 hour) |
| (none) | Path to SSH known_hosts file |
|
| Require different user as approver |
| (none) | Bearer token (empty = dev mode) |
|
| SSH connection timeout |
Transfer Policy (Defaults)
Setting | Default |
Allowed paths |
|
Blocked extensions |
|
Max file size | 50 MB |
Require justification for downloads | Yes |
Roles
Role | Access |
| Read-only tools, low-risk commands |
| All Tier 0 + Tier 1 tools |
| All tools including Tier 2 (key/cert management) |
| Audit log access |
Security
Design Principles
No raw shell — all commands go through registered templates
Parameter validation — every parameter is regex-validated before substitution
Path traversal blocking —
..sequences rejected in all parameters and file pathsSecret redaction — AWS keys, bearer tokens, passwords, private keys automatically scrubbed from output
Approval workflow — privileged operations (key/cert management) require explicit approval with HMAC-verified tokens
Tamper-evident audit — hash-chained audit log for forensic analysis
Strict host validation — paramiko
RejectPolicyby default (no auto-accepting unknown hosts)TTL enforcement — SSH certificates and keys have configurable maximum lifetimes
Approval Workflow
Tier 2 operations follow a 3-step flow:
1. request_approval → returns request_id + one-time approval_token
2. approve_request → verifies HMAC token, marks approved
3. call the tool → pass approval_request_id, consumed after useWith REQUIRE_TWO_PARTY_APPROVAL=true (production), a different user must approve.
Audit Log Verification
python -c "
from ssh_mcp.audit import AuditLogger
from pathlib import Path
logger = AuditLogger(Path('audit_logs'))
ok, msg = logger.verify_chain()
print(f'Chain integrity: {ok} — {msg}')
"Testing
Unit Tests
# Run all tests
pytest tests/ -v
# With coverage
pytest tests/ -v --cov=ssh_mcpRuntime Directories (git-ignored, auto-created)
Directory | Purpose |
| Tamper-evident audit log ( |
| CA keys, issued certificates, revocation list |
| Pending and consumed approval requests |
CLI Reference
ssh-mcp-server-copilot --version # Print version
ssh-mcp-server-copilot init # Create ~/.ssh-mcp with default configs
ssh-mcp-server-copilot # Start MCP server (stdio transport)
ssh-mcp-server-copilot --config-dir PATH # Use custom config directory
ssh-mcp-server-copilot --config-dir PATH init # Init a custom config directoryContributing
Fork the repository
Create a feature branch:
git checkout -b feature/my-featureMake your changes
Run tests:
pytest tests/ -vLint:
ruff check src/ tests/Submit a pull request