SSH MCP

Manage persistent SSH connections, execute async non-blocking commands, handle concurrent bulk executions across fleets, and manage SSH keys and client assignments.

SSH Connection & Execution Management Skill

[!IMPORTANT] Dependency Warning: This skill requires the ssh_mcp server to be running and registered with the Model Context Protocol (MCP) host. It enables secure, persistent, non-blocking execution across remote Linux servers.

This skill equips the agent to manage remote SSH connection lifecycles, perform system updates, troubleshoot connectivity, and execute commands in bulk across server fleets.

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Guidelines for the Agent

1. Connection Discovery & Diagnostics

• Use ssh_conn (action list) to view all saved connection configurations.
• Use ssh_conn (action test) to check remote host reachability before saving a new target connection.
• Use ssh_conn (action save) to store connections in the SQLite database to avoid hardcoding auth credentials or private keys in scripts.

2. Session Lifecycle Management

• To run commands, first call ssh_exec (action open) with the target connection ID. This establishes a persistent SSH connection and returns a sessionId.
• Re-use active sessions across multiple command runs instead of repeatedly opening new connections. Monitor active sessions using ssh_exec (action list).
• Always finalize your work by calling ssh_exec (action close) with the sessionId to release resources and prevent orphan connections on remote hosts.

3. Non-Blocking Execution Protocol

• Execute commands using ssh_exec (action run) on an open sessionId. This returns a commandId immediately and does not block the agent's execution.
• Monitor the execution state using ssh_exec (action status) with the commandId.
• Retrieve command output logs using ssh_exec (action logs). Since remote commands can produce long outputs, always use appropriate log filters:
  • grep: Filter output lines matching a regex or substring.
  • head / tail: Limit the number of lines returned.
  • fromLine / toLine: Fetch specific line ranges.
  • stream: Target stdout, stderr, or both.

4. Asynchronous Bulk Execution

• When executing the same command across a client's server fleet, use ssh_bulk_exec or ssh_bulk_audit instead of sequentially looping.
• Dynamic Session Reuse & Auto-Cleanup:
  • If a connection already has an active session, ssh_bulk_exec will automatically reuse it.
  • If no session exists, it creates a transient session, executes the command, and automatically cleans up (closes) the session once execution finishes.
• Log Aggregation:
  • Track bulk execution progress by passing bulkExecId to ssh_exec (action status or logs).
  • Retrieve aggregated log output for all targets under the bulk ID, or filter for a specific target by specifying the connectionId, name, or host.

5. Multi-Client Organization

• Use ssh_client (action list) to inspect current client groups.
• Assign or remove connections under specific client ownerships using ssh_client with action assign or remove. This keeps server fleets clean and traceable by client context.

6. SSH Key Management

• Link stored private keys to connections using ssh_key (action link).
• Never store plaintext private keys directly inside connection files. Use ssh_key (action add) to import the private key content securely, and link it to the target connections.

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Tool Call Examples

1. Key & Connection Management

Add an SSH Private Key:

json

{
  "name": "ssh_key",
  "arguments": {
    "op": "add",
    "keyName": "prod-deploy-key",
    "privateKey": "-----BEGIN OPENSSH PRIVATE KEY-----\nb3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW\n..."
  }
}

Save a New Connection with a Linked Key:

json

{
  "name": "ssh_conn",
  "arguments": {
    "op": "save",
    "name": "production-app-server",
    "host": "192.168.1.50",
    "port": 22,
    "username": "ubuntu",
    "client": "AcmeCorp"
  }
}

Tip: After saving, link the key using:

json

{
  "name": "ssh_key",
  "arguments": {
    "op": "link",
    "keyName": "prod-deploy-key",
    "connectionId": "uuid-of-production-app-server"
  }
}

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2. Connection Lifecycle & Non-Blocking Execution

Open Session:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "open",
    "connectionId": "uuid-of-production-app-server"
  }
}

Returns: Session ID: 9f8e7d6c-5b4a-3f2e-1d0c-9b8a7f6e5d4c

Run a Command Asynchronously:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "run",
    "sessionId": "9f8e7d6c-5b4a-3f2e-1d0c-9b8a7f6e5d4c",
    "command": "apt-get update && apt-get upgrade -y"
  }
}

Returns: Command ID: a1b2c3d4-e5f6-7a8b-9c0d-1e2f3a4b5c6d

Check Status & Fetch Filtered Logs:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "status",
    "commandId": "a1b2c3d4-e5f6-7a8b-9c0d-1e2f3a4b5c6d"
  }
}

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "logs",
    "commandId": "a1b2c3d4-e5f6-7a8b-9c0d-1e2f3a4b5c6d",
    "tail": 50,
    "grep": "error"
  }
}

Disconnect Session:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "close",
    "sessionId": "9f8e7d6c-5b4a-3f2e-1d0c-9b8a7f6e5d4c"
  }
}

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3. Bulk Execution & Fleet Audits

Execute Command Across Multiple Targets (Async):

json

{
  "name": "ssh_bulk_exec",
  "arguments": {
    "commands": ["systemctl restart nginx", "systemctl status nginx"],
    "connectionIds": ["server-uuid-1", "server-uuid-2", "server-uuid-3"],
    "concurrency": 5
  }
}

Returns: bulkExecId: e8d7c6b5-a4f3-9e2d-8c1b-7a0f9e8d7c6b

Monitor Bulk Status:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "status",
    "bulkExecId": "e8d7c6b5-a4f3-9e2d-8c1b-7a0f9e8d7c6b"
  }
}

Fetch Aggregated Logs for the Bulk Run:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "logs",
    "bulkExecId": "e8d7c6b5-a4f3-9e2d-8c1b-7a0f9e8d7c6b",
    "tail": 20
  }
}

Fetch Logs for a Specific Target in a Bulk Run:

json

{
  "name": "ssh_exec",
  "arguments": {
    "op": "logs",
    "bulkExecId": "e8d7c6b5-a4f3-9e2d-8c1b-7a0f9e8d7c6b",
    "connectionId": "server-uuid-1",
    "tail": 20
  }
}

Run Bulk Security Audit (Synchronous):

json

{
  "name": "ssh_bulk_audit",
  "arguments": {
    "op": "security",
    "client": "AcmeCorp",
    "concurrency": 3
  }
}

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Execution Flow Examples

Flow 1: Persistent Single-Server Command Lifecycle

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Flow 2: Asynchronous Bulk Execution with Transient Sessions

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Edge Cases and Failure Handling

1. Connection Timeouts & Failures:

   • If ssh_exec (action open) fails, check connection credentials, firewall rules, and key links. Use ssh_conn (action test) to run diagnostics.

2. Channel Concurrency Limitations:

   • If the remote server enforces strict session channel limits (MaxSessions), concurrent executions may fail to open channels. The SSH MCP server implements a self-healing queue that detects channel failures, decreases concurrency, and retries tasks with an exponential backoff.

3. Exit Code Evaluation:

   • Always verify the command exit code in the status output. Exit code 0 indicates success. A non-zero exit code or null indicates failure or premature termination.

4. Transient Dynamic Connection Isolation:

   • If a bulk execution fails on a specific server in the fleet, the failure will remain isolated to that connection. Other fleet members will execute successfully. The failed target status will be saved with an error code and stored under the bulk ID log history for easy debugging.