Skip to main content
Glama
cygnussystems

cygnus-ssh-mcp

Official

ssh_conn_add_host

Store SSH host credentials and settings in a configuration file, enabling quick connections with alias support. Requires username and host; supports password or key authentication.

Instructions

Add or update a host configuration in the host configuration TOML file. This tool will fail if the host already exists in the host config file.

You can call the 'ssh_conn_connect' tool without having to add a new host! The host may already be listed in the host config TOML file!

Authentication requires either a password OR a keyfile (or both):

  • Password authentication: Provide password

  • Key-based authentication: Provide keyfile (and optionally key_passphrase if the key is encrypted)

If using key-only authentication and sudo operations are needed, you must explicitly provide sudo_password unless the server has passwordless sudo configured.

Warn the user that credentials will be visible to the LLM and that it would be better for the user to add the host directly in the host configuration file.

The host config file is a TOML file likely in the user's home directory. The configuration will be stored under a ["user@host"] key.

Optional fields:

  • alias: A short name for connecting (e.g., 'prod' instead of 'deploy@production.example.com')

  • description: A text description of what the host is for

Returns: Dictionary with operation status

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
userYesUsername for authentication
hostYesHostname or IP address
passwordNoPassword for authentication
portNoSSH port
sudo_passwordNoPassword for sudo operations (defaults to regular password if not provided)
aliasNoShort name for easy connection (e.g., 'prod', 'staging')
descriptionNoDescription of what this host is for
keyfileNoPath to SSH private key file (e.g., ~/.ssh/id_rsa)
key_passphraseNoPassphrase for encrypted SSH key

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full burden. It discloses failure on duplicate host, authentication requirements, and credential warnings. However, it does not mention rate limits, side effects on existing configs, or details about the return dictionary beyond 'operation status'.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured with clear sections and logical flow. It is slightly verbose but each sentence provides useful information. The contradiction between 'Add or update' and 'fail if exists' could be clarified, but overall it is efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 9 parameters, 2 required, and an output schema, the description covers authentication, failure condition, optional fields, and security warnings. It mentions the config file location and key structure. It could be improved by clarifying whether the tool truly supports update (contradiction) and providing more details about the return value.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, baseline 3. The description adds value by explaining authentication options (password, keyfile, key_passphrase) and giving examples for alias and description. It clarifies the use of sudo_password and port defaults, which goes beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Add or update a host configuration' and specifies the resource (host configuration TOML file). It distinguishes from siblings by noting that 'ssh_conn_connect' can be used without adding a host, and explicitly mentions the tool will fail if the host exists, clarifying its scope.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit guidance on when to use alternatives (ssh_conn_connect), details authentication methods (password vs keyfile), advises on sudo password, and warns about credential visibility. It also explains the optional fields and the underlying storage mechanism.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/cygnussystems/cygnus-ssh-mcp'

If you have feedback or need assistance with the MCP directory API, please join our Discord server