io.github.shigechika/junos-mcp

get_device_facts

Retrieve essential Junos device facts including model, hostname, serial number, software version, and more by providing the target hostname and optional configuration file path.

Instructions

Get basic device information (model, hostname, serial, version, etc.).

Args: hostname: Target device hostname (must exist in config.ini) config_path: Path to config.ini (empty string uses default search)

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "hostname": "<hostname>"
    },
    "name": "get_device_facts"
  }
}

Input Schema

Name	Required	Description	Default
`hostname`	Yes
`config_path`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 26, 2026

TDQS

A3.5/5.0

Behavior2/5

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

With no annotations, the description carries full burden. It mentions hostname must exist in config.ini but does not describe behavior on failure (e.g., error handling, return format), or what happens if config_path is invalid. This is insufficient for a read operation that could fail.

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 relatively short (one sentence + Args block) and front-loaded with the purpose. Every sentence adds value, though the Arg descriptions could be integrated into a more fluent structure without losing clarity.

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 low parameter count (2), presence of an output schema (which will describe return values), and no nested objects, the description adequately explains what the tool does and the key parameters. It could mention what 'basic device information' includes beyond the examples, but the output schema likely covers that.

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 description coverage is 0%, but description adds meaning beyond schema: hostname must correspond to a device in config.ini, config_path uses default search if empty. This clarifies the source of the hostname and the optional file path.

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 'Get basic device information (model, hostname, serial, version, etc.)' which is a specific verb+resource combination. It distinguishes from siblings like get_version and get_router_list by focusing on a broad set of facts.

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

Usage Guidelines2/5

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

No guidance on when to use this tool versus siblings (e.g., get_version for just version, get_router_list for inventory). The description only notes prerequisites (hostname must exist in config.ini) but lacks usage context or alternatives.

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