junos-mcp-server: Instructions file for Claude Code

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

This is a Model Context Protocol (MCP) server for Juniper Junos network devices. It enables LLMs to interact with Juniper network equipment through a standardized interface using the FastMCP framework and Juniper's PyEZ library.

Key Commands

Running the Server

# Install dependencies
pip install -r requirements.txt

# Run with stdio transport (for Claude Desktop)
python3.11 jmcp.py -f devices.json -t stdio

# Run with streamable-http transport (for VSCode)
python3.11 jmcp.py -f devices.json -t streamable-http -H 127.0.0.1 -p 30030

# Docker build
docker build -t junos-mcp-server:latest .

# Docker run (stdio)
docker run --rm -it -v /path/to/devices.json:/app/config/devices.json junos-mcp-server:latest

# Docker run (streamable-http)
docker run --rm -it -v /path/to/devices.json:/app/config/devices.json -p 30030:30030 junos-mcp-server:latest python jmcp.py -f /app/config/devices.json -t streamable-http -H 0.0.0.0

Testing and Development

• Run the unit tests with make test (or python -m unittest discover -s tests -v)
• Code style is enforced with Black (configured in pyproject.toml); check with black --check . and auto-format with black .. CI runs Black and the unit tests (.github/workflows/ci.yml).
• Live testing against devices requires a valid Junos device configuration in JSON format

Architecture

The server implements 10 MCP tools in jmcp.py:

1. execute_junos_command - Execute arbitrary CLI commands on routers
2. execute_junos_command_batch - Execute the same command on multiple routers in parallel
3. execute_junos_pfe_command - Execute a PFE (packet forwarding engine) command on an FPC
4. get_junos_config - Retrieve device configuration (uses show configuration | display inheritance no-comments)
5. junos_config_diff - Compare configuration versions (rollback comparison)
6. render_and_apply_j2_template - Render a Jinja2 template and load/commit it
7. gather_device_facts - Collect device information using PyEZ facts
8. get_router_list - List available routers from the configuration
9. load_and_commit_config - Apply configuration changes (supports set/text/xml formats); always runs a commit check first, with optional dry_run and confirm_timeout_mins (commit confirmed)
10. confirm_commit - Confirm a pending commit confirmed so the device does not roll back