otg-mcp: 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

MCP server exposing Open Traffic Generator (OTG) operations — configure flows, start/stop traffic, capture packets, read metrics — against one or more traffic generators (Ixia-C, IxNetwork, anything snappi can talk to). Python 3.11–3.12, src/ layout, package otg_mcp.

Commands

CI uses uv; use it locally too.

uv venv && uv pip install -e ".[dev,test]"

uv run pytest                                  # full suite (pytest addopts always adds coverage)
uv run pytest tests/test_server.py             # one file
uv run pytest tests/test_server.py::test_name  # one test
uv run pytest -p no:cacheprovider --no-cov ... # skip coverage when iterating

uv run ruff check .
uv run mypy src/        # CI type-checks src/ only, not tests/
uv build

Caveat on ruff: the dependency is unpinned (ruff>=0.11.7) and no select is configured, so a modern ruff (0.16.x) reports ~235 pre-existing violations across src/ and tests/ that older versions did not flag. Judge your own changes with uv run ruff check --select E4,E7,E9,F <files> and do not mass-fix the backlog as a side effect of an unrelated change.

Run the server:

python -m otg_mcp --config-file examples/trafficGeneratorConfig.json [--transport stdio|sse]

Deploying a generator: cd ansible && docker compose run --rm ansible deploy (Ansible roles, runs in a container; see ansible/README.md). Ansible is deliberately absent from pyproject.toml — it is pinned in ansible/requirements.txt and installed only into that container, so the production and test dependency sets are unaffected.

The playbook declares interfaces explicitly rather than auto-detecting them. The shell script this replaced guessed, and its guess could select the host's management NIC; it also silently accepted dead links (on one host it chose eth1/eth2/eth3, which do not exist there, leaving a traffic engine bound to nothing while every check still passed).