CI: install dev deps for lint, and test a real MCP handshake - #9
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Two problems, both of which let a broken server reach main. The lint job ran `uv run ruff check` without installing dev dependencies. ruff is declared under [project.optional-dependencies], so it needs --extra dev; without it uv installs runtime deps only and the step dies on "Failed to spawn: ruff". main has been red for at least three merges for this reason alone, which trains everyone to ignore it — the code itself is clean. The test job only asserted that the module imports. That is precisely the class of bug that just shipped: mcp 1.29 made experimental_capabilities a required argument of get_capabilities(), which raises inside the stdio task group at CONNECT time, not import time. The import check stayed green while the server was completely unusable. It now drives a real initialize + tools/list handshake over stdio and asserts tools come back. Verified both ways: the handshake passes on the current code, and fails with "server never returned a tools/list result" when the fix is reverted.
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mainhas been red for at least three merges, and not because of the code.Lint ran
uv run ruff checkwithout installing dev deps.ruffis under[project.optional-dependencies], so it needs--extra dev— otherwise the step dies onFailed to spawn: ruff. Locallyruff checkreports All checks passed!, so this was pure CI misconfiguration. A permanently-red main is worse than no CI, because it trains you to ignore it.Test only asserted that the module imports — which is exactly why the
mcp1.29 breakage reached main.get_capabilities()gained a requiredexperimental_capabilitiesargument, and the resultingTypeErrorfires inside the stdio task group when a client connects, not on import. The import check stayed green while the server was completely unusable in every Claude Code session.It now drives a real
initialize+tools/listhandshake over stdio and asserts the tools come back.Verified both directions locally:
handshake OK, 8 toolsAssertionError: server never returned a tools/list result, exit 1