RUL-001 — No pytest-xdist

Ruling

NEVER run pytest with xdist (-n auto, -n N, --numprocesses, --dist) in orchestrata-ultimate. Use the threadpool runner: python scripts/run_tests_threadpool.py or scripts/run_tests_streaming.py tests/ -j 8.

Evidence

• User corrected the default-to--n auto habit repeatedly (memory no-xdist-orchestrata, session originSessionId 0e53b714-4efe-4a43-a4a4-789ebeef5b11).
• xdist deadlocks this suite ~78% of the time (shared Redis/Neo4j/gRPC + free-threaded Prolog) — not a style preference, a correctness fact.
• xdist was PURGED session 228 after being found banned-yet-still-declared in pyproject.toml and invoked by health_check.py/agent_check.py/kimi-startup.sh/validate_ci.py (memory project-banned-libraries).

Enforcement

• hook .claude/hooks/no-xdist.sh
• banned-deps pytest-xdist
• banned-deps xdist
• gate scripts/test-review.py T15

Verification

.claude/hooks/no-xdist.sh denies any Bash tool_input containing pytest ... -n/--numprocesses/--dist; pytest-xdist/xdist are lines in .claude/banned-libraries.txt; scripts/test-review.py rule T15 flags xdist command-flag usage in test files.