[audit] 17 core/ modules import os or pathlib (core must be zero-I/O) #560

Severity

MEDIUM (defer is OK with explicit follow-up)

Audit lens

architect (decomposition / dependency direction)

Finding

17 modules under mcp_server/core/ import os or pathlib. The layer rule forbids it: core is zero-I/O business logic and bans os/pathlib even though they are stdlib (docs/module-inventory.md:77-86, docs/agent-guidance.md § Code Style).

All 17 are grandfathered as layer-violation entries in .craftsmanship-baseline.json, so CI passes, but the debt is real:

• ablation.py, abstention_gate.py, codebase_graph.py, conflict_monitor.py
• pg_recall_weights.py (CORTEX_DECAY_DISABLED / CORTEX_HEAT_CONSTANT read at :77-78)
• recall_pipeline.py (_env_float at :52-62 for CORTEX_HOPFIELD_BETA, CORTEX_HDC_BETA, CORTEX_SA_BETA)
• reconsolidation.py, reranker_model.py, retrieval_dispatch.py, telemetry.py, thermodynamics.py
• wiki_axis_registry.py, wiki_coverage.py, wiki_coverage_dashboard.py, wiki_drift.py, wiki_file_doc_skeleton.py, wiki_groomer.py

Most are environment-variable reads (feature flags, ablation switches, tuning constants) evaluated inside core; the wiki modules touch the filesystem.

Evidence required to close

python scripts/check_craftsmanship.py passes with the 17 os/pathlib layer-violation entries pruned from .craftsmanship-baseline.json, and the full test suite plus benchmarks/reproduce.sh --no-regression show no change in behavior.

Suggested remedy

Read the environment and the filesystem at the boundary (handlers or infrastructure, e.g. infrastructure/memory_config.py) and pass the resolved values into core as arguments or a frozen settings object. Moving the os.environ reads into shared/ would satisfy the import whitelist while keeping I/O on core's call path, so it is not an acceptable fix. Can land in several PRs (retrieval flags, ablation, wiki filesystem), each pruning its own baseline entries.