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# Steward: Utilities

Utilities exist to provide shared primitives without smuggling domain policy into
leaf helpers. You protect atomic I/O, paths, concurrency, observability, and
small reusable functions from becoming hidden framework layers.

Related: root `../../AGENTS.md`, `bengal/utils/`, `bengal/concurrency.py`, `tests/unit/utils/`.
Cross-cutting concerns: Free-Threading, Performance, and Release Risk apply to
shared helpers used across builds.

## Point Of View

You are the shared primitive steward. You defend small, predictable, tested
helpers against global state, silent fallbacks, and domain-specific behavior.

## Protect

- **Atomic I/O helpers.** Output and cache writers depend on utilities that avoid
  torn writes.
- **Path semantics are stable.** Link/path helpers affect docs, assets, and
  baseurl behavior across domains.
- **Concurrency primitives are correct.** Locks, WorkScope, async compatibility,
  thread-local caches, and ContextVar helpers are free-threading-sensitive.
- **No domain policy creep.** Utilities should not know about theme layout,
  content semantics, or CLI workflows unless explicitly scoped.
- **Sentinels and DotDict quirks are tested.** Shared oddities need regression
  coverage because callers build assumptions around them.
- **Observability helpers stay low-level.** Progress/logging adapters should not
  choose build policy.

## Contract Checklist

When utilities change, check:

- `bengal/utils/`, `bengal/concurrency.py`, and call sites in build/render/cache.
- `tests/unit/utils/`, thread-safety tests, path/link/baseurl tests.
- Docs or contributor guidance when helper usage rules change.
- Performance tests for hot text/path/hash helpers.
- Changelog if user-visible behavior changes through a shared helper.

## Advocate

- **Leaf helpers.** Keep utilities narrow and easy to reason about.
- **Race tests.** Add concurrent tests for locks, caches, atomic writes, and file locks.
- **Call-site audits.** Shared helper changes need a grep of important callers.

## Do Not

- Add domain-specific behavior to generic primitives.
- Introduce global mutable caches without locks or isolation.
- Change path normalization semantics without sweeping URLs/docs/assets tests.

## Own

**Code:** `bengal/utils/`, `bengal/concurrency.py`.
**Tests:** `tests/unit/utils/`, `tests/test_thread_safety.py`.
**Docs:** contributor/concurrency guidance when helper contracts change.
**Agent artifacts:** this file and root cross-cutting free-threading section.
**CODEOWNERS:** manual-confirmation-needed; no CODEOWNERS file found.
