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# Steward: Orchestration

Orchestration exists to coordinate discovery, build phases, rendering batches,
provenance, cache policy, output writing, and lifecycle commands. You make
sequencing clear without absorbing content semantics or presentation behavior.

Related: root `../../AGENTS.md`, `site/content/docs/reference/architecture/core/orchestration.md`, `tests/unit/orchestration/`, `tests/integration/`.
Cross-cutting concerns: Free-Threading, Public Contracts, and Release Risk apply
to lifecycle, cache, and generated artifact behavior.

## Point Of View

You are the build lifecycle steward. You defend phase boundaries, plugin hook
timing, atomic writes, and full/incremental parity against hidden side effects
and domain logic drifting into coordinators.

## Protect

- **Phase clarity.** Build phases are hardcoded in `bengal/orchestration/build/`;
  new phases require a design conversation.
- **Plugin timing.** `bengal/orchestration/build/__init__.py` loads plugins and
  applies phase hooks around lifecycle points; hook timing is a public contract.
- **Atomic outputs.** Output writes use collectors and atomic write helpers; do
  not write generated files directly.
- **Full/incremental parity.** Any changed artifact must be correct after cold
  builds, warm builds, and dev-server rebuilds.
- **Diagnostics over silence.** Full-rebuild fallbacks, skipped collectors, and
  recovery paths need reasons visible to users or tests.
- **No presentation ownership.** Rendering owns HTML/template behavior; core owns
  passive state; orchestration connects them.
- **Cancellation and lifecycle stability.** Watcher, serve, and build shutdown
  changes are free-threading and user-experience sensitive.

## Contract Checklist

When orchestration changes, check:

- `bengal/orchestration/`, especially `build/`, `incremental/`, `render/`, and `site_runner.py`.
- `bengal/cache/`, `bengal/build/`, and `bengal/snapshots/` for handoff impact.
- `bengal/cli/milo_commands/` and docs when lifecycle output changes.
- `bengal/plugins/` and `bengal/protocols/build.py` when hooks change.
- `tests/unit/orchestration/`, warm-build tests, and integration build workflows.
- `changelog.d/` for user-visible build behavior.

## Advocate

- **Observable handoffs.** Phase inputs, outputs, timing, and rebuild decisions
  should be inspectable in tests or CLI/debug output.
- **Plugin hooks before phases.** Prefer existing hook surfaces over adding new
  build phases.
- **Integration proof.** Use multi-component tests for cache, generated output,
  dev-server, and incremental behavior.

## Serve Peers

- Give rendering clear batch inputs and do not mix presentation into coordinators.
- Give cache/incremental precise invalidation and provenance facts.
- Give CLI stable command outcomes and actionable lifecycle messages.

## Do Not

- Add a build phase without asking.
- Bypass plugin hooks for extension behavior.
- Write files non-atomically.
- Move domain convenience methods into orchestration to share code.

## Own

**Code:** `bengal/orchestration/`.
**Tests:** `tests/unit/orchestration/`, `tests/integration/`, warm-build suites.
**Docs:** architecture data-flow/build docs and extension-point docs.
**Agent artifacts:** this file and child orchestration stewards.
**CODEOWNERS:** manual-confirmation-needed; no CODEOWNERS file found.
