# WDC Runtime Phase 12 Implementation Report

Date: 2026-08-17  
Branch: `feature/phase12`  
Base: Phase 11 (`0eaa27c9c7cc3bf3457505ed4455e6a3dbabb72e`)

## Scope

Phase 12 implements the distributed-runtime scheduling boundary without changing WDC epistemic semantics.

Added:

- `ResourceBundle`, `WorkloadSpec`, `Reservation`, `WorkloadHandle`, scheduler capabilities/status types.
- SQLite scheduler provenance: `scheduler_workloads`, `scheduler_reservations`, `scheduler_handles`.
- Executable `LocalScheduler` with logical capacity/reservation accounting, stdout/stderr/return-code capture, timeout handling, and automatic reservation release.
- Import-safe `RaySchedulerAdapter` with placement-group/resource rendering and an optional execution path that requires Ray to be installed and initialized.
- `KubernetesSchedulerAdapter` rendering `batch/v1 Job` manifests with resource requests/limits, optional `priorityClassName`, and optional `runtimeClassName`.
- Kubernetes cluster mutation is default-deny; `kubectl apply/delete` are only reachable when `allow_cluster_writes=True`.
- CLI: `scheduler adapters`, `scheduler render`, `scheduler local-run`.
- `distributed-runtime` integration demo.

## Preserved Boundaries

```text
Governor decides SHOULD-COMPUTE.
Scheduler decides WHERE/WHEN/RUN.
Scheduler records are not evidence.
Scheduling does not advance TCD parent time.
Scheduling does not grant external authority.
Kubernetes cluster writes are default-deny.
```

The integration demo explicitly verifies evidence count remains unchanged and TCD parent time remains `0 -> 0` across scheduling.

## External API Calibration

The adapter contracts were calibrated against current official documentation on 2026-08-17:

- Ray 2.56 placement groups: bundles atomically reserve resources and tasks/actors use placement-group scheduling strategies; supported placement strategies include `PACK`, `SPREAD`, `STRICT_PACK`, and `STRICT_SPREAD`.
- Kubernetes Jobs: `batch/v1` Jobs represent one-off workloads that run to completion.
- Kubernetes Pod Priority / Preemption: `priorityClassName` selects PriorityClass-based scheduling priority.
- Kubernetes RuntimeClass: `runtimeClassName` selects the configured container runtime handler and can represent a performance/isolation trade-off.

These are implementation substrates, not WDC cognition semantics.

## Verification Evidence Before Final Archive

- `python -m pytest -q`: **109 passed**.
- `python -m compileall -q src/wdc examples`: PASS.
- `git diff --check`: PASS.
- Source-tree CLI `scheduler adapters`: PASS.
- Source-tree Ray render: PASS.
- Source-tree Kubernetes render: PASS.
- Source-tree LocalScheduler execution: `SUCCEEDED`.
- Source-tree `distributed-runtime` demo: `SUCCEEDED`.
- Wheel build: PASS.
- Clean-venv wheel installation: PASS.
- Installed `wdc scheduler adapters`: PASS.
- Installed Ray/Kubernetes render: PASS.
- Installed `wdc demo distributed-runtime`: PASS.

## Environment-Limited Validation

This environment does **not** have Ray, the Kubernetes Python client, or `kubectl` installed. Therefore:

- Ray live-cluster placement-group creation / remote execution is implemented but not claimed as live-cluster verified here.
- Kubernetes live Job submission / deletion is implemented behind explicit write permission but not claimed as cluster verified here.

The verified contract is import safety, side-effect-free plan rendering, default-deny mutation, packaging, CLI availability, and executable LocalScheduler behavior.

## Final Artifact Gate

The final tracked-only Source ZIP must be extracted into a fresh directory and rerun the full test suite plus distributed-runtime demo. The final wheel must be installed into a clean venv and rerun scheduler adapter listing/render plus the distributed-runtime demo before release hashes are reported.

## Preliminary Archive Gate

- Tracked-only Source ZIP fresh extraction: **109 passed**.
- Fresh extraction compileall: PASS.
- Fresh extraction `distributed-runtime` demo: `SUCCEEDED`.
- Fresh extraction wheel build + clean-venv install: PASS.
- Installed adapter listing/render and installed `distributed-runtime` demo: PASS.

The final release artifacts are rebuilt from the completion-metadata commit and verified again before external SHA-256 hashes are reported.