# Sofia Engine Checkpoint & Artifact Registry

This directory defines the distribution and security policy for future trained Sofia model checkpoints and parameter sets.

---

## 1. Current Checkpoint Status

> **Canonical Pretrained Checkpoint:** *Not yet released.*
>
> Sofia Engine 3.0.0a1 provides the runtime engine, feature extraction contracts, assembly virtual machine, and safe serialization interfaces. No pre-trained foundation model weights are shipped in this release.

---

## 2. Checkpoint Release Policy

Every future checkpoint published under this repository must satisfy the following technical requirements:

1. **Safe Serialization Formats**:
   - Primary: `.safetensors` or validated `.npz` (via `np.savez`).
   - **Prohibited:** Python `pickle` (`.pkl`, `.pickle`, `.pt` containing arbitrary executable code) is strictly forbidden.
2. **Cryptographic Integrity**:
   - Every artifact file must be accompanied by its lowercase SHA-256 digest (`parameters_sha256`).
   - Manifests are verified before weights are mapped into memory.
3. **Declared Feature Schema**:
   - The checkpoint manifest must explicitly declare its input `feature_schema` (e.g., `vibration-v3`, `power-quality-v1`) to prevent feature order mismatches.
4. **Transparent Provenance**:
   - Public release notes must specify training dataset origin, sample count, evaluation metrics, and runtime version compatibility.