physicalai-runtime-loading-exported-policies

# Loading Exported Policies Runtime loads Studio export directories (or Hub snapshots that mirror them) through `InferenceModel` in `src/physicalai/inference/model.py`. Manifest parsing lives in `src/physicalai/inference/manifest.py`; backends register in `src/physicalai/inference/adapters/registry.py` (`onnx` → `.onnx`, `openvino` → `.xml`). Hub downloads use `src/physicalai/inference/utils/_hub.py`. ## Workflow 1. **Identify the artifact**: local export directory or Hub `repo_id`, expected backend, and whether the user needs `select_action` vs `predict_action_chunk`. - Done when: load path and API entry point are chosen before editing code. 2. **Load with auto-detection first** (local): ```python from physicalai.inference import InferenceModel model = InferenceModel("./exports/act_policy") ``` - Done when: `model` constructs without explicit `backend=` when artifacts match a registered extension. 3. **Hub load** when the package is published: ```python model = InferenceModel.from_pretrained("OpenVINO/act-fp16-ov", revision="<commit-sha>") ``` - Done when: revision is pinned for reproducibility when security or CI matters. 4. **Explicit backend** only when auto-detection is ambiguous: ```python model = InferenceModel("./exports/act_policy", backend="openvino", device="CPU") ``` 5. **Validate structure** against `references/export-load-contract.md` and backend notes (`references/onnx.md`, `references/openvino.md`). - Done when: manifest, model file, and processor artifacts resolve under the export directory. 6. **Smoke inference** without owning robot timing: ```python model.reset() action = model.select_action(observation) ``` - Done when: one forward pass succeeds on representative observation keys/shapes. For hardware loops, hand off to `physicalai-runtime-running-policy-on-robot`. ## Validation loop ```bash uv run pytest tests/unit/inference/test_model.py tests/unit/inference/test_manifest.py -q ``` For adapter changes, add or run targeted tests under `tests/unit/inference/`. ## Required checks - Export directory contains backend model file(s) and `manifest.json` consistent with `docs/reference/manifest-schema.md`. - Metadata input/output/feature names align with preprocessors in the manifest. - Optional backends fail with clear install guidance (`onnxruntime`, OpenVINO). - Do not document a backend unless an adapter is registered in `src/physicalai/inference/adapters/`. - Hub loads must not log tokens; prefer pinned `revision=` for production docs. ## References - `references/export-load-contract.md` — consumer-side contract (coordinate with Studio export skill). - `references/onnx.md`, `references/openvino.md` — adapter constraints.