Files
alknet-firewall/docs/architecture/decisions/006-optional-pytorch.md
glm-5.1 7d8a39a88a docs: resolve 4 open questions, add research, spec codebook package structure
Research-driven resolution of OQ-01, OQ-02, OQ-05, OQ-06:

- OQ-01: Remove ONNX Runtime from scope entirely — doesn't support
  activation extraction natively (optimum #972 closed as not planned),
  bloated model exports; burn/cublas via safetensors is a better future path

- OQ-02: Codebook compresses ~65% (1,245 → 500-600 lines); add Package
  Structure and Extraction from PoC sections to codebook.md based on PoC
  analysis of metaspline firewall_codebook.py

- OQ-05: Standalone API + thin adapter pattern (ADR-011); Phase 1 ships
  Firewall.screen() only, Phase 2 adds <100-line adapter packages for
  LlamaFirewall, OpenAI Agents SDK, NeMo Guardrails

- OQ-06: TOML for file-based config — standard modern Python, two-way door

Also: research OQ-03 rolling windows from taskgraph-semantic reference code,
remove onnxruntime/optimum from dependencies, move streaming screening to
Phase 2, add burn/cublas as Phase 3 alternative backend.
2026-06-13 07:27:40 +00:00

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2.1 KiB
Markdown

# ADR-006: PyTorch as Optional Dependency
## Status
Accepted
## Context
PyTorch is the inference backend for the detector model. However, PyTorch is
large:
- `torch` (CPU): ~200MB download, ~700MB installed
- `torch` (CUDA): ~2.5GB download, ~5GB+ installed
Making PyTorch a required dependency would force a 200MB-2.5GB download on
every user, even those who already have PyTorch installed. This is the
standard problem for ML libraries, and the HuggingFace ecosystem has
converged on a solution.
## Decision
Make PyTorch an optional dependency via extras (`pip install
alknet-firewall[torch]`). The base install includes all non-ML dependencies
(sklearn, huggingface-hub, safetensors, tokenizers, numpy). ML inference
backends are installed separately.
Use lazy imports with clear error messages when PyTorch is not installed:
```python
try:
import torch
except ImportError:
raise ImportError(
"PyTorch is required for alknet-firewall inference. "
"Install with: pip install 'alknet-firewall[torch]' "
"or pip install torch --index-url https://download.pytorch.org/whl/cpu"
)
```
## Consequences
**Positive**:
- Base install is ~30MB download, ~100MB installed — very lightweight
- Users with existing PyTorch installations don't re-download
- Follows HuggingFace ecosystem conventions (transformers, safetensors, HF
hub all use this pattern)
- uv supports CPU/GPU torch variant selection via `[tool.uv.sources]` and
`[[tool.uv.index]]`
**Negative**:
- More complex dependency specification in pyproject.toml
- Users must read installation docs to choose the right extra
- Runtime import errors if users forget to install a backend
- CPU-only torch requires two-step install or uv configuration (can't be
expressed in pip extras alone)
- PyTorch is the only supported inference backend; future alternatives
(burn/cublas via safetensors) would require separate integration work
## References
- [modern-python-project-setup.md](../research/modern-python-project-setup.md) —
Section 2: PyTorch handling
- [python-ml-packaging.md](../research/python-ml-packaging.md) — Section 1:
PyTorch as dependency