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.
2.9 KiB
ADR-011: Standalone API with Thin Adapter Integration Strategy
Status
Accepted
Context
alknet-firewall provides behavioral signal detection — fundamentally different from text-surface defenses like Llama Guard, NeMo Guardrails, or Guardrails AI. It requires running a small detector model and extracting hidden state activations, not classifying input text. Users may want to run both text-surface defenses and behavioral detection in series.
Research into existing guardrail systems (patterns-analysis.md) identified three viable integration targets with high compatibility:
- LlamaFirewall:
BaseScanner.scan()→ScanResultmaps directly toFirewall.screen()→Alarm - OpenAI Agents SDK:
@input_guardraildecorator pattern with blocking execution - NeMo Guardrails: Custom Python action in input rails (Colang DSL can't express behavioral detection natively)
Two systems have low compatibility: Guardrails AI (expects text-surface validators with content fixes, not alarms) and Amazon Bedrock Guardrails (closed service, no extension mechanism).
Decision
Phase 1: Ship a standalone API only. No adapters, no common interface.
# The core API — simple, composable, no framework dependencies
firewall = Firewall()
alarm = firewall.screen("untrusted input text")
Phase 2: Build thin adapter packages as optional dependencies. Each adapter is <100 lines and has no impact on the core library:
alknet-firewall-llamafirewall: CustomBaseScannersubclassalknet-firewall-agents:@input_guardrailwrapperalknet-firewall-nemo: Custom NeMo input rail action
Do NOT build a common ScreeningProvider interface. The integration patterns
differ enough between systems that a shared abstraction would be premature and
constraining. If a common pattern emerges organically from the adapters,
extract it then.
Consequences
Positive:
- Phase 1 ships faster — no adapter development or testing overhead
- Core API stays clean and framework-independent
- Users can compose manually: call
firewall.screen()then pass results to any guardrail system - Adapters are optional packages, not core dependencies — no coupling
- Thin adapters are easy to maintain when guardrail frameworks change their APIs
Negative:
- Phase 1 users must write their own glue code (typically 5–10 lines)
- No "pip install and configure" experience until Phase 2
- Multiple small adapter packages to maintain
- Risk of API drift between core and adapters if adapters are maintained infrequently
References
- OQ-05 — How should the firewall integrate with existing guardrail systems?
- patterns-analysis.md — Full research analysis
- ADR-002 — Behavioral signal detection (not text classification)