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Trust & Audit

CircuitKit ships 13 discovery algorithms across 4 backends with explicit stability tiers, and a 6-pillar faithfulness evaluation framework. Shipping is not validation: only 2 (eap, eap-ig) are validated at production scale, acdc and ibcircuit are experimental (GPT-2 scale), and the other 9 are research (GPT-2 IOI only). This section documents what has been validated, what is experimental, and how the algorithms were audited.

Where to look

Scope & Limitations Stability tier definitions, algorithm maturity, known limitations
Audit Results What the algorithms actually did on real models — empirical results

How CircuitKit labels algorithms

Every algorithm has a stability tier, displayed next to its name throughout these docs:

Tier Badge Meaning Count
Stable Validated across model families (GPT-2 through 3B+). Used in the audit paper. 2
Experimental Works on GPT-2 scale; may fail on larger models, GQA, or instruction-tuned architectures. 2
Research GPT-2 IOI only. For algorithm comparison studies or paper replication. Not validated on modern architectures. 9

The honest finding

The CircuitKit audit paper ("Faithfulness Is Not Actionability", EMNLP Findings 2026) evaluated the core discovery algorithms across 6 faithfulness pillars and found:

  • Stable-tier algorithms (EAP family) produce circuits with high faithfulness (≥0.85 ablation_score) across GPT-2, Llama-3.2-3B, and Gemma-2-2B.
  • Experimental algorithms (ACDC, IBCircuit) produce smaller circuits but with lower faithfulness — they are valid for research but not yet production-ready. Both were only validated at GPT-2 scale, and IBCircuit OOMs above ~3B parameters on a single GPU.
  • Research algorithms are unvalidated beyond GPT-2 IOI. Do not cite findings from them without independent verification.

See Audit Results for per-algorithm scores.