docs/LIMITATIONS.md

# Sofia Engine Operating Boundaries & Transparent Limitations

In accordance with our engineering principle **"Evidence beats claims"**, the following boundaries and limitations apply to Sofia Engine 3.0.0a1:

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## 1. Checkpoint Distribution Status
- **No Canonical Pretrained Foundation Model:**
  Sofia Engine 3.0.0a1 is a **Scientific & Edge Intelligence Runtime**, not a foundation model. No pre-trained neural checkpoint is distributed in this initial release.
  Future trained checkpoints (e.g. bearing fault classifiers, transformer-based time-series anomaly models) will be distributed with explicit training provenance, evaluation reports, and SHA-256 digests.

## 2. Hardware & Fixed-Point Numerical Differences
- **C99 vs. Python Floating-Point:**
  The Python runtime operates in IEEE 754 double precision (64-bit float). The C99 embedded reference engine supports both single precision (32-bit float) and Q16.16 fixed-point arithmetic. Fixed-point computations have a finite resolution of $\approx 1.526 \times 10^{-5}$ and may exhibit small truncation differences compared to 64-bit float baselines.

## 3. Standards Compliance Scope
- **Relevance vs. Formal Certification:**
  Sofia Engine implements calculations relevant to industrial standards (e.g., ISO 10816/20816 vibration severity zones, IEEE 519 harmonic limits, IEC 61000-4-30 power quality concepts). **Software implementation does not constitute formal device or system-level certification.** Certified deployments require end-to-end hardware calibration and formal test laboratory certification.

## 4. Operational Safety Notice
- **Non-Replacement of Qualified Engineering Judgment:**
  Diagnostic outputs (Health Scores, Severity classifications, Anomaly events) are mathematical inferences based strictly on incoming sensor telemetry. They do not replace certified human inspection or qualified engineering judgment.
- **Physical Safety Interlocks:**
  Sofia Engine outputs must never be connected directly to emergency stops, circuit breakers, or critical plant actuators without independent, hardwired, safety-certified physical interlocks (e.g. SIL-rated safety relays).