# 📐 L2 Spec — Mammographic Breast Density Classification BI-RADS (PWDR) — Spec Skeleton
**ID:** `L2-515-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-515`](/artifact/l1/L1-515)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553363
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| Kvp | — | 25 – 35 |
| Mas | — | [NEEDS_HAND_AUTHORING: bounds] |
| H proj | — | 1024 – 5500 |
| Snr db | dB | [NEEDS_HAND_AUTHORING: bounds] |
| W proj | — | 1024 – 4500 |
| Pixel size um | µm | 50 – 200 |
| Filter material | — | [NEEDS_HAND_AUTHORING: bounds] |
| Anode target material | — | [NEEDS_HAND_AUTHORING: bounds] |
| Exposure factor drift | — | [NEEDS_HAND_AUTHORING: bounds] |
| Compression thickness mm | mm | 20 – 90 |
| Age related density shift | — | [NEEDS_HAND_AUTHORING: bounds] |
| Calibration phantom uncertainty | — | [NEEDS_HAND_AUTHORING: bounds] |
| Automated vs radiologist disagreement | — | [NEEDS_HAND_AUTHORING: bounds] |
| Compression thickness calibration error | — | [NEEDS_HAND_AUTHORING: bounds] |
## 2. Tolerance (ε)
**Type:** `fn`
```
0.85_accuracy
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`98e4f42bd411396205ff4992368a27318a313dab3562928ffec21109e7d621ee`
## 5. On-chain Registration
- **Chain hash:** `0x357eabe1dfd57f7610fc63e99fe63ef1f8b717f2f2afba91e2bfa236f160dd8e`
- **Chain tx hash:** `0x47dd9e00c22ab61788e51d1b94439adb03aefc03c3058f72f1f928c04f7fbf0c`
- **Chain block:** `41553363`
---
## File Mapping
This bundle consists of: `L2-515-001.md`, `L2-515-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-515-001.md` | Source of truth — edit this | Human or LLM |
| `L2-515-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-515-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._