undefined

Consecutive shock days are merged into regimes, with start/end/peak values output.
</principle>

<principle name="lead_lag_interpretation">
**Lead-Lag Interpretation**

Interpretation of cross-correlation results:

| lag Value | Meaning | Narrative Support Level |
|--------|------|-----------|
| lag > 0 | Natural gas leads fertilizer | High (meets expectations) |
| lag ≈ 0 | Simultaneous changes | Medium (common driving factor) |
| lag < 0 | Fertilizer leads natural gas | Low (weak narrative) |

Reasonable lead period: 1-8 weeks (7-56 days)
</principle>

<principle name="data_source_priority">
**Data Source Priority**

Primary: TradingEconomics (crawled via fully automated Chrome CDP)
Backup: FRED Henry Hub + World Bank Pink Sheet

**Fully Automated Chrome CDP Crawling**:
The script automatically completes the following steps without manual operation:
1. Automatically start Chrome debug mode
2. Open TradingEconomics page and wait for chart loading
3. Execute JavaScript via WebSocket connection to extract Highcharts data
4. Automatically navigate to multiple commodity pages (e.g., natural gas → fertilizer)
5. Automatically close Chrome after completion

Completely bypasses Cloudflare, no manual verification required.
</principle>

</essential_principles>

<objective>
Verify the causal hypothesis of "natural gas price surge → fertilizer price surge".

Output three levels of analysis:
1. **Shock Regimes**: Parabolic/surge intervals of natural gas and fertilizer
2. **Lead-Lag Test**: Lead-lag correlation analysis
3. **Narrative Assessment**: Narrative credibility judgment
</objective>

<quick_start>

**Fully Automated Mode: One-click completion of data crawling, analysis and visualization**

The script will automatically start Chrome, crawl data, close Chrome, no manual operation required.

**Step 1: Install Dependencies**
```bash
pip install requests websocket-client pandas numpy matplotlib scipy

cd scripts
python fetch_te_data.py --symbol natural-gas --symbol urea

python gas_fertilizer_analyzer.py \
  --gas-file ../data/cache/natural-gas.csv \
  --fert-file ../data/cache/urea.csv \
  --output ../data/analysis_result.json

python visualize_shock_regimes.py

**Sample Output**:
```json
{
  "signal": "narrative_supported",
  "confidence": "medium",
  "gas_shock_regimes": [
    {"start": "2026-01-20", "peak": "2026-01-22", "regime_return_pct": 29.1}
  ],
  "fert_spike_regimes": [
    {"start": "2025-10-27", "peak": "2025-10-27", "regime_return_pct": 0.0}
  ],
  "lead_lag_test": {
    "best_lag_days_gas_leads_fert": 21,
    "best_corr": 0.131
  },
  "interpretation": "Natural gas leads fertilizer by about 21 days, the narrative has quantitative support"
}

analyze-gas-fertilizer-contract-shock/
├── SKILL.md                           # This file (router)
├── skill.yaml                         # Frontend display metadata
├── manifest.json                      # Skill metadata
├── workflows/
│   ├── analyze.md                     # Full three-stage analysis workflow
│   ├── quick-check.md                 # Quick check workflow
│   └── hedge-hypothesis.md            # Contract hedge hypothesis analysis
├── references/
│   ├── data-sources.md                # Chrome CDP crawler description
│   ├── methodology.md                 # Shock detection and lead-lag methodology
│   ├── input-schema.md                # Input parameter definitions
│   └── historical-episodes.md         # Historical case comparisons
├── templates/
│   ├── output-json.md                 # JSON output template
│   └── output-markdown.md             # Markdown report template
├── scripts/
│   ├── fetch_te_data.py               # TradingEconomics CDP crawler
│   ├── gas_fertilizer_analyzer.py     # Main analysis script
│   └── visualize_shock_regimes.py     # Shock regime visualization
├── data/                              # Data cache directory
│   └── cache/                         # Cache files
└── examples/
    └── sample_output.json             # Sample output

{
  "signal": "narrative_supported | narrative_weak | inconclusive",
  "confidence": "high | medium | low",
  "gas_shock_regimes": [...],
  "fert_spike_regimes": [...],
  "lead_lag_test": {
    "best_lag_days": 12,
    "best_corr": 0.41,
    "interpretation": "gas leads fert"
  },
  "narrative_assessment": "Summary of three-stage test results",
  "artifacts": {
    "charts": ["output/gas_fert_shock.png"]
  }
}