{
  "schema_id": "WetlandChange",
  "version": "0.1",
  "description": "Detect changes in wetland extent, marsh vegetation state, or shallow-water inundation between before/after Sentinel-2 tiles.",
  "class_match": "WET",
  "bands_required": ["B03", "B08", "B11"],
  "band_rationale": "Green + NIR + SWIR1 captures wetland vegetation state and shallow-water contrast better than RGB alone.",
  "predicate": "Has a wetland, marsh, or shallow-water area changed extent or vegetation state between the before and after tiles?",
  "fields": {
    "severity": {"type": "enum", "values": ["low", "moderate", "high", "extreme"]},
    "direction": {"type": "enum", "values": ["expansion", "contraction", "vegetation_shift", "drying", "inundation"]},
    "area_fraction": {"type": "number", "range": [0.0, 1.0]},
    "vlm_explanation": {"type": "string"},
    "confidence": {"type": "number", "range": [0.0, 1.0]}
  },
  "negative_output": null,
  "negative_instruction": "If the wetland looks unchanged, return null."
}