{
  "type": "object",
  "properties": {
    "condition": {
      "type": "string",
      "description": "Disease / condition to search (medical name and/or abbreviation)"
    },
    "lat": { "type": "number", "description": "Patient latitude" },
    "lon": { "type": "number", "description": "Patient longitude" },
    "radius_miles": { "type": "integer", "description": "Search radius in miles" },
    "phases": {
      "type": "array",
      "items": { "type": "string" },
      "description": "Phase numbers to filter e.g. ['1','2','3']. IMPORTANT: Never enumerate all phases to mean 'all phases' — pass an empty array [] instead. NA-phase trials (device feasibility, unphased studies) only appear when phases=[] (no filter). Ignored for EAP."
    },
    "study_type": {
      "type": "string",
      "enum": ["INTERVENTIONAL", "EXPANDED_ACCESS", "OBSERVATIONAL"],
      "description": "INTERVENTIONAL (default) for clinical trials; EXPANDED_ACCESS for EAP/compassionate use; OBSERVATIONAL for observational studies."
    }
  },
  "required": ["condition", "lat", "lon", "radius_miles"]
}