{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://example.local/schemas/plans.json",
  "title": "Plan",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "id", "template_id", "title", "discipline", "age_group", "target_group",
    "total_minutes", "sections", "goals", "capability_summary", "created_by",
    "created_at", "source", "fingerprint"
  ],
  "properties": {
    "id": { "type": "string" },
    "template_id": { "type": ["string", "null"] },
    "title": { "type": "string", "minLength": 1 },
    "discipline": { "type": "string" },
    "age_group": { "type": "string" },
    "target_group": { "type": "string" },
    "total_minutes": { "type": "integer", "minimum": 0 },
    "sections": {
      "type": "array",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": ["name", "items", "minutes"],
        "properties": {
          "name": { "type": "string" },
          "minutes": { "type": "integer", "minimum": 0 },
          "items": {
            "type": "array",
            "items": {
              "type": "object",
              "additionalProperties": false,
              "required": ["exercise_external_id", "duration", "why"],
              "properties": {
                "exercise_external_id": { "type": "string" },
                "duration": { "type": "integer", "minimum": 0 },
                "why": { "type": "string" }
              }
            }
          }
        }
      }
    },
    "goals": { "type": "array", "items": { "type": "string" } },
    "capability_summary": { "type": "object", "additionalProperties": { "type": "integer" } },
    "novelty_against_last_n": { "type": ["number", "null"] },
    "fingerprint": { "type": "string" },
    "created_by": { "type": "string" },
    "created_at": { "type": "string", "format": "date-time" },
    "source": { "type": "string" }
  }
}