{
  "paths": {
    "/availability": {
      "get": {
        "tags": ["Availability"],
        "summary": "Get calendar availability",
        "description": "Returns busy time blocks for a calendar within a given range. Includes expanded recurring event occurrences. User must have at least viewer role on the calendar. Requires `availability:read` scope.",
        "operationId": "getAvailability",
        "parameters": [
          { "name": "calendar_id", "in": "query", "required": true, "schema": { "type": "string", "format": "uuid" }, "description": "Calendar to query" },
          { "name": "start", "in": "query", "required": true, "schema": { "type": "string", "format": "date-time" }, "description": "Range start (RFC3339)" },
          { "name": "end", "in": "query", "required": true, "schema": { "type": "string", "format": "date-time" }, "description": "Range end (RFC3339)" }
        ],
        "responses": {
          "200": {
            "description": "Availability with busy blocks",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "required": ["calendar_id", "range_start", "range_end", "busy"],
                  "properties": {
                    "calendar_id": { "type": "string", "format": "uuid" },
                    "range_start": { "type": "string", "format": "date-time" },
                    "range_end": { "type": "string", "format": "date-time" },
                    "busy": {
                      "type": "array",
                      "items": { "$ref": "#/components/schemas/BusyBlock" }
                    }
                  }
                }
              }
            }
          },
          "400": { "description": "Validation error", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
          "401": { "description": "Not authenticated", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } },
          "403": { "description": "Insufficient scope or permission", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Error" } } } }
        }
      }
    }
  }
}