{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "forge/event-sidecar.schema.json",
  "title": "Event Sidecar",
  "description": "Subset of event schema — token/cost/duration fields written by agents before canonical merge. All fields other than eventId are optional; presence enforcement happens on the canonical event, not the sidecar.",
  "type": "object",
  "required": ["eventId"],
  "additionalProperties": false,
  "properties": {
    "eventId":          { "type": "string", "minLength": 1 },
    "inputTokens":      { "type": "integer", "minimum": 0 },
    "outputTokens":     { "type": "integer", "minimum": 0 },
    "cacheReadTokens":  { "type": "integer", "minimum": 0 },
    "cacheWriteTokens": { "type": "integer", "minimum": 0 },
    "contextTokens":    { "type": "integer", "minimum": 0 },
    "model":            { "type": "string",  "maxLength": 120 },
    "provider":         { "type": "string",  "maxLength": 60 },
    "durationMinutes":  { "type": "number",  "minimum": 0 },
    "startTimestamp":   { "type": "string",  "format": "date-time" },
    "endTimestamp":     { "type": "string",  "format": "date-time" },
    "tokenSource":      { "type": "string",  "enum": ["reported", "estimated"] }
  }
}