{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "SOMA acquisition frame v2 — DESIGN, not legacy Rust wire format",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "version",
    "sessionId",
    "clockId",
    "frameSequence",
    "streams"
  ],
  "properties": {
    "version": {
      "const": 2
    },
    "sessionId": {
      "type": "string"
    },
    "clockId": {
      "type": "string"
    },
    "frameSequence": {
      "type": "integer",
      "minimum": 0
    },
    "streams": {
      "type": "array",
      "minItems": 1,
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "modality",
          "channelId",
          "unit",
          "sampleRateHz",
          "firstSampleIndex",
          "firstTimeNs",
          "samples",
          "flags"
        ],
        "properties": {
          "modality": {
            "enum": [
              "CAP",
              "ECG",
              "PPG_RED",
              "PPG_IR",
              "IMU"
            ]
          },
          "channelId": {
            "type": "string"
          },
          "unit": {
            "enum": [
              "pF",
              "mV",
              "count",
              "g",
              "deg/s"
            ]
          },
          "sampleRateHz": {
            "type": "number",
            "exclusiveMinimum": 0
          },
          "firstSampleIndex": {
            "type": "integer",
            "minimum": 0
          },
          "firstTimeNs": {
            "type": "string",
            "pattern": "^[0-9]+$",
            "description": "64-bit monotonic timestamp as decimal string; avoid JS integer overflow"
          },
          "adcOffsetNs": {
            "type": "integer"
          },
          "filterDelayNs": {
            "type": "integer",
            "minimum": 0
          },
          "samples": {
            "type": "array",
            "minItems": 1,
            "items": {
              "type": "number"
            }
          },
          "flags": {
            "type": "array",
            "items": {
              "enum": [
                "clipped",
                "dropout",
                "contact_loss",
                "motion",
                "clock_unsynced",
                "warmup",
                "resampled"
              ]
            }
          },
          "sourceRateHz": {
            "type": "number",
            "exclusiveMinimum": 0
          },
          "pipelineId": {
            "type": "string"
          }
        }
      }
    },
    "calibrationId": {
      "type": "string"
    },
    "layoutId": {
      "type": "string"
    }
  }
}