# C910 — State the common measurement-and-construction schema

## Question

How do the families fit together without erasing their source distinctions?

## Inputs

```json
{}
```

## Sources

```json
[
  "C831 baseline",
  "C849,858,870,889,900,909"
]
```

## Opened utc

2026-09-28T02:56:54.066194+00:00

## Results

```json
{
  "schema": {
    "path": "model/unified_family_schema.json",
    "sha256": "39e20f67fe16cbacc00a3775111c47182d0a37065864794b2ffdd42d4a953691",
    "bytes": 1586
  }
}
```

## Finding

The larger picture is a shared measurement-and-construction grammar. Regular, cumulative, Rounded, list, NT, inverse, Key and Covenant families differ in the source structure or measurement they retain, while reusing a small set of explicit operations.

## Reassessment

Checkpoint80 actions, then make the explanation constructive and reader-facing.

## Checks

```json
{
  "five_operations": true,
  "six_source_fields": true,
  "limits": true
}
```

## Closed utc

2026-09-28T02:56:54.066578+00:00

## Record provenance

Exact record hash: `d1719eab3ce62dccfc5ea61ccc45111f5aa6839e27701dea88272fc676668c8d`

Source journal: `Research_Cycles/C0832_C0931/journal.json`