## What
Adds a docs page teaching app developers how to reference auto-created
**system fields** (`createdAt`, `updatedAt`, `id`, …) from views and
other entities, and makes the API it documents real by exporting
`generateDefaultFieldUniversalIdentifier` from the SDK.
## Why
System fields are provisioned by the server, so they're never declared
with `defineField()` and have no importable `universalIdentifier`
constant. Since 2.19 their universal identifier is derived
deterministically from the application id, the object id and the field
name. Hardcoding an invented id fails sync with `INVALID_VIEW_DATA:
Field metadata not found` (this is exactly what broke the
twenty-partners `createdAt` view column).
The twenty-partners app already imports
`generateDefaultFieldUniversalIdentifier` from `twenty-sdk/define`, but
the function was never exported from the SDK. This PR adds the export
and documents the pattern.
## Changes
- **New page** `data/system-fields.mdx` — "Targeting System Fields":
- Lists the 8 system fields (`id`, `createdAt`, `updatedAt`,
`deletedAt`, `createdBy`, `updatedBy`, `position`, `searchVector`).
- Explains the deterministic derivation and the sync error from
hardcoding ids.
- Documents `generateDefaultFieldUniversalIdentifier({
applicationUniversalIdentifier, objectUniversalIdentifier, fieldName })`
with a full `defineView` example.
- Contrasts with standard objects (use
`STANDARD_OBJECT_UNIVERSAL_IDENTIFIERS.<object>.fields.<field>.universalIdentifier`)
and notes that `name` is a default, not system, field.
- **SDK export** — new `generate-default-field-universal-identifier.ts`
wrapping the existing `getFieldUniversalIdentifier` from
`twenty-shared/application` (`name` → `fieldName`), exported from
`define/index.ts`.
- Registered the page in `docs.json` (Data group) and cross-linked it
from the Views doc.
## Notes
`node_modules` isn't installed in this environment, so `nx typecheck`
wasn't run. The wrapper is a signature-matched pass-through and the
`twenty-shared/application` subpath + `getFieldUniversalIdentifier`
barrel export were both verified to exist.
---
_Generated by [Claude
Code](https://claude.ai/code/session_017B7VivHcqZYjn3ukestY9U)_
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Co-authored-by: github-actions <github-actions@twenty.com>
Paul Rastoin
