# Make the estate answer for itself

> Auditors keep asking who can see what, and two reports disagree about the same number. We set up grants that hold, lineage that survives a refactor and an evaluation suite that scores every change, so the audit is a query rather than a week of digging.

Canonical: https://www.techfabric.com/solutions/explainable-estate

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## You can see the data. You cannot explain it.

The platform works. The questions that stall a programme are the ones about it rather than in it.

### Two dashboards disagree

Both are computed from real tables and neither is obviously wrong. Deciding which to believe takes a person a week and the answer does not stick.

### The service principal sees everything

It was granted broadly during a deadline in 2023 and nobody has revisited it. What an application can reach is now wider than what any of its users can.

### Nobody can score the agent

It answers. Whether it answers correctly, and whether last month's version was better, is a matter of opinion.

Governance gets retrofitted because it is invisible until the quarter it is not, and retrofitting it onto a live estate is most of what makes it expensive.

## What we install

### Catalogue and schema design

Structured around the organisation rather than the storage layout, so a grant model can follow how teams actually work.

### Grants through groups

Joining a team is what changes access. Individual grants are how an estate becomes unexplainable one exception at a time.

### Hive metastore migration

In stages, with external tables where a full move costs more than it returns. Sequencing rather than whether.

### Lineage that survives

Traceable through the transformations you actually run, so the question of where a number came from has an answer.

### An evaluation suite

Ground truth you own, running on every change, so a regression is caught by a gate rather than by a user.

### The written record

What was decided and why, which is the thing the next platform lead needs and almost never gets.

## The bar is whether it holds when asked

Every engagement here ends with a query somebody can run in front of an auditor rather than a document somebody wrote about the estate. That is a harder thing to deliver and it is the only version worth paying for.

## Questions

### We already have Unity Catalog. Is this still relevant?

Usually more so. Most rollouts stop halfway: the catalogues exist, half the estate is still external tables against the old metastore, and there is a service principal everybody has stopped asking about.

### Can you do the governance without the evaluation?

Yes, and it is a common start. They are separated here because they answer different questions, and most estates need the first before the second is worth doing.

### How do we know it stayed true?

Because the checks run rather than being scheduled. A grant model expressed through groups and an evaluation suite in the pipeline are both continuously true or continuously failing, which is the property a periodic audit cannot give you.