# M9 Regression Map

These are the most likely regressions during autonomous builds.

## API Envelope Drift

Risk: some endpoints return raw data while others return envelopes.

Prevention:

- central response helper,
- API client tests,
- sample responses.

## Geometry Stored Incorrectly

Risk: GeoJSON stored as text everywhere.

Prevention:

- PostGIS geometry columns,
- schema tests,
- validation utilities.

## Demo Data Masquerades as Real Data

Risk: UI shows fixture metrics without labeling them.

Prevention:

- source_mode field,
- demo badge,
- no fallback-to-fixture for external failures.

## Frontend State Duplication

Risk: every component fetches differently.

Prevention:

- central API client,
- shared hooks,
- state contracts.

## Heavy AI Implemented Too Early

Risk: Codex spends time on YOLO/SAM before storage and datasets work.

Prevention:

- pass scorecards,
- V1 ordering,
- disabled state for model features.

## CRS Ignored

Risk: area/length values wrong.

Prevention:

- CRS field mandatory,
- projected calculations documented,
- geospatial edge cases.

## Docs Not Updated

Risk: implementation diverges from specs.

Prevention:

- Definition of Done includes docs,
- execution log mandatory.

## Root Folder Pollution

Risk: scripts and generated outputs appear at root.

Prevention:

- repository conventions,
- review script.