# RetrieX Numeric Extreme Retrieval Fix

## Purpose

This patch sharpens retrieval for direct numeric extreme questions such as the lowest hardness threshold.

The concrete regression was:

- User asks for the lowest water-hardness threshold monitored by a Testomat.
- The correct answer is `0,02 °dH` / `Testomat 808`.
- Retrieval still allowed neighbouring runner-up product context such as `Testomat 2000` / `0,05 °dH` into the prompt.

That made the model add unnecessary comparison details although the user asked only for the lowest value.

## Change

`src/Knowledge/Retrieval/NdjsonHybridRetriever.php` now adds a conservative numeric-extreme document selection step between focused-product selection and normal dominant/spread selection.

The new mode:

- detects minimum/maximum-style technical measurement questions,
- extracts dH measurement values from the top retrieval window,
- identifies the document containing the actual extreme value,
- selects chunks from that document only,
- avoids filling the remaining prompt slots with runner-up product chunks.

New debug selection mode:

```text
sales_numeric_extreme_document
```

## Safety

The fix is intentionally narrow:

- no PromptBuilder changes,
- no prompt wording changes,
- no Shopware logic changes,
- no vector-service changes,
- no scoring config changes,
- no vocabulary changes.

It only affects technical numeric extreme questions containing measurement/context signals such as `Grenzwert`, `Messbereich`, `Wasserhärte`, `Resthärte`, `dH`, `threshold`, or `range`.

## Expected regression result

Question:

```text
Was ist der niedrigste Grenzwert für die Wasserhärte, welcher mit einem Testomaten überwacht werden kann?
```

Expected answer should stay focused on:

```text
0,02 °dH / Testomat 808
```

It should not add the runner-up product/value such as:

```text
Testomat 2000 / 0,05 °dH
```

unless the user explicitly asks for comparison, alternatives, or all available values.

## After applying

Run:

```bash
php bin/console cache:clear
php bin/console mto:agent:config:validate
php bin/console mto:agent:regression:test
```

Then manually retest the known 1.4.2 baseline and the lowest-threshold prompt above.