# Experiment 60B.26 — Proposition Question Formulation Fix

**Branch:** `feature/proposition-question-shape-v0.30`  
**Date:** 2026-08-13  
**Status:** COMPLETE

## Objective

Implement the smallest deterministic fix so `whether...` propositions are turned into concise evidence questions without carrying explanatory rationale, while preserving direct interrogatives and wh-questions.

## 60B.25 Diagnosis Applied

60B.25 isolated two deterministic causes:

1. `extractMeaning(...)` returned the full description, including explanatory rationale.
2. `isInterrogativeMeaning(...)` treated `whether...` propositions as if they were already finished direct questions.

The intended correction was:

> clean unresolved proposition + existing evidence framing

not grammatical rewriting into `Will/Does/Is...`.

## Exact Proposition-Extraction Rule

The bounded extraction change stays inside `lib/graph/question-formulator.js`.

For the existing narrow path where:

- the label is nominal / status-like (`status|likelihood|probability|chance|risk|uncertainty`)
- and the description begins with `whether...`

the formulator now extracts only the proposition portion.

Implemented rule:

- match `whether ...`
- stop at the first clear rationale boundary:
  - `;`
  - `, so that ...`
  - `, because ...`
  - `matters because ...`

This is bounded to explicit `whether...` proposition extraction only. It is **not** a global semicolon truncation rule.

## Exact Whether / Evidence-Framing Rule

The formulator now distinguishes:

- **direct interrogatives**
  - `Will our largest client leave if we relocate?`
  - `What would change the preferred option?`
- **indirect unresolved propositions**
  - `whether the supplier will renew the contract`

`whether...` is no longer treated as a direct interrogative.

Instead, it is routed through the existing deterministic evidence phrasing:

```text
What evidence would clarify whether X?
```

No subject/auxiliary inversion was added.

## Preserved Direct Interrogatives

Direct question labels remain preserved as question-ready:

- yes/no direct interrogatives still pass through unchanged
- wh-questions still pass through unchanged

This also preserves 60B.20-style behaviour.

## Focused Test Result

Command run:

```bash
npx vitest run tests/graph/question-formulator.test.js
```

Result:

```text
PASS (29/29)
```

Covered regressions:

1. Exact 60B.24 rationale stripping regression
2. Clean `whether...` proposition without rationale
3. Direct interrogative preserved
4. Wh-question preserved
5. Source node description unchanged
6. Non-`whether` semicolon content not globally truncated

## What Remains Unproven Until Live 60B.24 Rerun

This experiment proves the deterministic question-formulation layer behaves correctly for the fixed regression shape and focused test coverage.

Still unproven live:

- the exact end-to-end 60B.24 continuation through the full runtime path
- whether any upstream live-model variation changes the selected unknown or surrounding graph state before formulation

## Production Boundary Confirmed

Changed:

- `lib/graph/question-formulator.js`
- `tests/graph/question-formulator.test.js`

Not changed:

- prompt builder
- schema
- apply-proposal
- question-target selection
- materiality
- reasoning-context compatibility
- provider integration
- harness