# Lookback: PR #839 Foundational Family Specification Appendices

**Date:** 2026-06-20  
**PR:** #839  
**Status:** Completed (Docs-only)  

## Objectives & Context

Following the merge of **ADR-0224**, this PR establishes the controlled, constitutional location for foundational substrate family specifications. ADR-0224 mandates that:
1. No family may receive implementation slices before its complete specification is written and approved in the designated location.
2. The substrate must not become benchmark-shaped (e.g., GSM8K-only); it must support minimal reusable constructional affordances across at least 8 foundational elementary/middle-school domains.

This PR executes the first post-ADR-0224 step:
- Created the controlled specification directory `docs/specs/foundational-families/`.
- Established `README.md` and `TEMPLATE.md` to define the gating rules and mandatory specification fields.
- Drafted the initial specification files for two high-leverage families: `quantity-entity-binding.md` and `state-change.md`.

## Architectural Alignment & Verification

This work strictly adheres to the semantic-substrate affordance audit charter (**ADR-0223**) and readiness mapping rules (**ADR-0224**). 

- **Docs-Only Scope:** No codebase changes or executable files were created or modified. All changes reside strictly under `docs/` and `HANDOFF-gpt55-2026-06-20.md`.
- **Benchmark Autonomy:** The specifications explicitly decouple the substrate definitions from GSM8K, detailing cross-domain examples in physical sciences, reading comprehension, life sciences, and social studies.
- **Typed ProblemFrame Focus:** The specifications present the ProblemFrame/domain-frame representations in typed relation/binding language (using Python-like class syntax for `MentionBinding`, `BoundRelation`, `RelationRole`, etc.), rather than prose-only descriptions.
- **No Implementation Authorization:** Both specifications carry explicit serving status notes and clear warnings that implementation is unauthorized by this PR and must come via separate, evidence-backed PRs.

## Invariant Review

- **Versor Condition:** `||F * reverse(F) - 1||_F < 1e-6` is trivially preserved as no algebra, field, or solver code was touched.
- **No New Legacy:** No local parsing logic or regex was added, satisfying the deprecation rules.
- **Wrong-Zero Discipline:** Retained.
