R2 PB

docs/briefs/r2-substrate-manager.md

@@ -35,7 +35,7 @@ Substrate primitive landing for `Lens<C>` per the 8-question dialogue (Q6/Q7/Q8
 ```
 Lens<C> = (
   name: String,
-  read: (Dag, Behavior) → Witness<C>,        // Q6: Witness<C> stays as-is; Diagnostic.kind extends for structural failures
+  read: (Dag, Behavior) → Witness<C>,        // Q6: Witness<C> stays as-is; structural failures use lens-owned Diagnostic.kind declarations
   sequential: Monoid<C>,                       // structural inhabitance; replaces parallel compose+unit cascade
   branch: (C, C) → C,
   iterate: (LoopBound, C) → C,

docs/r2-structure.md

@@ -403,7 +403,7 @@ Three additional items the Director review identified as R2-expansion (not R3):
 
 **Authority docs** for the dialogue (DECISION-locked paragraphs):
 - Q1–Q5 (T-Ground / cross-target modeling): [`docs/design-emission-model.md`](design-emission-model.md) §"Design questions to surface and lock before dispatch"
-- Q6–Q8 (lens-framework spec semantics): [`docs/design-lens-framework.md`](design-lens-framework.md) §"Design questions to lock before substrate dispatch"
+- Q6–Q8 (lens-framework spec semantics, including Q6's `Diagnostic.kind` extensibility protocol): [`docs/design-lens-framework.md`](design-lens-framework.md) §"Design questions to lock before substrate dispatch"
 
 **Meta-deliverable:** the modeling pattern that surfaced across Q1/Q2/Q3 (find shared parent → distinguish coproducts from coordinates → classify primitive vs lens-extensible) was promoted to [`INVARIANTS.md`](../INVARIANTS.md) §P1 as the "Substrate-fact introduction procedure" — a 3-step decision procedure workers can self-serve when introducing new substrate facts.