docs/briefs/ADR-0241-chiral-spinor-brief.md

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+# Brief: ADR-0241 Non-Vacuous Chiral Spinor Charge (P8)
+
+**For:** Antigravity / Gemini design + TDD  
+**Status:** STOP POINT after P7 demotion  
+**Branch:** `feat/adr-0241-0242-implementation` (PR #37)
+
+---
+
+## Takeoff
+
+```bash
+git fetch forgejo
+git checkout feat/adr-0241-0242-implementation
+git pull forgejo feat/adr-0241-0242-implementation
+```
+
+Read:
+
+1. `AGENTS.md`
+2. `docs/adr/ADR-0241-...md` (chiral charge row; #19 retirement)
+3. `docs/research/third-door-blueprint-fidelity.md` W4 / #19 section
+4. `core/physics/wave_manifold.py` — `chiral_charge`, `left_spinor_step`
+5. `docs/briefs/P7_design_note.md` (honesty doctrine — do not invent theater)
+
+---
+
+## Problem
+
+ADR claims non-vacuous \(\mathcal{Q}=\langle\psi I_5\widetilde{\psi}\rangle_0\).  
+Today `chiral_charge` is **honest structural ~0** on real Cl(4,1) (even product × central \(I_5\) has no grade-0 for the #19 family). Tests lock conservation of ~0 and even-versor honesty.
+
+P8 goal: either (A) a **non-vacuous spinor path** with informative conserved Q, without reviving vacuous #19 gate on even unit versors; or (B) **permanent demotion** of non-vacuous claim with ADR language + fidelity ⚪ RETIRED, if design proves impossible under real Cl(4,1) without complex/pair structure.
+
+---
+
+## Hard constraints
+
+- Must **not** revive grade-5 gate on even unit versors (#19)
+- Even field-state path stays honest (~0 or N/A)
+- Spinor / odd-capable path: if non-vacuous, Q informative + conserved under left unitary \(R\)
+- Algebra-native; no hot-path unitize; off-serve
+- Prefer fail-closed / honest demotion over fake non-zero Q
+
+## Design options to evaluate (pick one with proof sketch)
+
+1. Pair-spinor / complex structure via central \(I_5\) as algebraic \(i\)
+2. Even/odd split with grade-sensitive charge
+3. Two-component left ideals in Cl(4,1)
+4. Permanent demotion (document why real Cl(4,1) cannot host non-vacuous Q)
+
+## RED tests (if implementing non-vacuous)
+
+```text
+test_chiral_charge_nonzero_on_designed_spinor_packet
+test_chiral_charge_conserved_under_left_unitary_R
+test_chiral_charge_still_honest_zero_on_even_unit_versor
+test_goldtether_chiral_term_only_when_informative
+```
+
+If demoting: one behavioral pin that documents structural vacuity remains and ADR/fidelity language is honest.
+
+## Out of scope
+
+P9 contemplation seam, Rust, serve wiring, re-opening retired multi-grade analytic polar (P7).
+
+## Success
+
+Non-vacuous spinor Q **or** honest permanent demotion; W4 fidelity flipped under honest criterion; PR #37 updated on Forgejo.