Wave-1 PB2: FixedPoint gate #16 (pb_self_compile_fixed_point R3 horizon) — brief r3-wave1-pb2-fixedpoint-gate16-r3-horizon-worker.md

.github/workflows/ci.yml

@@ -587,6 +587,11 @@ jobs:
 
   # DB-8 — fixed-point ratchet infrastructure (Lane 3 Stage 3c prep). Staged until
   # Lane 1 Stage 1e closes: do not block merges on this job yet.
+  #
+  # R3 T-FixedPoint / `docs/r3-program-plan.md` §1.8 gate #16: `self_host_fixed_point`
+  # is the DB-8 mechanical verifier on the path to the strong fixed-point horizon;
+  # R1 `pb_self_compile_fixed_point` pass/fail still comes from `verification.dag` +
+  # `test_runner` — this job's continue-on-error posture does not redefine that gate.
   self_host_ratchet:
     # Always schedule this job name on PRs so branch-protection "required checks" get a
     # definitive **success** after `v3` (skipped jobs / workflow-wide cancels were surfacing

docs/db-history/db-8.md

@@ -8,3 +8,7 @@ Collected receipts and reconciliation notes moved out of [ROADMAP.md](../../ROAD
 - **CI binary:** `cargo run -p v3-compiler --bin self_host_fixed_point` — proves pipeline snapshot fixed-point on `default_fixed_point_source`, probes `dsl/gunbc/compiler.dag`, writes `target/self_host/receipt.json`. Full emit→rustc→run→diff cycle stays **staged** until `compiler.dag` parses under v3 and emitted output is a CLI that can re-emit (see phase-plan §6 answers).
 - **Invariant:** `INVARIANTS.md` §Deterministic emission (D-1); `emit.rs` module docs cite D-1 (`feedback_substrate_principle_audit` Q5 — single authority for determinism invariants).
 - **Substrate-readiness (phase-plan §6 checklist):** tracked in [`docs/phase-plan-2026-04-18.md`](docs/phase-plan-2026-04-18.md) §6 — rows still 🟡/❌ remain upstream deferrals (1e, 1c Python tail, 2b workflow consumer, 2c runner, 2d, 3b) with dissolution triggers in ROADMAP; no new orphan debt from this audit.
+
+### R3 T-FixedPoint — §1.8 gate #16 (`pb_self_compile_fixed_point` R3 horizon)
+
+The R1 lane gate and R3 thesis facet 2 share the **predicate name** but not the acceptance bar — see [`docs/r3-structure.md`](../r3-structure.md) §"T-FixedPoint" and [`docs/r2-structure.md`](../r2-structure.md) (R1 closure criteria). This DB-8 stack (`self_host_fixed_point`, `determinism_test`, receipt contract) is the **mechanical ratchet** aligned with [`docs/design-fixed-point-ratchet.md`](../design-fixed-point-ratchet.md); the future strong `.dag` suite (`pb_self_compile_fixed_point_strong`, Row A/B/C per [`docs/briefs/r3-pb-t-fixedpoint-worker.md`](../briefs/r3-pb-t-fixedpoint-worker.md)) is **dispatch-gated** and must not be authored in `verification.dag` until joint preconditions in that brief read green. Wave-1 P0 worker brief: [`docs/briefs/r3-wave1-pb2-fixedpoint-gate16-r3-horizon-worker.md`](../briefs/r3-wave1-pb2-fixedpoint-gate16-r3-horizon-worker.md).

src/v3/compiler/src/bin/self_host_fixed_point.rs

@@ -1,5 +1,13 @@
 //! DB-8 — fixed-point ratchet driver (`docs/design-fixed-point-ratchet.md`).
 //!
+//! **R3 cross-read (P0 pin, no new pass/fail):** R3 program-plan §1.8 gate **#16**
+//! (`pb_self_compile_fixed_point`, T-FixedPoint) has a **strong** thesis horizon
+//! distinct from the R1 `verification.dag` claim of the same name — see
+//! `docs/r3-structure.md` §"T-FixedPoint" (two-horizon framing),
+//! `docs/briefs/r3-pb-t-fixedpoint-worker.md` (dispatch preconditions; future
+//! `pb_self_compile_fixed_point_strong`), and `docs/briefs/r3-wave1-pb2-fixedpoint-gate16-r3-horizon-worker.md`.
+//! History and CI posture for this binary: `docs/db-history/db-8.md`.
+//!
 //! Full cycle (emit → `rustc` → run → byte-diff) requires a v3-parseable
 //! `dsl/gunbc/compiler.dag` **and** an emitted CLI that can re-run emission on
 //! that file. Until Lane 3 Stage 3c, `compiler.dag` is a cycle meta-model that