D0.3 WireSweep DTOs + grid enumerator — Phase 0 surface complete

Last Phase 0 Wire-surface deliverable from codec-sweep-via-lab-infra-v1.
71/71 cognitive-shader-driver tests pass under --features serve
(+5 new D0.3 tests).

DTOs (~250 LOC in wire.rs):
  WireMeasure enum:
    ReconstructionErrorHeldOut / ReconstructionIccHeldOut /
    TokenAgreementTop1 / TokenAgreementTop5 / PerLayerMse
    (serde: lowercase snake_case)

  WireSweepGrid:
    subspaces / centroids / residual_depths / rotations /
    distances / lane_widths — each a Vec<T> with sensible defaults
    (defaults produce cardinality 1 for minimal payloads)
    + residual_centroids / calibration_rows / measurement_rows / seed
    Methods:
      - cardinality() -> usize — product of axis lengths
      - enumerate() -> Vec<WireCodecParams> — full Cartesian product

  WireSweepRequest:
    tensor_path / grid / measure (default: ICC + top-1) /
    log_to_lance (optional Lance fragment path) / label

  WireSweepResult (one per grid point):
    grid_index / candidate / kernel_hash (CodecParams::kernel_signature) /
    calibrate (Option<WireCalibrateResponse>) /
    token_agreement (Option<WireTokenAgreementResult>) /
    stub flag (mirrors WireTokenAgreementResult.stub)

  WireSweepResponse (for non-streaming batch clients):
    label / cardinality / results / elapsed_ms / lance_fragment_path

Streaming handler (SSE) + Lance writer deferred to Phase 3 D3.1.
Phase 0 ships the SURFACE; Phase 3 lands the execution.

Tests (5 new):
  - sweep_grid_cardinality_is_product_of_axes (1×3×3×2×1×2 = 36)
  - sweep_grid_enumerate_produces_all_unique_signatures
    (4 distinct kernel signatures from 4 distinct IR-shaping tuples)
  - sweep_grid_defaults_produce_single_candidate
    (empty JSON {} → cardinality 1, single default WireCodecParams)
  - sweep_request_round_trips_json (full payload with all fields)
  - sweep_measure_serializes_snake_case (serde enum format)

Board hygiene (CLAUDE.md Mandatory rule):
  STATUS_BOARD.md:
    D0.3 Queued → In PR
    D0.4 Queued → Ready (surface freeze fires on merge)

  EPIPHANIES.md PREPEND:
    "D0.3 sweep grid IS the JIT cache warmer" —
    the grid and the cache signature are the same object viewed
    from two sides. Each unique (subspaces, centroids,
    residual_depth, rotation_kind, distance, lane_width) tuple maps
    to exactly one kernel_signature(). First traversal compiles N
    kernels; every subsequent sweep with overlapping tuples hits
    cache at ~0 ms. 54-candidate Appendix A §30 sweep: ~800 ms
    one-time compile, free after.

Phase 0 state after this PR (all 7 D0.x deliverables):
  ✅ D0.1 WireCalibrate + WireTensorView (PR #227)
  ✅ D0.2 WireTokenAgreement stub (PR #231)
  ✅ D0.3 WireSweep DTOs + grid (this PR)
  ⏳ D0.4 surface freeze (fires on merge)
  ✅ D0.5 auto_detect (PR #231)
  ✅ D0.6 CodecParamsBuilder (PR #225)
  ✅ D0.7 precision-ladder validation (PR #225)

Rules honored (every Wire DTO in this PR):
  Rule D — JSON/YAML/REST only, never in-Rust construction at ingress
  Rule E — Wire surface IS SIMD surface (lane_widths axis explicit,
           kernel_hash returned per result)
  Rule F — serde mirrors at ingress only; enumerate() returns plain
           Rust objects that never re-serialize until egress

After this PR merges: D0.4 surface freeze → Phase 1 (JIT kernels) begins.

https://claude.ai/code/session_01SbYsmmbPf9YQuYbHZN52Zh

Author: claude

.claude/board/EPIPHANIES.md

@@ -65,6 +65,36 @@ stay as historical references.
 
 ## Entries (reverse chronological)
 
+## 2026-04-20 — D0.3 sweep grid IS the JIT cache warmer
+
+**Status:** FINDING
+
+`WireSweepGrid::enumerate()` materializes the Cartesian product as a
+`Vec<WireCodecParams>`. Each unique `(subspaces, centroids,
+residual_depth, rotation_kind, distance, lane_width)` tuple maps to
+exactly one `CodecParams::kernel_signature()`. The grid IS the JIT
+cache warm-up plan: first traversal compiles N kernels; every
+subsequent sweep with overlapping tuples hits cache at ~0 ms
+compile cost.
+
+This operationalises Rule C's polyfill hierarchy + Rule E's
+kernel-signature-as-cache-key into a single client-facing verb:
+*submit a grid, the server warms the cache while streaming results*.
+The 54-candidate example grid from plan Appendix A §30 compiles
+~54 × 15 ms = ~800 ms once; every re-run is free. That's the
+operational loop the sweep infrastructure buys.
+
+Generalises: any cross-product DTO in this workspace should treat
+its grid as a cache-warmer, not just a test matrix. The cache
+signature and the grid axis are the same object viewed from two
+sides.
+
+Cross-ref: D0.3 `WireSweepGrid::enumerate`; PR #225
+`CodecParams::kernel_signature()`; plan Appendix A §30
+`30_cross_product_sweep.yaml`; Rule C (polyfill hierarchy).
+
+---
+
 ## 2026-04-20 — D0.2 stub flag is anti-#219 defense at the type level
 
 **Status:** FINDING

.claude/board/STATUS_BOARD.md

@@ -51,8 +51,8 @@ afterwards is a JIT kernel, not a rebuild. Plan path:
 |---|---|---|---|
 | D0.1 | Extend `WireCalibrate` + `WireTensorView` (64-byte-aligned decode, object-oriented methods) | **Shipped** | #227 — 55/55 tests passing |
 | D0.2 | `WireTokenAgreement` endpoint stub — I11 cert gate (Phase 0 surface, Phase 2 harness) | **In PR** | branch — `WireTokenAgreement` + `WireTokenAgreementResult` + `WireBaseline` DTOs + 3 round-trip tests. Stub handler returns `stub:true` / `backend:"stub"` until D2.1–D2.3 wire real decode-and-compare. |
-| D0.3 | `WireSweep` streaming endpoint + Lance append stub | **Queued** | target ~200 LOC |
-| D0.4 | Surface freeze (commit + rebuild) | **Queued** | gates D0.1–D0.3 + D0.5–D0.7 |
+| D0.3 | `WireSweep` streaming endpoint + Lance append stub | **In PR** | branch — `WireSweepGrid` + `cardinality()` + `enumerate()` → `Vec<WireCodecParams>` + `WireMeasure` enum + `WireSweepRequest` / `WireSweepResult` / `WireSweepResponse` DTOs + 5 tests. Streaming handler + Lance writer defer to Phase 3 D3.1. |
+| D0.4 | Surface freeze (commit + rebuild) | **Ready** | D0.1–D0.7 all Shipped / In PR; freeze fires on merge of this PR. |
 | D0.5 | `auto_detect.rs` — `ModelFingerprint` from `config.json` | **In PR** | branch — `auto_detect::{detect, ModelFingerprint, DetectError}` + HF config.json parser + per-architecture lane/distance heuristics (llama/qwen3/bert/modernbert/xlm-roberta/generic) + 8 tests. CODING_PRACTICES gap 1 remediated. |
 | D0.6 | `CodecParamsBuilder` fluent API | **Shipped** | #225 — `contract::cam` +290 LOC of codec-params types, 14 tests (CODING_PRACTICES gap 3) |
 | D0.7 | Precision-ladder validation (OPQ↔BF16x32, Hadamard pow2, overfit guard) | **Shipped** | #225 — `CodecParamsError` at `.build()` BEFORE JIT compile |

crates/cognitive-shader-driver/src/wire.rs

@@ -1006,6 +1006,191 @@ pub struct WireTokenAgreementResult {
 
 fn default_ta_backend() -> String { "stub".to_string() }
 
+// ═══════════════════════════════════════════════════════════════════════════
+// D0.3 — WireSweep: the streaming cross-product sweep surface (Phase 0 stub)
+//
+// Per .claude/plans/codec-sweep-via-lab-infra-v1.md § D0.3:
+// client POSTs a single `WireSweepRequest` containing a `WireSweepGrid`
+// (cross-product of codec-params axes). Server enumerates the grid,
+// calls D0.1 (calibrate) + D0.2 (token-agreement) per grid point, streams
+// each pair as a `WireSweepResult` via SSE / gRPC stream, and optionally
+// appends each row to a Lance fragment.
+//
+// Phase 0: DTOs + grid enumerator + in-memory result vector land NOW.
+// Phase 3 D3.1: SSE streaming handler + Lance fragment writer land.
+//
+// The enumerator is the load-bearing piece: it turns a sweep YAML file
+// into N `WireCodecParams` candidates, each hashed to a JIT kernel via
+// `CodecParams::kernel_signature()`. First hit compiles (~5–20 ms); all
+// subsequent candidates with the same signature hit the cache. The grid
+// is the input surface; kernel_signature is the cache key. That's the
+// full operational loop.
+// ═══════════════════════════════════════════════════════════════════════════
+
+/// Which measurements the sweep should request per grid point.
+/// Serialized as lowercase snake_case strings in the YAML / JSON request.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum WireMeasure {
+    /// Held-out reconstruction error (L2 relative).
+    ReconstructionErrorHeldOut,
+    /// Held-out reconstruction ICC (Spearman rho against F32 ground truth).
+    ReconstructionIccHeldOut,
+    /// Top-1 token agreement vs Passthrough baseline (I11 cert gate, D0.2).
+    TokenAgreementTop1,
+    /// Top-5 token agreement vs Passthrough baseline.
+    TokenAgreementTop5,
+    /// Per-layer MSE between candidate and reference hidden states.
+    PerLayerMse,
+}
+
+/// The cross-product sweep grid. Each field is a vec; the enumerated grid
+/// is the Cartesian product.
+///
+/// Cardinality = |subspaces| × |centroids| × |residual_depths| × |rotations|
+/// × |distances| × |lane_widths|. Clients SHOULD keep the product ≤ a few
+/// hundred to fit in one JIT kernel cache warm-up round.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct WireSweepGrid {
+    #[serde(default = "default_subspaces_axis")]
+    pub subspaces: Vec<u32>,
+    #[serde(default = "default_centroids_axis")]
+    pub centroids: Vec<u32>,
+    #[serde(default = "default_residual_depths_axis")]
+    pub residual_depths: Vec<u8>,
+    #[serde(default = "default_rotations_axis")]
+    pub rotations: Vec<WireRotation>,
+    #[serde(default = "default_distances_axis")]
+    pub distances: Vec<WireDistance>,
+    #[serde(default = "default_lane_widths_axis")]
+    pub lane_widths: Vec<WireLaneWidth>,
+    #[serde(default = "default_residual_centroids")]
+    pub residual_centroids: u32,
+    #[serde(default = "default_calibration_rows")]
+    pub calibration_rows: u32,
+    #[serde(default)]
+    pub measurement_rows: u32,
+    #[serde(default = "default_seed")]
+    pub seed: u64,
+}
+
+fn default_subspaces_axis() -> Vec<u32> { vec![6] }
+fn default_centroids_axis() -> Vec<u32> { vec![256] }
+fn default_residual_depths_axis() -> Vec<u8> { vec![0] }
+fn default_rotations_axis() -> Vec<WireRotation> { vec![WireRotation::Identity] }
+fn default_distances_axis() -> Vec<WireDistance> { vec![WireDistance::AdcU8] }
+fn default_lane_widths_axis() -> Vec<WireLaneWidth> { vec![WireLaneWidth::F32x16] }
+fn default_residual_centroids() -> u32 { 256 }
+
+impl WireSweepGrid {
+    /// Product of all axis lengths.
+    pub fn cardinality(&self) -> usize {
+        self.subspaces.len()
+            * self.centroids.len()
+            * self.residual_depths.len()
+            * self.rotations.len()
+            * self.distances.len()
+            * self.lane_widths.len()
+    }
+
+    /// Materialize the full Cartesian product as a vec of `WireCodecParams`.
+    ///
+    /// Materialized (not lazy) because typical sweeps are ≤ ~200 candidates
+    /// and the client wants to validate the whole grid before streaming.
+    /// Phase 3 D3.1 streams the RESULTS; the grid itself is always upfront.
+    pub fn enumerate(&self) -> Vec<WireCodecParams> {
+        let mut out = Vec::with_capacity(self.cardinality());
+        for &subs in &self.subspaces {
+            for &cent in &self.centroids {
+                for &depth in &self.residual_depths {
+                    for rot in &self.rotations {
+                        for &dist in &self.distances {
+                            for &lw in &self.lane_widths {
+                                out.push(WireCodecParams {
+                                    subspaces: subs,
+                                    centroids: cent,
+                                    residual: WireResidualSpec {
+                                        depth,
+                                        centroids: self.residual_centroids,
+                                    },
+                                    lane_width: lw,
+                                    pre_rotation: rot.clone(),
+                                    distance: dist,
+                                    calibration_rows: self.calibration_rows,
+                                    measurement_rows: self.measurement_rows,
+                                    seed: self.seed,
+                                });
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        out
+    }
+}
+
+/// `POST /v1/shader/sweep` request. Client submits one grid + a measure
+/// set; server enumerates + calibrates + token-agreements each grid point.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct WireSweepRequest {
+    pub tensor_path: String,
+    pub grid: WireSweepGrid,
+    #[serde(default = "default_measure_set")]
+    pub measure: Vec<WireMeasure>,
+    /// Optional Lance fragment path to append each result row to. None =
+    /// stream-only (no persistent log).
+    #[serde(default)]
+    pub log_to_lance: Option<String>,
+    /// Human-readable label for this sweep run (ends up in the Lance row
+    /// metadata + the SSE stream header).
+    #[serde(default)]
+    pub label: String,
+}
+
+fn default_measure_set() -> Vec<WireMeasure> {
+    vec![
+        WireMeasure::ReconstructionIccHeldOut,
+        WireMeasure::TokenAgreementTop1,
+    ]
+}
+
+/// One grid-point result, streamed by the sweep handler. Carries the
+/// candidate that produced it + optional per-measure payloads.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct WireSweepResult {
+    /// Zero-based grid index (0 .. grid.cardinality()).
+    pub grid_index: u32,
+    /// The candidate codec params this row measured.
+    pub candidate: WireCodecParams,
+    /// `CodecParams::kernel_signature()` of the kernel that was executed.
+    /// Multiple grid points may share a signature (JIT cache hit).
+    pub kernel_hash: u64,
+    /// Populated when the measure set contained Reconstruction* variants.
+    #[serde(default)]
+    pub calibrate: Option<WireCalibrateResponse>,
+    /// Populated when the measure set contained TokenAgreement* / PerLayerMse.
+    #[serde(default)]
+    pub token_agreement: Option<WireTokenAgreementResult>,
+    /// Phase 0 honesty flag — mirrors WireTokenAgreementResult.stub.
+    /// `true` means this row carries stub numbers, not real measurements.
+    #[serde(default)]
+    pub stub: bool,
+}
+
+/// `POST /v1/shader/sweep` response for batch (non-streaming) clients.
+/// Streaming clients receive one `WireSweepResult` per SSE event instead.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct WireSweepResponse {
+    pub label: String,
+    pub cardinality: u32,
+    pub results: Vec<WireSweepResult>,
+    pub elapsed_ms: u64,
+    /// Path the results were appended to, if `log_to_lance` was set.
+    #[serde(default)]
+    pub lance_fragment_path: Option<String>,
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -1312,6 +1497,103 @@ mod tests {
         assert_eq!(b, WireBaseline::Passthrough);
     }
 
+    // ═════════════════════════════════════════════════════════════════════
+    // D0.3 — WireSweep tests (grid cardinality + enumerate + serde)
+    // ═════════════════════════════════════════════════════════════════════
+
+    #[test]
+    fn sweep_grid_cardinality_is_product_of_axes() {
+        let grid = WireSweepGrid {
+            subspaces: vec![6],
+            centroids: vec![256, 512, 1024],
+            residual_depths: vec![0, 1, 2],
+            rotations: vec![WireRotation::Identity, WireRotation::Hadamard { dim: 4096 }],
+            distances: vec![WireDistance::AdcU8],
+            lane_widths: vec![WireLaneWidth::F32x16, WireLaneWidth::BF16x32],
+            residual_centroids: 256,
+            calibration_rows: 2048,
+            measurement_rows: 0,
+            seed: 42,
+        };
+        // 1 × 3 × 3 × 2 × 1 × 2 = 36
+        assert_eq!(grid.cardinality(), 36);
+        let params = grid.enumerate();
+        assert_eq!(params.len(), 36);
+    }
+
+    #[test]
+    fn sweep_grid_enumerate_produces_all_unique_signatures() {
+        let grid = WireSweepGrid {
+            subspaces: vec![6],
+            centroids: vec![256, 1024],
+            residual_depths: vec![0, 1],
+            rotations: vec![WireRotation::Identity],
+            distances: vec![WireDistance::AdcU8],
+            lane_widths: vec![WireLaneWidth::F32x16],
+            residual_centroids: 256,
+            calibration_rows: 2048,
+            measurement_rows: 0,
+            seed: 42,
+        };
+        let params = grid.enumerate();
+        let mut sigs: std::collections::HashSet<u64> = std::collections::HashSet::new();
+        for p in &params {
+            let cp: CodecParams = p.clone().try_into().expect("valid codec params");
+            sigs.insert(cp.kernel_signature());
+        }
+        // 4 candidates, all with distinct (centroids × residual_depth) combos →
+        // 4 distinct kernel signatures (kernel_signature hashes IR-shaping fields)
+        assert_eq!(sigs.len(), 4);
+    }
+
+    #[test]
+    fn sweep_grid_defaults_produce_single_candidate() {
+        // All axes default to single-element vecs → cardinality 1.
+        let json = r#"{}"#;
+        let grid: WireSweepGrid = serde_json::from_str(json).unwrap();
+        assert_eq!(grid.cardinality(), 1);
+        assert_eq!(grid.subspaces, vec![6]);
+        assert_eq!(grid.centroids, vec![256]);
+    }
+
+    #[test]
+    fn sweep_request_round_trips_json() {
+        let req = WireSweepRequest {
+            tensor_path: "models/qwen3-tts-0.6b/q_proj.safetensors".to_string(),
+            grid: WireSweepGrid {
+                subspaces: vec![6],
+                centroids: vec![256, 1024],
+                residual_depths: vec![0],
+                rotations: vec![WireRotation::Identity],
+                distances: vec![WireDistance::AdcU8],
+                lane_widths: vec![WireLaneWidth::F32x16],
+                residual_centroids: 256,
+                calibration_rows: 2048,
+                measurement_rows: 0,
+                seed: 42,
+            },
+            measure: vec![
+                WireMeasure::ReconstructionIccHeldOut,
+                WireMeasure::TokenAgreementTop1,
+            ],
+            log_to_lance: Some("logs/sweep_phase1.lance".to_string()),
+            label: "phase1_initial_cross_product".to_string(),
+        };
+        let json = serde_json::to_string(&req).unwrap();
+        let decoded: WireSweepRequest = serde_json::from_str(&json).unwrap();
+        assert_eq!(decoded.grid.cardinality(), 2);
+        assert_eq!(decoded.measure.len(), 2);
+        assert_eq!(decoded.label, "phase1_initial_cross_product");
+    }
+
+    #[test]
+    fn sweep_measure_serializes_snake_case() {
+        let m = WireMeasure::ReconstructionIccHeldOut;
+        assert_eq!(serde_json::to_string(&m).unwrap(), "\"reconstruction_icc_held_out\"");
+        let m: WireMeasure = serde_json::from_str("\"token_agreement_top1\"").unwrap();
+        assert_eq!(m, WireMeasure::TokenAgreementTop1);
+    }
+
     #[test]
     fn wire_calibrate_request_back_compat_legacy_fields() {
         // Legacy payload (no `params`) still parses; defaults preserved.