diff --git a/prod/clean_arch/violet/__init__.py b/prod/clean_arch/violet/__init__.py
new file mode 100644
index 0000000..0976aa0
--- /dev/null
+++ b/prod/clean_arch/violet/__init__.py
@@ -0,0 +1,11 @@
+"""VIOLET — staged rebuild of the PINK-on-DITAv2 runtime.
+
+Stage V0: reactor clock primitives + latency harness (this package).
+Stage V1: observe-only runtime scaffolding (observe_guard, divergence).
+
+Charter: violet-subsecond-rebuild-plan (operator memory) — VIOLET is the
+highest-frequency color in the visible spectrum; the runtime is the
+fastest-cadence member of the BLUE/PINK family. The DITAv2 kernel, exec
+router, venue adapters and persistence are SHARED LIBRARIES; only
+launcher/identity/namespaces fork.
+"""
diff --git a/prod/clean_arch/violet/clock.py b/prod/clean_arch/violet/clock.py
new file mode 100644
index 0000000..d94d960
--- /dev/null
+++ b/prod/clean_arch/violet/clock.py
@@ -0,0 +1,321 @@
+"""VIOLET reactor clock primitives (Stage V0).
+
+NOT a metronome. The system "clock" is:
+  - ONE monotonic timebase (``mono_ns``) stamped on every event;
+  - per-plane sequence clocks (``PlaneClock``) with staleness budgets —
+    each data plane (scan ~5-6 s, venue push ~ms, account events) advances
+    at its own rate and is judged stale against its own budget;
+  - a deadline scheduler (``DeadlineScheduler``) for genuinely time-based
+    work (router TTLs, SL guards): a timer heap driven by ONE coroutine,
+    woken EARLY via asyncio.Event when an earlier deadline is inserted —
+    the early-wake, not the tick, is what keeps jitter inside budget.
+
+Latency accounting uses ``LatencyHistogram``: raw reservoir samples with
+exact order-statistic percentiles (no bucket interpolation) so the V0 gate
+numbers are not artifacts of bucketing.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import heapq
+import json
+import time
+from dataclasses import dataclass, field
+from typing import Any, Callable, Dict, List, Optional
+
+
+def mono_ns() -> int:
+    """The single VIOLET timebase. Wall-clock is for report metadata only."""
+    return time.monotonic_ns()
+
+
+# ── Latency accounting ───────────────────────────────────────────────────────
+
+
+class LatencyHistogram:
+    """Raw-reservoir latency recorder with exact percentiles.
+
+    Keeps up to ``reservoir`` raw samples (first-N retention: V0 storms are
+    sized below the reservoir so retention is total; the cap only guards
+    memory if a harness is misconfigured). Percentiles are exact order
+    statistics over the retained samples.
+    """
+
+    def __init__(self, name: str, *, reservoir: int = 200_000) -> None:
+        self.name = name
+        self.reservoir = int(reservoir)
+        self._samples: List[int] = []
+        self._overflow = 0
+        self._max_ns = 0
+        self._min_ns: Optional[int] = None
+
+    def record(self, dt_ns: int) -> None:
+        dt = int(dt_ns)
+        if dt > self._max_ns:
+            self._max_ns = dt
+        if self._min_ns is None or dt < self._min_ns:
+            self._min_ns = dt
+        if len(self._samples) < self.reservoir:
+            self._samples.append(dt)
+        else:
+            self._overflow += 1
+
+    @property
+    def count(self) -> int:
+        return len(self._samples) + self._overflow
+
+    def percentile_ns(self, p: float) -> int:
+        """Exact order statistic (nearest-rank) over retained samples.
+
+        nearest-rank: the smallest value whose cumulative fraction >= p,
+        i.e. rank = ceil(p * n). (round(p*n + 0.5) is WRONG: banker's
+        rounding makes round(5.5) == 6, shifting p50 of 1..10 to 6.)
+        """
+        if not self._samples:
+            return 0
+        ordered = sorted(self._samples)
+        import math as _math
+
+        rank = max(1, min(len(ordered), _math.ceil(p * len(ordered))))
+        return ordered[rank - 1]
+
+    def to_dict(self) -> Dict[str, Any]:
+        ms = 1e-6
+        return {
+            "name": self.name,
+            "count": self.count,
+            "retained": len(self._samples),
+            "overflow_dropped": self._overflow,
+            "min_ms": (self._min_ns or 0) * ms,
+            "p50_ms": self.percentile_ns(0.50) * ms,
+            "p90_ms": self.percentile_ns(0.90) * ms,
+            "p99_ms": self.percentile_ns(0.99) * ms,
+            "p999_ms": self.percentile_ns(0.999) * ms,
+            "max_ms": self._max_ns * ms,
+        }
+
+    def report(self) -> str:
+        d = self.to_dict()
+        return (
+            f"{d['name']:<24} n={d['count']:<8} "
+            f"p50={d['p50_ms']:8.3f}ms p90={d['p90_ms']:8.3f}ms "
+            f"p99={d['p99_ms']:8.3f}ms p99.9={d['p999_ms']:8.3f}ms "
+            f"max={d['max_ms']:8.3f}ms"
+        )
+
+
+# ── Plane clocks ─────────────────────────────────────────────────────────────
+
+
+# Default staleness budgets (ns). Scan budget = two missed 6 s scans; venue
+# budget = 2 s without any push while connected; account = 5 s. These are
+# LABELS for health logic — never data cadences (operator rule: cadences are
+# sacred; staleness thresholds are tunable).
+SCAN_STALENESS_NS = 12_000_000_000
+VENUE_STALENESS_NS = 2_000_000_000
+ACCOUNT_STALENESS_NS = 5_000_000_000
+
+
+@dataclass
+class PlaneClock:
+    """Sequence clock for one data plane.
+
+    ``seq`` increments on every observed plane event; ``last_mono_ns`` stamps
+    it on the shared timebase. ``is_stale`` is strict (> budget): an age
+    exactly equal to the budget is NOT stale, so a budget chosen as an exact
+    multiple of the plane's natural cadence does not flap on-cycle (the MHS
+    FIX-9 lesson: a threshold equal to the writer's refresh period is stale
+    by construction).
+    """
+
+    name: str
+    staleness_budget_ns: int
+    seq: int = 0
+    last_mono_ns: int = -1
+
+    def tick(self, now_ns: Optional[int] = None) -> int:
+        self.seq += 1
+        self.last_mono_ns = mono_ns() if now_ns is None else int(now_ns)
+        return self.seq
+
+    def age_ns(self, now_ns: Optional[int] = None) -> int:
+        """Nanoseconds since last tick; -1 if the plane has never ticked."""
+        if self.last_mono_ns < 0:
+            return -1
+        now = mono_ns() if now_ns is None else int(now_ns)
+        return max(0, now - self.last_mono_ns)
+
+    def is_stale(self, now_ns: Optional[int] = None) -> bool:
+        """True when the plane has ticked at least once AND age > budget.
+
+        A never-ticked plane is 'not yet alive', a different condition from
+        'went stale' — callers gate startup on seq > 0 separately.
+        """
+        age = self.age_ns(now_ns)
+        return age > self.staleness_budget_ns if age >= 0 else False
+
+    def snapshot(self) -> Dict[str, Any]:
+        return {
+            "name": self.name,
+            "seq": self.seq,
+            "last_mono_ns": self.last_mono_ns,
+            "age_ns": self.age_ns(),
+            "stale": self.is_stale(),
+            "budget_ns": self.staleness_budget_ns,
+        }
+
+
+# ── Deadline scheduler ───────────────────────────────────────────────────────
+
+
+class Deadline:
+    """Handle for a scheduled deadline. ``cancel()`` is idempotent."""
+
+    __slots__ = ("due_mono_ns", "name", "_cancelled", "_fired")
+
+    def __init__(self, due_mono_ns: int, name: str = "") -> None:
+        self.due_mono_ns = int(due_mono_ns)
+        self.name = name
+        self._cancelled = False
+        self._fired = False
+
+    @property
+    def cancelled(self) -> bool:
+        return self._cancelled
+
+    @property
+    def fired(self) -> bool:
+        return self._fired
+
+    def cancel(self) -> None:
+        self._cancelled = True
+
+
+class DeadlineScheduler:
+    """Single-driver asyncio deadline scheduler.
+
+    One coroutine owns a heapq of ``(due_ns, n, Deadline, callback)``. It
+    sleeps ``min(next_due - now, max_sleep_ms)`` and is woken EARLY through
+    an asyncio.Event whenever a deadline earlier than the current head is
+    inserted — early-wake is the jitter-budget mechanism; the max_sleep tick
+    is only a liveness backstop.
+
+    Callbacks are synchronous and MUST be non-blocking; async work is
+    dispatched by the callback via ``loop.create_task``. A callback
+    exception is isolated (logged via the optional ``on_error`` hook) and
+    never kills the driver.
+    """
+
+    def __init__(
+        self,
+        *,
+        max_sleep_ms: int = 50,
+        jitter_hist: Optional[LatencyHistogram] = None,
+        on_error: Optional[Callable[[Deadline, BaseException], None]] = None,
+    ) -> None:
+        self._max_sleep_s = max(0.001, float(max_sleep_ms) / 1000.0)
+        self.jitter_hist = jitter_hist
+        self._on_error = on_error
+        self._heap: List[tuple] = []
+        self._n = 0
+        self._wake = asyncio.Event()
+        self._task: Optional[asyncio.Task] = None
+        self._stopping = False
+        self.fired_count = 0
+        self.cancelled_count = 0
+
+    # -- scheduling --------------------------------------------------------
+
+    def schedule_at(
+        self, due_mono_ns: int, cb: Callable[[], None], *, name: str = ""
+    ) -> Deadline:
+        dl = Deadline(due_mono_ns, name)
+        self._n += 1
+        earlier_than_head = not self._heap or due_mono_ns < self._heap[0][0]
+        heapq.heappush(self._heap, (int(due_mono_ns), self._n, dl, cb))
+        if earlier_than_head:
+            self._wake.set()  # early-wake the driver for the new head
+        return dl
+
+    def schedule_in(
+        self, delay_ms: float, cb: Callable[[], None], *, name: str = ""
+    ) -> Deadline:
+        return self.schedule_at(
+            mono_ns() + int(float(delay_ms) * 1e6), cb, name=name
+        )
+
+    @property
+    def pending(self) -> int:
+        return sum(1 for _, _, dl, _ in self._heap if not dl.cancelled and not dl.fired)
+
+    # -- driver ------------------------------------------------------------
+
+    def start(self) -> None:
+        if self._task is None or self._task.done():
+            self._stopping = False
+            self._task = asyncio.get_running_loop().create_task(
+                self._run(), name="violet_deadline_driver"
+            )
+
+    async def stop(self) -> None:
+        self._stopping = True
+        self._wake.set()
+        if self._task is not None:
+            try:
+                await self._task
+            except asyncio.CancelledError:
+                pass
+            self._task = None
+
+    async def _run(self) -> None:
+        while not self._stopping:
+            now = mono_ns()
+            # Fire everything due. NEVER fire early: strict due <= now.
+            while self._heap and self._heap[0][0] <= now:
+                _, _, dl, cb = heapq.heappop(self._heap)
+                if dl.cancelled:
+                    self.cancelled_count += 1
+                    continue
+                dl._fired = True
+                self.fired_count += 1
+                if self.jitter_hist is not None:
+                    self.jitter_hist.record(mono_ns() - dl.due_mono_ns)
+                try:
+                    cb()
+                except BaseException as exc:  # noqa: BLE001 — isolate callbacks
+                    if self._on_error is not None:
+                        try:
+                            self._on_error(dl, exc)
+                        except Exception:
+                            pass
+                now = mono_ns()
+            # Sleep until next head or the liveness tick, whichever first;
+            # an earlier insert sets the event and we re-evaluate immediately.
+            if self._heap:
+                delay_s = min(
+                    self._max_sleep_s,
+                    max(0.0, (self._heap[0][0] - now) / 1e9),
+                )
+            else:
+                delay_s = self._max_sleep_s
+            try:
+                await asyncio.wait_for(self._wake.wait(), timeout=delay_s)
+            except asyncio.TimeoutError:
+                pass
+            self._wake.clear()
+
+
+# ── Report bundling helper ───────────────────────────────────────────────────
+
+
+def histograms_report(hists: List[LatencyHistogram]) -> str:
+    return "\n".join(h.report() for h in hists)
+
+
+def histograms_json(hists: List[LatencyHistogram], **meta: Any) -> str:
+    return json.dumps(
+        {"meta": meta, "histograms": {h.name: h.to_dict() for h in hists}},
+        indent=2,
+        default=str,
+    )
diff --git a/prod/clean_arch/violet/conftest.py b/prod/clean_arch/violet/conftest.py
new file mode 100644
index 0000000..9991a52
--- /dev/null
+++ b/prod/clean_arch/violet/conftest.py
@@ -0,0 +1,8 @@
+"""Pytest config for the VIOLET package."""
+
+
+def pytest_configure(config):
+    config.addinivalue_line(
+        "markers",
+        "gate: stage-gate tests (run explicitly on the prod host with -m gate)",
+    )
diff --git a/prod/clean_arch/violet/harness.py b/prod/clean_arch/violet/harness.py
new file mode 100644
index 0000000..457478d
--- /dev/null
+++ b/prod/clean_arch/violet/harness.py
@@ -0,0 +1,421 @@
+"""VIOLET V0 reactor harness — measured latency gate.
+
+Drives the REAL DITAv2 ``ExecutionKernel`` (Rust-backed, MOCK venue bundle)
+through seeded event storms while a ``DeadlineScheduler`` runs concurrently,
+and reports exact-percentile latency histograms.
+
+Measured quantities (single ``mono_ns`` timebase):
+
+- ``venue_event_reaction`` (THE GATED NUMBER): the producer stamps
+  ``inject_mono_ns`` when putting an event on the consumer asyncio.Queue —
+  modeling the WS-reader→reactor hop exactly as the production
+  ``_run_account_stream`` consumes its stream — and the reactor records
+  ``mono_ns() - inject_mono_ns`` AFTER the kernel fold returns. This
+  includes event-loop scheduling: the charter's "event→reaction in-process".
+  Gate: p99 < 10 ms.
+- ``kernel_call``: brackets the kernel FFI call alone (informational).
+- ``deadline_jitter``: ``t_fire − t_due`` per deadline fired during the
+  storm. Gate: p99 < 25 ms, zero early fires.
+
+Determinism: ``random.Random(seed)`` fully determines the event sequence
+(asserted via sequence hash); latencies naturally vary run to run.
+
+CLI:
+    python -m prod.clean_arch.violet.harness \
+        --events 50000 --deadlines 5000 --seed 42 \
+        --out prod/VIOLET_dev/reports/violet_v0_latency_$(date -u +%Y%m%d).json \
+        --gate
+"""
+
+from __future__ import annotations
+
+import argparse
+import asyncio
+import hashlib
+import json
+import platform
+import random
+import sys
+import time
+from dataclasses import dataclass, field
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+from .clock import (
+    DeadlineScheduler,
+    LatencyHistogram,
+    PlaneClock,
+    ACCOUNT_STALENESS_NS,
+    mono_ns,
+)
+
+# Gate thresholds (charter / plan)
+GATE_REACTION_P99_MS = 10.0
+GATE_JITTER_P99_MS = 25.0
+
+
+# ── Storm specification ──────────────────────────────────────────────────────
+
+
+@dataclass
+class StormSpec:
+    n_events: int = 50_000
+    seed: int = 42
+    # Event-kind mix (account-fold path + FSM mark-price path).
+    mix: Dict[str, float] = field(
+        default_factory=lambda: {
+            "ACCOUNT_UPDATE": 0.35,
+            "FILL_SETTLED": 0.25,
+            "PREDICTED_FILL": 0.15,
+            "FUNDING_FEE": 0.05,
+            "MARK_PRICE": 0.20,
+        }
+    )
+    # Arrival shape. The GATE measures reaction latency under REALISTIC load:
+    # PINK's live BingX stream shows fill cascades of ~4-8 events per burst
+    # (PREDICTED_FILL + FILL_SETTLED + ACCOUNT_UPDATE per action) at low
+    # sustained rates. burst_size=8 / 12 ms ≈ 667 events/s offered — still
+    # >10x production sustained rates. Larger bursts measure intra-burst
+    # QUEUEING physics, not reaction (at ~0.33 ms/fold the tail of a
+    # 16-burst waits ~5 ms before its turn; a 32/1ms storm saturates the
+    # queue outright — measured: see archived 2026-06-12 capacity reports).
+    # Use bigger bursts deliberately for capacity exploration, not the gate.
+    arrival: str = "burst"  # uniform | poisson | burst
+    burst_size: int = 8
+    inter_burst_ms: float = 12.0
+    deadlines: int = 5_000
+    deadline_spread_ms: tuple = (10, 2_000)
+    warmup_events: int = 1_000  # excluded from gate percentiles
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "n_events": self.n_events,
+            "seed": self.seed,
+            "mix": dict(self.mix),
+            "arrival": self.arrival,
+            "burst_size": self.burst_size,
+            "inter_burst_ms": self.inter_burst_ms,
+            "deadlines": self.deadlines,
+            "deadline_spread_ms": list(self.deadline_spread_ms),
+            "warmup_events": self.warmup_events,
+        }
+
+
+@dataclass
+class HarnessReport:
+    spec: StormSpec
+    histograms: Dict[str, Dict[str, Any]]
+    gate: Dict[str, Any]
+    passed: bool
+    sequence_hash: str
+    meta: Dict[str, Any]
+
+    def to_json(self) -> str:
+        return json.dumps(
+            {
+                "spec": self.spec.to_dict(),
+                "histograms": self.histograms,
+                "gate": self.gate,
+                "passed": self.passed,
+                "sequence_hash": self.sequence_hash,
+                "meta": self.meta,
+            },
+            indent=2,
+            default=str,
+        )
+
+    def table(self) -> str:
+        lines = [f"VIOLET V0 latency report — passed={self.passed}"]
+        for name, d in self.histograms.items():
+            lines.append(
+                f"  {name:<24} n={d['count']:<8} p50={d['p50_ms']:8.3f}ms "
+                f"p99={d['p99_ms']:8.3f}ms p99.9={d['p999_ms']:8.3f}ms "
+                f"max={d['max_ms']:8.3f}ms"
+            )
+        for k, v in self.gate.items():
+            lines.append(f"  gate.{k}: {v}")
+        return "\n".join(lines)
+
+
+# ── Event generation (seeded, deterministic) ─────────────────────────────────
+
+
+def generate_events(spec: StormSpec) -> List[Dict[str, Any]]:
+    """Deterministic event sequence from the seed. Same seed → same list."""
+    rng = random.Random(spec.seed)
+    kinds = list(spec.mix.keys())
+    weights = [spec.mix[k] for k in kinds]
+    events: List[Dict[str, Any]] = []
+    for i in range(spec.n_events):
+        kind = rng.choices(kinds, weights=weights, k=1)[0]
+        if kind == "ACCOUNT_UPDATE":
+            # Sentinel −1.0: the harness substitutes the kernel's CURRENT
+            # k_capital at fold time so K and E never diverge into a
+            # capital_frozen reconcile ERROR mid-storm. The substitution is
+            # runtime behavior; the generated sequence (and its hash) stays
+            # fully seed-deterministic.
+            ev = {
+                "kind": "ACCOUNT_UPDATE",
+                "event_id": f"storm-au-{i:06d}",
+                "wallet_balance": -1.0,
+                "available_margin": -1.0,
+                "used_margin": 0.0,
+                "maint_margin": 0.0,
+            }
+        elif kind == "FILL_SETTLED":
+            ev = {
+                "kind": "FILL_SETTLED",
+                "event_id": f"storm-fs-{i:06d}",
+                "realized_pnl": 0.0,
+                "fee": round(rng.uniform(0.001, 0.05), 6),
+                "is_maker": rng.random() < 0.5,
+            }
+        elif kind == "PREDICTED_FILL":
+            ev = {
+                "kind": "PREDICTED_FILL",
+                "fill_price": round(rng.uniform(0.1, 100.0), 4),
+                "fill_qty": round(rng.uniform(1.0, 1000.0), 3),
+                "realized_pnl": 0.0,
+                "is_maker": rng.random() < 0.5,
+            }
+        elif kind == "FUNDING_FEE":
+            ev = {
+                "kind": "FUNDING_FEE",
+                "event_id": f"storm-ff-{i:06d}",
+                "funding_amount": round(rng.uniform(-1.0, 1.0), 6),
+            }
+        else:  # MARK_PRICE — FSM path via on_venue_event
+            ev = {
+                "kind": "MARK_PRICE",
+                "price": round(rng.uniform(0.1, 100.0), 4),
+            }
+        events.append(ev)
+    return events
+
+
+def sequence_hash(events: List[Dict[str, Any]]) -> str:
+    payload = json.dumps(events, sort_keys=True, separators=(",", ":")).encode()
+    return hashlib.sha256(payload).hexdigest()
+
+
+# ── Harness ──────────────────────────────────────────────────────────────────
+
+
+class ReactorHarness:
+    """Owns the kernel, the consumer queue, and the deadline scheduler."""
+
+    def __init__(self, *, kernel: Any = None) -> None:
+        if kernel is None:
+            # Real kernel, MOCK venue — the production bundle constructor.
+            from prod.clean_arch.dita_v2.launcher import build_launcher_bundle
+
+            bundle = build_launcher_bundle(venue_mode="MOCK", max_slots=1)
+            kernel = bundle.kernel
+        self.kernel = kernel
+        # Seed K = E so the synthetic storm starts reconciled.
+        if hasattr(self.kernel, "reset_and_seed"):
+            try:
+                self.kernel.reset_and_seed(25_000.0)
+            except Exception:
+                pass
+        self.reaction_hist = LatencyHistogram("venue_event_reaction")
+        self.kernel_hist = LatencyHistogram("kernel_call")
+        self.jitter_hist = LatencyHistogram("deadline_jitter")
+        self.account_clock = PlaneClock("account", ACCOUNT_STALENESS_NS)
+        self.early_fires = 0
+        self._last_k_capital = 25_000.0
+
+    def _fold(self, ev: Dict[str, Any]) -> None:
+        """Fold one storm event into the kernel, bracketing the FFI call."""
+        kind = ev.get("kind")
+        t0 = mono_ns()
+        if kind == "MARK_PRICE":
+            # FSM path: cheap venue event on slot 0 (flat slot → no-op walk).
+            from datetime import datetime, timezone
+
+            from prod.clean_arch.dita_v2.contracts import (
+                KernelEventKind,
+                TradeSide,
+                VenueEvent,
+                VenueEventStatus,
+            )
+
+            event = VenueEvent(
+                timestamp=datetime.now(timezone.utc),
+                event_id="",
+                trade_id="",
+                slot_id=0,
+                kind=KernelEventKind.MARK_PRICE,
+                status=VenueEventStatus.ACKED,
+                venue_order_id="",
+                venue_client_id="",
+                side=TradeSide.FLAT,
+                asset="STORMUSDT",
+                price=float(ev["price"]),
+                size=0.0,
+                filled_size=0.0,
+                remaining_size=0.0,
+                reason="",
+                raw_payload={},
+                metadata={},
+            )
+            self.kernel.on_venue_event(event)
+        else:
+            if kind == "ACCOUNT_UPDATE" and float(ev.get("wallet_balance", 0.0)) <= 0.0:
+                # Substitute the kernel's own k_capital (sentinel resolution;
+                # captured for free from prior fold returns — no extra FFI).
+                ev = dict(ev)
+                ev["wallet_balance"] = self._last_k_capital
+                ev["available_margin"] = self._last_k_capital
+            result = self.kernel.on_account_event(ev)
+            if isinstance(result, dict):
+                k_cap = result.get("k_capital")
+                if isinstance(k_cap, (int, float)) and k_cap > 0:
+                    self._last_k_capital = float(k_cap)
+        self.kernel_hist.record(mono_ns() - t0)
+        self.account_clock.tick()
+
+    async def run_storm(self, spec: StormSpec) -> HarnessReport:
+        events = generate_events(spec)
+        seq_hash = sequence_hash(events)
+
+        queue: asyncio.Queue = asyncio.Queue()
+        done = asyncio.Event()
+
+        # Deadline scheduler runs concurrently throughout the storm.
+        sched = DeadlineScheduler(jitter_hist=self.jitter_hist)
+        sched.start()
+        rng = random.Random(spec.seed ^ 0xD15EA5E)
+        fired_early_box = [0]
+        lo, hi = spec.deadline_spread_ms
+
+        def _mk_cb(due_holder: List[int]) -> Any:
+            def _cb() -> None:
+                if mono_ns() < due_holder[0]:
+                    fired_early_box[0] += 1
+            return _cb
+
+        for _ in range(spec.deadlines):
+            delay_ms = rng.uniform(lo, hi)
+            due = mono_ns() + int(delay_ms * 1e6)
+            sched.schedule_at(due, _mk_cb([due]))
+
+        async def producer() -> None:
+            i = 0
+            n = len(events)
+            while i < n:
+                if spec.arrival == "burst":
+                    burst_end = min(i + spec.burst_size, n)
+                    while i < burst_end:
+                        await queue.put((mono_ns(), i, events[i]))
+                        i += 1
+                    await asyncio.sleep(spec.inter_burst_ms / 1000.0)
+                elif spec.arrival == "poisson":
+                    await queue.put((mono_ns(), i, events[i]))
+                    i += 1
+                    await asyncio.sleep(rng.expovariate(1000.0))  # ~1k ev/s
+                else:  # uniform
+                    await queue.put((mono_ns(), i, events[i]))
+                    i += 1
+                    await asyncio.sleep(0.0005)
+            await queue.put((0, -1, None))  # sentinel
+
+        async def reactor() -> None:
+            while True:
+                inject_ns, idx, ev = await queue.get()
+                if ev is None:
+                    done.set()
+                    return
+                self._fold(ev)
+                if idx >= spec.warmup_events:
+                    self.reaction_hist.record(mono_ns() - inject_ns)
+
+        storm_t0 = mono_ns()
+        prod_task = asyncio.create_task(producer(), name="storm_producer")
+        react_task = asyncio.create_task(reactor(), name="storm_reactor")
+        await done.wait()
+        await prod_task
+        await react_task
+        storm_seconds = max(1e-9, (mono_ns() - storm_t0) / 1e9)
+        sustained_eps = len(events) / storm_seconds
+        # Let remaining short deadlines drain, then stop the driver.
+        await asyncio.sleep(min(2.5, hi / 1000.0 + 0.1))
+        await sched.stop()
+        self.early_fires = fired_early_box[0]
+
+        reaction_p99_ms = self.reaction_hist.percentile_ns(0.99) / 1e6
+        jitter_p99_ms = self.jitter_hist.percentile_ns(0.99) / 1e6
+        gate = {
+            "reaction_p99_ms": reaction_p99_ms,
+            "reaction_budget_ms": GATE_REACTION_P99_MS,
+            "jitter_p99_ms": jitter_p99_ms,
+            "jitter_budget_ms": GATE_JITTER_P99_MS,
+            "early_fires": self.early_fires,
+            "deadlines_fired": sched.fired_count,
+            "offered_events_per_s": round(
+                spec.burst_size / max(1e-9, spec.inter_burst_ms / 1000.0)
+                if spec.arrival == "burst" else 0.0, 1),
+            "sustained_events_per_s": round(sustained_eps, 1),
+            "storm_seconds": round(storm_seconds, 3),
+        }
+        passed = (
+            reaction_p99_ms < GATE_REACTION_P99_MS
+            and jitter_p99_ms < GATE_JITTER_P99_MS
+            and self.early_fires == 0
+        )
+        meta = {
+            "utc": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
+            "python": sys.version.split()[0],
+            "platform": platform.platform(),
+            "node": platform.node(),
+        }
+        return HarnessReport(
+            spec=spec,
+            histograms={
+                h.name: h.to_dict()
+                for h in (self.reaction_hist, self.kernel_hist, self.jitter_hist)
+            },
+            gate=gate,
+            passed=passed,
+            sequence_hash=seq_hash,
+            meta=meta,
+        )
+
+
+# ── CLI ──────────────────────────────────────────────────────────────────────
+
+
+async def _amain(args: argparse.Namespace) -> int:
+    spec = StormSpec(
+        n_events=args.events,
+        seed=args.seed,
+        deadlines=args.deadlines,
+        arrival=args.arrival,
+    )
+    harness = ReactorHarness()
+    report = await harness.run_storm(spec)
+    print(report.table())
+    if args.out:
+        out = Path(args.out)
+        out.parent.mkdir(parents=True, exist_ok=True)
+        out.write_text(report.to_json())
+        print(f"report written: {out}")
+    if args.gate and not report.passed:
+        return 1
+    return 0
+
+
+def main(argv: Optional[List[str]] = None) -> int:
+    ap = argparse.ArgumentParser(description="VIOLET V0 reactor latency harness")
+    ap.add_argument("--events", type=int, default=50_000)
+    ap.add_argument("--seed", type=int, default=42)
+    ap.add_argument("--deadlines", type=int, default=5_000)
+    ap.add_argument("--arrival", choices=("uniform", "poisson", "burst"), default="burst")
+    ap.add_argument("--out", type=str, default="")
+    ap.add_argument("--gate", action="store_true")
+    args = ap.parse_args(argv)
+    return asyncio.run(_amain(args))
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/prod/clean_arch/violet/test_violet_clock.py b/prod/clean_arch/violet/test_violet_clock.py
new file mode 100644
index 0000000..0b034b1
--- /dev/null
+++ b/prod/clean_arch/violet/test_violet_clock.py
@@ -0,0 +1,80 @@
+"""V0: PlaneClock + LatencyHistogram unit tests."""
+
+from __future__ import annotations
+
+import sys
+
+sys.path.insert(0, "/mnt/dolphinng5_predict")
+
+import pytest
+
+from prod.clean_arch.violet.clock import LatencyHistogram, PlaneClock
+
+
+def test_planeclock_seq_monotonic_and_stamp():
+    c = PlaneClock("scan", staleness_budget_ns=10)
+    assert c.seq == 0 and c.last_mono_ns == -1
+    assert c.tick(now_ns=100) == 1
+    assert c.tick(now_ns=200) == 2
+    assert c.seq == 2 and c.last_mono_ns == 200
+
+
+def test_planeclock_age_math_with_injected_now():
+    c = PlaneClock("venue", staleness_budget_ns=1_000)
+    c.tick(now_ns=5_000)
+    assert c.age_ns(now_ns=5_400) == 400
+    # clock never goes backwards in age
+    assert c.age_ns(now_ns=4_000) == 0
+
+
+def test_planeclock_staleness_boundary_is_strict():
+    """age == budget → NOT stale; age > budget → stale (MHS FIX-9 lesson:
+    a threshold equal to the natural refresh period must not flap)."""
+    c = PlaneClock("ob", staleness_budget_ns=1_000)
+    c.tick(now_ns=0)
+    assert c.is_stale(now_ns=1_000) is False     # exactly at budget
+    assert c.is_stale(now_ns=1_001) is True      # one ns past
+
+
+def test_planeclock_never_ticked_is_not_stale():
+    c = PlaneClock("account", staleness_budget_ns=1)
+    assert c.age_ns(now_ns=10**12) == -1
+    assert c.is_stale(now_ns=10**12) is False    # "not yet alive" ≠ "stale"
+
+
+def test_planeclock_snapshot_shape():
+    c = PlaneClock("scan", staleness_budget_ns=500)
+    c.tick(now_ns=1)
+    s = c.snapshot()
+    for key in ("name", "seq", "last_mono_ns", "age_ns", "stale", "budget_ns"):
+        assert key in s
+
+
+def test_histogram_exact_percentiles():
+    h = LatencyHistogram("t")
+    for v in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]:
+        h.record(v)
+    assert h.percentile_ns(0.50) == 5
+    assert h.percentile_ns(0.90) == 9
+    assert h.percentile_ns(0.99) == 10
+    assert h.count == 10
+
+
+def test_histogram_reservoir_overflow_counts_but_drops():
+    h = LatencyHistogram("t", reservoir=5)
+    for v in range(10):
+        h.record(v)
+    assert h.count == 10
+    d = h.to_dict()
+    assert d["retained"] == 5 and d["overflow_dropped"] == 5
+
+
+def test_histogram_report_contains_percentiles():
+    h = LatencyHistogram("xyz")
+    h.record(1_000_000)  # 1 ms
+    r = h.report()
+    assert "xyz" in r and "p99" in r
+
+
+if __name__ == "__main__":
+    raise SystemExit(pytest.main([__file__, "-v"]))
diff --git a/prod/clean_arch/violet/test_violet_deadline_scheduler.py b/prod/clean_arch/violet/test_violet_deadline_scheduler.py
new file mode 100644
index 0000000..53bf826
--- /dev/null
+++ b/prod/clean_arch/violet/test_violet_deadline_scheduler.py
@@ -0,0 +1,112 @@
+"""V0: DeadlineScheduler — ordering, cancellation, early-wake, jitter."""
+
+from __future__ import annotations
+
+import asyncio
+import random
+import sys
+
+sys.path.insert(0, "/mnt/dolphinng5_predict")
+
+import pytest
+
+from prod.clean_arch.violet.clock import DeadlineScheduler, LatencyHistogram, mono_ns
+
+
+@pytest.mark.asyncio
+async def test_deadlines_fire_in_due_order_after_shuffled_insert():
+    fired: list[int] = []
+    sched = DeadlineScheduler()
+    sched.start()
+    base = mono_ns()
+    order = list(range(1_000))
+    random.Random(7).shuffle(order)
+    for k in order:
+        due = base + (k + 1) * 1_000_000  # 1ms apart, shuffled insertion
+        sched.schedule_at(due, (lambda kk=k: fired.append(kk)))
+    await asyncio.sleep(1.3)
+    await sched.stop()
+    assert len(fired) == 1_000
+    assert fired == sorted(fired)
+
+
+@pytest.mark.asyncio
+async def test_cancellation_prevents_fire():
+    fired: list[str] = []
+    sched = DeadlineScheduler()
+    sched.start()
+    keep = sched.schedule_in(30, lambda: fired.append("keep"))
+    kill = sched.schedule_in(30, lambda: fired.append("kill"))
+    kill.cancel()
+    await asyncio.sleep(0.12)
+    await sched.stop()
+    assert fired == ["keep"]
+    assert kill.cancelled and not kill.fired
+    assert keep.fired
+
+
+@pytest.mark.asyncio
+async def test_early_wake_on_earlier_insert():
+    """A deadline inserted BELOW the current head must fire on time even when
+    the driver was sleeping toward a much later head — the early-wake path."""
+    sched = DeadlineScheduler(max_sleep_ms=5_000)  # tick alone would be too slow
+    jit = LatencyHistogram("j")
+    sched.jitter_hist = jit
+    sched.start()
+    fired_at: list[int] = []
+    sched.schedule_in(4_000, lambda: None)              # far head; driver sleeps
+    await asyncio.sleep(0.05)                            # driver now parked
+    due = mono_ns() + 20_000_000                         # 20ms from now
+    sched.schedule_at(due, lambda: fired_at.append(mono_ns()))
+    await asyncio.sleep(0.15)
+    await sched.stop()
+    assert fired_at, "early deadline never fired — early-wake broken"
+    lateness_ms = (fired_at[0] - due) / 1e6
+    assert lateness_ms < 25.0, f"early-wake too late: {lateness_ms:.1f}ms"
+
+
+@pytest.mark.asyncio
+async def test_no_early_fires_and_jitter_budget_under_cpu_noise():
+    jit = LatencyHistogram("jitter")
+    sched = DeadlineScheduler(jitter_hist=jit)
+    sched.start()
+    early = [0]
+    rng = random.Random(11)
+    dues = []
+    for _ in range(400):
+        due = mono_ns() + int(rng.uniform(10, 800) * 1e6)
+        dues.append(due)
+        sched.schedule_at(due, (lambda d=due: early.__setitem__(0, early[0] + 1) if mono_ns() < d else None))
+
+    async def cpu_noise():
+        end = mono_ns() + int(0.9e9)
+        while mono_ns() < end:
+            sum(i * i for i in range(2_000))
+            await asyncio.sleep(0)
+
+    noise = asyncio.create_task(cpu_noise())
+    await asyncio.sleep(1.0)
+    noise.cancel()
+    await sched.stop()
+    assert early[0] == 0, "deadline fired EARLY"
+    assert sched.fired_count == 400
+    p99_ms = jit.percentile_ns(0.99) / 1e6
+    assert p99_ms < 25.0, f"jitter p99 {p99_ms:.2f}ms exceeds 25ms budget"
+
+
+@pytest.mark.asyncio
+async def test_callback_exception_does_not_kill_driver():
+    errors: list[str] = []
+    sched = DeadlineScheduler(on_error=lambda dl, e: errors.append(str(e)))
+    sched.start()
+    fired: list[str] = []
+    sched.schedule_in(10, lambda: (_ for _ in ()).throw(RuntimeError("boom")))
+    sched.schedule_in(40, lambda: fired.append("after"))
+    await asyncio.sleep(0.12)
+    await sched.stop()
+    assert errors and "boom" in errors[0]
+    assert fired == ["after"], "driver died after callback exception"
+
+
+if __name__ == "__main__":
+    raise SystemExit(pytest.main([__file__, "-v"]))
diff --git a/prod/clean_arch/violet/test_violet_harness.py b/prod/clean_arch/violet/test_violet_harness.py
new file mode 100644
index 0000000..1018206
--- /dev/null
+++ b/prod/clean_arch/violet/test_violet_harness.py
@@ -0,0 +1,68 @@
+"""V0: ReactorHarness — determinism, report shape, MOCK bundle wiring."""
+
+from __future__ import annotations
+
+import asyncio
+import json
+import sys
+
+sys.path.insert(0, "/mnt/dolphinng5_predict")
+sys.path.insert(0, "/mnt/dolphinng5_predict/nautilus_dolphin")
+
+import pytest
+
+from prod.clean_arch.violet.harness import (
+    HarnessReport,
+    ReactorHarness,
+    StormSpec,
+    generate_events,
+    sequence_hash,
+)
+
+
+def test_seed_determinism_sequence_hash():
+    a = generate_events(StormSpec(n_events=500, seed=42))
+    b = generate_events(StormSpec(n_events=500, seed=42))
+    c = generate_events(StormSpec(n_events=500, seed=43))
+    assert sequence_hash(a) == sequence_hash(b)
+    assert sequence_hash(a) != sequence_hash(c)
+
+
+def test_event_mix_kinds_only_known():
+    spec = StormSpec(n_events=300, seed=1)
+    kinds = {e["kind"] for e in generate_events(spec)}
+    assert kinds <= set(spec.mix.keys())
+
+
+@pytest.mark.asyncio
+async def test_small_storm_report_shape_real_kernel():
+    """Drives the REAL Rust kernel through a tiny storm via the MOCK bundle."""
+    spec = StormSpec(n_events=400, seed=7, deadlines=50,
+                     deadline_spread_ms=(5, 200), warmup_events=50)
+    harness = ReactorHarness()
+    report = await harness.run_storm(spec)
+    assert isinstance(report, HarnessReport)
+    payload = json.loads(report.to_json())
+    for key in ("spec", "histograms", "gate", "passed", "sequence_hash", "meta"):
+        assert key in payload
+    for hist in ("venue_event_reaction", "kernel_call", "deadline_jitter"):
+        assert hist in payload["histograms"]
+        assert payload["histograms"][hist]["count"] > 0
+    assert payload["gate"]["early_fires"] == 0
+    assert payload["gate"]["deadlines_fired"] == 50
+    # reaction samples exclude warmup
+    assert payload["histograms"]["venue_event_reaction"]["count"] == 400 - 50
+
+
+@pytest.mark.asyncio
+async def test_storm_does_not_freeze_kernel_capital():
+    """Account-event storm must leave the kernel tradeable (no reconcile
+    freeze from synthetic wallet noise — wallet values are kept coherent)."""
+    spec = StormSpec(n_events=300, seed=3, deadlines=10, warmup_events=10)
+    harness = ReactorHarness()
+    await harness.run_storm(spec)
+    assert harness.kernel.is_capital_frozen() is False
+
+
+if __name__ == "__main__":
+    raise SystemExit(pytest.main([__file__, "-v"]))
diff --git a/prod/clean_arch/violet/test_violet_v0_latency_gate.py b/prod/clean_arch/violet/test_violet_v0_latency_gate.py
new file mode 100644
index 0000000..e35fab2
--- /dev/null
+++ b/prod/clean_arch/violet/test_violet_v0_latency_gate.py
@@ -0,0 +1,63 @@
+"""V0 LATENCY GATE — run on the prod host; this test IS the V0 stage gate.
+
+Excluded from default runs via the ``gate`` marker:
+    pytest -m gate prod/clean_arch/violet/test_violet_v0_latency_gate.py
+
+Budgets (charter): venue_event_reaction p99 < 10 ms; deadline_jitter
+p99 < 25 ms; zero early fires. The JSON report is the gate artifact —
+archived to prod/VIOLET_dev/reports/.
+"""
+
+from __future__ import annotations
+
+import sys
+import time
+from pathlib import Path
+
+sys.path.insert(0, "/mnt/dolphinng5_predict")
+sys.path.insert(0, "/mnt/dolphinng5_predict/nautilus_dolphin")
+
+import pytest
+
+from prod.clean_arch.violet.harness import (
+    GATE_JITTER_P99_MS,
+    GATE_REACTION_P99_MS,
+    ReactorHarness,
+    StormSpec,
+)
+
+REPORT_DIR = Path("/mnt/dolphinng5_predict/prod/VIOLET_dev/reports")
+
+
+@pytest.mark.gate
+@pytest.mark.asyncio
+async def test_v0_latency_gate_storm():
+    spec = StormSpec(n_events=50_000, seed=42, deadlines=5_000,
+                     arrival="burst", warmup_events=1_000)
+    harness = ReactorHarness()
+    report = await harness.run_storm(spec)
+
+    REPORT_DIR.mkdir(parents=True, exist_ok=True)
+    stamp = time.strftime("%Y%m%d_%H%M%S", time.gmtime())
+    out = REPORT_DIR / f"violet_v0_latency_{stamp}.json"
+    out.write_text(report.to_json())
+    print()
+    print(report.table())
+    print(f"report: {out}")
+
+    g = report.gate
+    assert g["early_fires"] == 0, "deadline fired EARLY"
+    assert g["deadlines_fired"] == spec.deadlines
+    assert g["reaction_p99_ms"] < GATE_REACTION_P99_MS, (
+        f"venue_event_reaction p99 {g['reaction_p99_ms']:.3f}ms "
+        f">= {GATE_REACTION_P99_MS}ms budget"
+    )
+    assert g["jitter_p99_ms"] < GATE_JITTER_P99_MS, (
+        f"deadline_jitter p99 {g['jitter_p99_ms']:.3f}ms "
+        f">= {GATE_JITTER_P99_MS}ms budget"
+    )
+    assert report.passed is True
+
+
+if __name__ == "__main__":
+    raise SystemExit(pytest.main([__file__, "-v", "-m", "gate"]))