diff --git a/prod/exec_unified/__init__.py b/prod/exec_unified/__init__.py
index 2fd7ad0..3c2bc02 100644
--- a/prod/exec_unified/__init__.py
+++ b/prod/exec_unified/__init__.py
@@ -13,19 +13,25 @@ from .contract import (
     ExecutionAdvice,
     ExecutionRequest,
     ProtectiveSpec,
+    SGrade,
     Side,
     UrgencyClass,
 )
+from .executor import ExecuteResult, ExecuteStatus, UnifiedExecutor
 from .router import ExecutionMethod, RoutingDecision, TtlDiscipline, decide
 
 __all__ = [
+    "ExecuteResult",
+    "ExecuteStatus",
     "ExecutionAdvice",
     "ExecutionMethod",
     "ExecutionRequest",
     "ProtectiveSpec",
     "RoutingDecision",
+    "SGrade",
     "Side",
     "TtlDiscipline",
+    "UnifiedExecutor",
     "UrgencyClass",
     "decide",
 ]
diff --git a/prod/exec_unified/_constants.py b/prod/exec_unified/_constants.py
index 2e5b5fb..95270bc 100644
--- a/prod/exec_unified/_constants.py
+++ b/prod/exec_unified/_constants.py
@@ -29,6 +29,12 @@ ACQUIRE_MAX_CHASES: int = 0
 # question: 2× vs ATR-scaled). PROVISIONAL default.
 PROTECTIVE_STOP_MULT_DEFAULT: Decimal = Decimal("2.0")
 
+# Maker-quote lifetime for UNBOUNDED-TTL urgencies (HARVEST/ACQUIRE): how long a resting
+# quote lives before the drive loop sweeps + re-evaluates it. Bounded quote lifetime +
+# cancel/replace is the certified GTX discipline (spec §4-16). PROVISIONAL — calibrate vs
+# L8 GTX fill latencies; measured in injected-clock seconds, never a hardcoded loop literal.
+MAKER_QUOTE_TTL_S: float = 6.0
+
 # Requote hot-window: after an OWN fill, refuse to re-quote for this long because the
 # REST venue reconcile lags the WS fill by seconds — re-quoting inside it double-enters.
 # Provenance: live double-entry, pink_direct.py:1055 / :1323 (2026-06-10). Measured in
diff --git a/prod/exec_unified/contract.py b/prod/exec_unified/contract.py
index 4158e13..c99308d 100644
--- a/prod/exec_unified/contract.py
+++ b/prod/exec_unified/contract.py
@@ -47,6 +47,24 @@ class UrgencyClass(Enum):
                          UrgencyClass.HARVEST, UrgencyClass.ROTATE)
 
 
+class SGrade(Enum):
+    """Size axis — orthogonal to the T-tier smartness ladder (spec §15.2).
+
+    Computed at intake from Appendix E's power-law depth model (per-asset, stress-adjusted),
+    or supplied by the caller. Below T14 the layer executes S0/S1 directly and REFUSES S2+
+    whole (the pain-fence) so nobody meets the large-size pain class by accident.
+    """
+
+    S0 = 0  # size << top-of-book depth (walk < 1 tick) — any tier executes directly
+    S1 = 1  # walks visible levels (expected walk >= spread) — T2+ prices the walk
+    S2 = 2  # exceeds book capacity in the urgency window — must be SLICED; refused below T14
+    S3 = 3  # size IS the market (footprint moves MM behaviour) — MALKHUT/VIBRASS territory
+
+    @property
+    def needs_slicing(self) -> bool:
+        return self in (SGrade.S2, SGrade.S3)
+
+
 @dataclass(frozen=True)
 class ProtectiveSpec:
     """Attach-a-dead-man's-stop geometry (spec §10). Mark-based, rides the entry order.
@@ -113,6 +131,8 @@ class ExecutionRequest:
     protective: ProtectiveSpec | None = None
     advice: ExecutionAdvice | None = None
     deadline_ms: int | None = None           # caller's patience budget (ROTATE/ACQUIRE)
+    s_grade: SGrade = SGrade.S0              # size regime (§15.2); default S0 = fits at touch
+    parent_request_id: str | None = None    # slicer family linkage (§15.2 T*.s), telemetry only
 
     def __post_init__(self) -> None:
         if not self.request_id:
diff --git a/prod/exec_unified/drive_loop.py b/prod/exec_unified/drive_loop.py
index d049f04..46bdb44 100644
--- a/prod/exec_unified/drive_loop.py
+++ b/prod/exec_unified/drive_loop.py
@@ -36,6 +36,9 @@ OPENISH = frozenset({
 })
 # Stages that mean the position is gone. pink_direct.py:1106.
 CLOSED_STAGES = frozenset({"POSITION_CLOSED", "CLOSED", "TRADE_TERMINAL_WRITTEN", "IDLE"})
+# Stages that mean the venue rejected our order (post-only would cross, etc.).
+# pink_direct.py:1000. A rejected maker quote still registers → resolves via the TTL path.
+REJECTED_STAGES = frozenset({"ORDER_REJECTED", "EXIT_REJECTED"})
 
 
 @dataclass(frozen=True)
@@ -64,6 +67,12 @@ class ResubmitPlan:
     reduce_only: bool
 
 
+# The plan the venue receives is the same shape whether it is an initial submit (executor,
+# attempt 0) or a rebuilt retry/escalation (drive loop). "Resubmit" is the origin name;
+# OrderPlan is the role name the executor uses.
+OrderPlan = ResubmitPlan
+
+
 class ExecPort(Protocol):
     """The single seam to kernel + venue. Fakeable; the loop touches the world ONLY here."""
 
@@ -103,11 +112,21 @@ class DriveLoop:
 
     # ── classification ───────────────────────────────────────────────────────
     def _is_resolved(self, wo: WorkingOrder, slot: SlotView) -> bool:
-        """Entry filled or exit done, per kernel truth (pink _entry_filled/_exit_done)."""
+        """Entry filled or exit done, per kernel truth (pink _entry_filled/_exit_done, L1099).
+
+        ENTER: our entry filled — the slot carries OUR clientOrderId (the kernel tags the new
+        position with it; clientOrderId echo is the best-practice fill key, audit H5) and shows
+        size + an open stage.
+
+        EXIT: the position is gone — size drained or a closed stage. **Deliberately SIZE-based,
+        not trade_id-based**: pink_direct.py:1105 could compare `slot_tid != wo.trade_id` only
+        because it REUSED the position's trade_id for the exit intent. This layer is agnostic
+        (contract §2) — the caller mints a fresh request_id for the exit and never hands us the
+        position's id — so an exit is "done" iff the position closed, which is the size signal.
+        """
         if wo.action is Action.ENTER:
             return slot.trade_id == wo.request_id and slot.size > 0 and slot.stage in OPENISH
-        return (slot.trade_id != wo.request_id or slot.size <= 0
-                or slot.stage in CLOSED_STAGES)
+        return slot.size <= 0 or slot.stage in CLOSED_STAGES
 
     def after_submit(self, wo: WorkingOrder, *, rejected: bool) -> str:
         """Classify a maker submit: filled-now / working / rejected. pink L975.
diff --git a/prod/exec_unified/executor.py b/prod/exec_unified/executor.py
new file mode 100644
index 0000000..0f138ea
--- /dev/null
+++ b/prod/exec_unified/executor.py
@@ -0,0 +1,146 @@
+"""UnifiedExecutor — the initial-submit pipeline (spec §2, §6, §15.2).
+
+The two halves of the engine:
+  * ``UnifiedExecutor.execute(request, snapshot)`` — a NEW ExecutionRequest enters, is
+    graded/refused, routed (whether-maker), placed (where-in-book), and submitted. This file.
+  * ``DriveLoop`` — the working-order lifecycle after submit (TTL sweep, requote, escalate).
+
+This is the analogue of ``pink_direct.py``'s in-``step`` execution block (L1645-1700):
+router-decides-HOW → placer-sets-WHERE → submit → register working. Pure orchestration over
+the injected ``ExecPort``; it never sees capital/leverage/asset (contract §2).
+
+Composition rulings encoded here (not re-derivable, so read them):
+  * Placer declines (spread gate fails) → **cross only if the urgency crosses on expiry**
+    (PROTECT/HARVEST/ROTATE). ACQUIRE **abandons** — a missed entry is free (§4-1).
+  * The S2+ pain-fence (§15.2): below T14 an S2/S3 request is REFUSED WHOLE, loudly — never
+    silently sliced or dumped. Nobody meets the large-size pain class by accident.
+"""
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from decimal import Decimal
+from enum import Enum
+
+from . import _constants as K
+from .contract import ExecutionRequest, SGrade, Side, UrgencyClass
+from .drive_loop import (
+    REJECTED_STAGES,
+    Action,
+    DriveLoop,
+    ExecutionMethod,
+    OrderPlan,
+    build_working_order,
+)
+from .placer import MarketSnapshot, pre_submit
+from .router import RoutingDecision, TtlDiscipline, decide
+from .working import WorkingOrder
+
+LOGGER = logging.getLogger(__name__)
+
+
+class ExecuteStatus(Enum):
+    REFUSED_S2 = "refused_s2"          # pain-fence: S2+ below T14, refused whole
+    CROSSED_TAKER = "crossed_taker"    # crossed the spread now (CATASTROPHIC, or maker-impossible cross)
+    RESTING_MAKER = "resting_maker"    # post-only quote resting; drive loop owns it now
+    REJECTED_RESTING = "rejected_resting"  # post-only rejected; registered for instant TTL resolve
+    FILLED_ON_SUBMIT = "filled_on_submit"  # order filled during the submit round-trip
+    ABANDONED = "abandoned"            # ACQUIRE, maker impossible, no cross — a free miss
+
+
+@dataclass(frozen=True)
+class ExecuteResult:
+    status: ExecuteStatus
+    decision: RoutingDecision | None
+    plan: OrderPlan | None
+    working: WorkingOrder | None
+    reason: str
+
+
+def _ttl_seconds(request: ExecutionRequest, decision: RoutingDecision) -> float:
+    """Working-quote lifetime before the drive loop re-evaluates it, from the urgency's TTL
+    discipline (spec §6). BOUNDED→its ms; DEADLINE→caller's deadline_ms; UNBOUNDED→the
+    certified GTX quote lifetime (§4-16)."""
+    if decision.ttl is TtlDiscipline.BOUNDED_MS and decision.max_ms is not None:
+        return decision.max_ms / 1000.0
+    if decision.ttl is TtlDiscipline.DEADLINE:
+        return (request.deadline_ms or int(K.MAKER_QUOTE_TTL_S * 1000)) / 1000.0
+    return K.MAKER_QUOTE_TTL_S  # UNBOUNDED (HARVEST/ACQUIRE): bounded by chases, not clock
+
+
+class UnifiedExecutor:
+    """One per exec instance. Shares its ``DriveLoop``'s port + registry."""
+
+    def __init__(self, drive_loop: DriveLoop, logger: logging.Logger = LOGGER) -> None:
+        self.dl = drive_loop
+        self.port = drive_loop.port
+        self.registry = drive_loop.registry
+        self.log = logger
+
+    async def execute(self, request: ExecutionRequest,
+                      snapshot: MarketSnapshot) -> ExecuteResult:
+        # ── 1. S2+ pain-fence (§15.2): refuse large size WHOLE, loudly, below T14 ──
+        if request.s_grade.needs_slicing:
+            reason = (f"S-grade {request.s_grade.name} exceeds book capacity — REFUSED whole "
+                      f"below T14. Route through a slicer (TWAP/VWAP) or take a tier decision. "
+                      f"Silently dumping this size is the pain class the fence exists to prevent.")
+            self.log.error("executor: %s (%s size=%s)", reason, request.asset, request.size)
+            return ExecuteResult(ExecuteStatus.REFUSED_S2, None, None, None, reason)
+
+        decision = decide(request)
+        action = Action.ENTER if request.urgency is UrgencyClass.ACQUIRE else Action.EXIT
+        base = request.request_id
+        rid0 = request.client_order_id_core(0)          # unique per attempt (audit H4)
+        reduce_only = action is Action.EXIT
+
+        # ── 2. TAKER: cross now (CATASTROPHIC). No cleverness, ever. ──
+        if decision.method is ExecutionMethod.TAKER:
+            return await self._cross(request, decision, action, rid0, base,
+                                     reduce_only, reason=decision.rationale)
+
+        # ── 3. MAKER: ask the placer WHERE (spread gate + touch, quantized). ──
+        placement = pre_submit(request, decision, snapshot)
+        if placement is None:
+            # Maker impossible right now (spread too wide). Compose by urgency:
+            if decision.cross_on_expiry:
+                return await self._cross(request, decision, action, rid0, base,
+                                         reduce_only, reason="spread_gate: maker impossible → cross")
+            # ACQUIRE: a missed entry is free — abandon, never cross (§4-1).
+            self.log.info("executor: %s ACQUIRE maker impossible (spread) → abandon", base)
+            return ExecuteResult(ExecuteStatus.ABANDONED, decision, None, None,
+                                 "spread_gate: ACQUIRE abandons, never crosses")
+
+        # ── 4. Submit the maker quote, then classify (filled / resting / rejected). ──
+        maker_plan = OrderPlan(
+            request_id=rid0, base_request_id=base, asset=request.asset, side=request.side,
+            action=action, method=ExecutionMethod.MAKER, limit_price=placement.limit_price,
+            attempt=0, reduce_only=reduce_only,
+        )
+        await self.port.submit(maker_plan)
+        wo = build_working_order(
+            request_id=rid0, base_request_id=base, asset=request.asset, side=request.side,
+            action=action, limit_price=placement.limit_price, decision=decision,
+            clock=self.port.clock(), ttl_s=_ttl_seconds(request, decision), attempt=0,
+        )
+        rejected = self.port.slot_view().stage in REJECTED_STAGES
+        cls = self.dl.after_submit(wo, rejected=rejected)
+        if cls == "immediate_fill":
+            return ExecuteResult(ExecuteStatus.FILLED_ON_SUBMIT, decision, maker_plan, None,
+                                 "maker filled on submit")
+        if cls == "working_reject":
+            return ExecuteResult(ExecuteStatus.REJECTED_RESTING, decision, maker_plan, wo,
+                                 "post-only rejected — instant TTL resolve")
+        return ExecuteResult(ExecuteStatus.RESTING_MAKER, decision, maker_plan, wo,
+                             "maker quote resting; drive loop owns it")
+
+    async def _cross(self, request: ExecutionRequest, decision: RoutingDecision,
+                     action: Action, rid0: str, base: str, reduce_only: bool,
+                     *, reason: str) -> ExecuteResult:
+        plan = OrderPlan(
+            request_id=rid0, base_request_id=base, asset=request.asset, side=request.side,
+            action=action, method=ExecutionMethod.TAKER, limit_price=Decimal(0),
+            attempt=0, reduce_only=reduce_only,
+        )
+        await self.port.submit(plan)
+        await self.port.pump()  # a market cross settles fast; drain it before returning
+        return ExecuteResult(ExecuteStatus.CROSSED_TAKER, decision, plan, None, reason)
diff --git a/prod/exec_unified/test_executor.py b/prod/exec_unified/test_executor.py
new file mode 100644
index 0000000..32faa99
--- /dev/null
+++ b/prod/exec_unified/test_executor.py
@@ -0,0 +1,176 @@
+"""UnifiedExecutor composition tests — the initial-submit pipeline (spec §2/§6/§15.2).
+
+Each asserts a composition ruling that is NOT re-derivable from the parts:
+  * S2+ pain-fence refuses whole (mutation: let S2 through -> RED)
+  * placer-declines → cross iff urgency crosses; ACQUIRE abandons (mutation: cross ACQUIRE -> RED)
+  * TTL derived from the urgency's discipline
+
+Async via asyncio.run (no pytest-asyncio needed). Run:
+    /home/dolphin/siloqy_env/bin/python3 -m pytest prod/exec_unified/test_executor.py -q
+"""
+from __future__ import annotations
+
+import asyncio
+from decimal import Decimal
+
+from prod.exec_unified.contract import ExecutionRequest, SGrade, Side, UrgencyClass
+from prod.exec_unified.drive_loop import Action, DriveLoop, SlotView
+from prod.exec_unified.executor import ExecuteStatus, UnifiedExecutor
+from prod.exec_unified.placer import MarketSnapshot
+from prod.exec_unified.router import ExecutionMethod
+from prod.exec_unified.working import WorkingRegistry
+
+NARROW = MarketSnapshot(best_bid=Decimal("100"), best_ask=Decimal("100.05"),
+                        spread_bps=Decimal("5"), tick=Decimal("0.01"), step=Decimal("0.001"))
+WIDE = MarketSnapshot(best_bid=Decimal("100"), best_ask=Decimal("100.5"),
+                      spread_bps=Decimal("20"), tick=Decimal("0.01"), step=Decimal("0.001"))
+FLAT = SlotView(trade_id="", stage="ACKED", size=Decimal(0))
+# An exit is submitted against an OPEN position — the slot still shows it (size > 0) until
+# the maker close fills. A flat slot at exit-submit time is nonsensical.
+OPEN = SlotView(trade_id="pos-1", stage="POSITION_OPEN", size=Decimal("1"))
+
+
+class FakeClock:
+    def __init__(self, t=1000.0): self.t = t
+    def __call__(self): return self.t
+
+
+class FakePort:
+    def __init__(self, clock, slot=FLAT):
+        self._c = clock
+        self.slot = slot
+        self.submits = []
+        self.pumps = 0
+    def clock(self): return self._c()
+    def slot_view(self): return self.slot
+    def last_own_fill_at(self): return -1e9
+    async def pump(self): self.pumps += 1
+    async def cancel(self, wo): pass
+    async def open_positions(self): return []
+    async def submit(self, plan): self.submits.append(plan)
+
+
+def _exec(slot=FLAT):
+    clock = FakeClock()
+    port = FakePort(clock, slot)
+    reg = WorkingRegistry(clock)
+    return UnifiedExecutor(DriveLoop(port, reg)), port, reg
+
+
+def _req(urgency, side=Side.BUY, **kw):
+    base = dict(request_id="req", asset="BTCUSDT", side=side, size=Decimal("0.001"),
+                urgency=urgency)
+    base.update(kw)
+    return ExecutionRequest(**base)
+
+
+def _run(coro):
+    return asyncio.run(coro)
+
+
+# ── S2+ pain-fence ───────────────────────────────────────────────────────────
+
+def test_s2_refused_whole_no_submit():
+    # Mutation: drop the fence -> this order would submit and RED here.
+    ex, port, _ = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.ACQUIRE, s_grade=SGrade.S2), NARROW))
+    assert r.status is ExecuteStatus.REFUSED_S2
+    assert port.submits == []                      # nothing hit the venue
+    assert "REFUSED" in r.reason
+
+
+def test_s3_also_refused():
+    ex, port, _ = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.HARVEST, side=Side.SELL, s_grade=SGrade.S3), NARROW))
+    assert r.status is ExecuteStatus.REFUSED_S2
+    assert port.submits == []
+
+
+def test_s0_default_not_refused():
+    ex, port, _ = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.ACQUIRE), NARROW))   # default S0
+    assert r.status is not ExecuteStatus.REFUSED_S2
+
+
+# ── routing → submit ─────────────────────────────────────────────────────────
+
+def test_catastrophic_crosses_taker():
+    ex, port, _ = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.CATASTROPHIC, side=Side.SELL), NARROW))
+    assert r.status is ExecuteStatus.CROSSED_TAKER
+    assert len(port.submits) == 1
+    assert port.submits[0].method is ExecutionMethod.TAKER
+    assert port.submits[0].reduce_only is True         # exit reduces
+    assert port.submits[0].request_id == "req-0"       # per-attempt id (H4)
+
+
+def test_acquire_narrow_spread_rests_maker():
+    ex, port, reg = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.ACQUIRE), NARROW))
+    assert r.status is ExecuteStatus.RESTING_MAKER
+    assert port.submits[0].method is ExecutionMethod.MAKER
+    assert port.submits[0].limit_price == Decimal("100")   # placed at bid (touch), quantized
+    assert reg.working("req-0") is not None                 # drive loop now owns it
+
+
+def test_acquire_wide_spread_abandons_never_crosses():
+    # THE key composition ruling: a missed entry is free (§4-1). Mutation: cross here -> RED.
+    ex, port, _ = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.ACQUIRE), WIDE))
+    assert r.status is ExecuteStatus.ABANDONED
+    assert port.submits == []                          # NOT crossed
+
+
+def test_protect_wide_spread_crosses():
+    # Contrast with ACQUIRE: PROTECT crosses when maker is impossible (cross_on_expiry).
+    ex, port, _ = _exec()
+    r = _run(ex.execute(_req(UrgencyClass.PROTECT, side=Side.SELL), WIDE))
+    assert r.status is ExecuteStatus.CROSSED_TAKER
+    assert port.submits[0].method is ExecutionMethod.TAKER
+
+
+def test_harvest_narrow_rests_maker():
+    ex, port, reg = _exec(slot=OPEN)
+    r = _run(ex.execute(_req(UrgencyClass.HARVEST, side=Side.SELL), NARROW))
+    assert r.status is ExecuteStatus.RESTING_MAKER
+    assert port.submits[0].limit_price == Decimal("100.05")   # SELL at ask (touch)
+
+
+def test_maker_filled_on_submit():
+    ex, port, reg = _exec(slot=SlotView(trade_id="req-0", stage="POSITION_OPEN", size=Decimal("1")))
+    r = _run(ex.execute(_req(UrgencyClass.ACQUIRE), NARROW))
+    assert r.status is ExecuteStatus.FILLED_ON_SUBMIT
+    assert reg.working("req-0") is None                # filled → not left working
+
+
+def test_post_only_rejected_registers_for_instant_resolve():
+    ex, port, reg = _exec(slot=SlotView(trade_id="", stage="ORDER_REJECTED", size=Decimal(0)))
+    r = _run(ex.execute(_req(UrgencyClass.ACQUIRE), NARROW))
+    assert r.status is ExecuteStatus.REJECTED_RESTING
+    wo = reg.working("req-0")
+    assert wo is not None
+    assert reg.expired() == [wo]                        # deadline pulled to now
+
+
+# ── TTL derivation from urgency discipline ───────────────────────────────────
+
+def test_ttl_protect_bounded_2s():
+    ex, port, reg = _exec(slot=OPEN)
+    _run(ex.execute(_req(UrgencyClass.PROTECT, side=Side.SELL), NARROW))
+    wo = reg.working("req-0")
+    assert wo.deadline - wo.created == 2.0              # BOUNDED_MS = 2000 ms
+
+
+def test_ttl_rotate_from_deadline_ms():
+    ex, port, reg = _exec(slot=OPEN)
+    _run(ex.execute(_req(UrgencyClass.ROTATE, side=Side.SELL, deadline_ms=30000), NARROW))
+    wo = reg.working("req-0")
+    assert wo.deadline - wo.created == 30.0             # caller's deadline
+
+
+def test_ttl_acquire_unbounded_uses_quote_lifetime():
+    from prod.exec_unified import _constants as K
+    ex, port, reg = _exec()
+    _run(ex.execute(_req(UrgencyClass.ACQUIRE), NARROW))
+    wo = reg.working("req-0")
+    assert wo.deadline - wo.created == K.MAKER_QUOTE_TTL_S   # bounded by chases, not clock