diff --git a/decnet/ttp/store/impl/database.py b/decnet/ttp/store/impl/database.py
index 0047076c..a4d850f3 100644
--- a/decnet/ttp/store/impl/database.py
+++ b/decnet/ttp/store/impl/database.py
@@ -1,45 +1,273 @@
 """Database-backed rule store — ``ttp_rule`` + ``ttp_rule_state``.
 
-Contract step E.1.11. Bodies raise ``NotImplementedError``; the
-backing tables (:class:`TTPRule`, :class:`TTPRuleState`) shipped at
-E.1.1.
-
-Right for swarm: master syncs filesystem changes into ``ttp_rule``,
-workers tail the DB, state in ``ttp_rule_state`` survives restart and
-propagates to every worker. Pick via
+E.3.6 implementation. Right for swarm: master syncs filesystem changes
+into ``ttp_rule``, workers tail the DB, state in ``ttp_rule_state``
+survives restart and propagates to every worker. Pick via
 ``DECNET_TTP_RULE_STORE_TYPE=database``.
 
 No platform guard — works on macOS / Windows where the filesystem
 backend's inotify dependency is unavailable.
+
+Mechanics:
+
+* :meth:`load_compiled` — read every row of ``ttp_rule``, parse the
+  stored ``yaml_content`` through :class:`RuleSchema`, stamp the
+  matching :class:`RuleState` from ``ttp_rule_state`` (or default
+  ``RuleState`` if no row exists). Malformed YAML in ``yaml_content``
+  raises immediately — same deploy-time-not-runtime asymmetry as the
+  filesystem backend.
+* :meth:`get_state` — single-row lookup against ``ttp_rule_state``
+  with the same ``expires_at`` auto-revert + bus-event semantics as
+  the filesystem store.
+* :meth:`set_state` — upsert into ``ttp_rule_state``; failures raise
+  rather than silently drop. Publishes the change through the
+  in-process subscriber fan-out and (if a bus is wired) the matching
+  ``ttp.rule.state.{rule_id}`` topic.
+* :meth:`subscribe_changes` — async iterator backed by a per-subscriber
+  queue. Direct :meth:`set_state` calls feed the queue synchronously;
+  cross-process changes (master writes a new ``ttp_rule`` row, this
+  worker tails it) are picked up by :meth:`tail_db` — a poll loop the
+  worker bootstrap (E.3.14) wires onto the asyncio event loop.
+
+The master-side filesystem→DB sync helper is
+:meth:`sync_from_filesystem`, which subscribes to a
+:class:`FilesystemRuleStore` and projects its
+:class:`RuleChange` events onto upserts/deletes against ``ttp_rule``.
 """
 from __future__ import annotations
 
+import asyncio
 from collections.abc import AsyncIterator
+from dataclasses import replace
+from datetime import datetime, timezone
+from typing import TYPE_CHECKING, Any, Final
 
-from decnet.ttp.impl.rule_engine import CompiledRule
+import yaml
+from sqlalchemy import delete as sa_delete
+from sqlalchemy import select as sa_select
+from sqlmodel import col
+
+from decnet import telemetry as _telemetry
+from decnet.bus import topics as _topics
+from decnet.bus.publish import publish_safely
+from decnet.logging import get_logger
+from decnet.ttp.impl.rule_engine import CompiledRule, RuleSchema
 from decnet.ttp.store.base import RuleChange, RuleState, RuleStore
+from decnet.web.db.models import TTPRule, TTPRuleState
+
+if TYPE_CHECKING:
+    from decnet.bus.base import BaseBus
+    from decnet.ttp.store.impl.filesystem import FilesystemRuleStore
+    from decnet.web.db.repository import BaseRepository
+
+
+_log = get_logger("ttp.store.database")
+
+
+def _tracer() -> Any:
+    return _telemetry.get_tracer("ttp.store")
+
+
+def _utcnow() -> datetime:
+    return datetime.now(tz=timezone.utc)
+
+
+def _is_expired(state: RuleState, now: datetime) -> bool:
+    if state.expires_at is None:
+        return False
+    expires = state.expires_at
+    if expires.tzinfo is None:
+        expires = expires.replace(tzinfo=timezone.utc)
+    return expires < now
+
+
+def _row_to_state(row: TTPRuleState) -> RuleState:
+    state_value = row.state
+    if state_value not in ("enabled", "disabled", "clipped"):
+        # Pinned at the contract layer so an out-of-band SQL UPDATE
+        # cannot smuggle a bogus state through.
+        raise ValueError(
+            f"ttp_rule_state.state for {row.rule_id!r} is "
+            f"{state_value!r}; must be one of enabled/disabled/clipped",
+        )
+    return RuleState(
+        state=state_value,  # type: ignore[arg-type]
+        confidence_max=row.confidence_max,
+        expires_at=row.expires_at,
+        reason=row.reason,
+        set_by=row.set_by,
+        set_at=row.set_at,
+    )
+
+
+def _safe_set_attrs(span: Any, **attrs: Any) -> None:
+    setter = getattr(span, "set_attribute", None)
+    if setter is None:
+        return
+    for key, value in attrs.items():
+        try:
+            setter(key, value)
+        except (TypeError, ValueError):
+            continue
+
+
+def _compile_one(parsed: RuleSchema, state: RuleState) -> CompiledRule:
+    emits: list[tuple[str, str | None]] = []
+    for entry in parsed.emits:
+        tid = entry.get("technique_id")
+        if not tid:
+            raise ValueError(
+                f"rule {parsed.rule_id}: every emits entry needs technique_id",
+            )
+        sub = entry.get("sub_technique_id") or None
+        emits.append((tid, sub))
+    return CompiledRule(
+        rule_id=parsed.rule_id,
+        rule_version=parsed.rule_version,
+        name=parsed.name,
+        applies_to=frozenset(parsed.applies_to),
+        match_spec=dict(parsed.match),
+        emits=tuple(emits),
+        evidence_fields=tuple(parsed.evidence_fields),
+        state=state,
+    )
+
+
+def _yaml_to_compiled(yaml_text: str, state: RuleState) -> CompiledRule:
+    doc = yaml.safe_load(yaml_text)
+    if not isinstance(doc, dict):
+        raise ValueError(
+            "ttp_rule.yaml_content top-level YAML must be a mapping",
+        )
+    parsed = RuleSchema.model_validate(doc)
+    return _compile_one(parsed, state)
+
+
+def _compiled_to_yaml(compiled: CompiledRule) -> str:
+    """Serialize a :class:`CompiledRule` back to a YAML rule body for
+    master-side filesystem→DB sync. Mirrors :class:`RuleSchema`."""
+    emits: list[dict[str, str]] = []
+    for technique_id, sub in compiled.emits:
+        entry: dict[str, str] = {"technique_id": technique_id}
+        if sub:
+            entry["sub_technique_id"] = sub
+        emits.append(entry)
+    return yaml.safe_dump({
+        "rule_id": compiled.rule_id,
+        "rule_version": compiled.rule_version,
+        "name": compiled.name,
+        "applies_to": sorted(compiled.applies_to),
+        "match": compiled.match_spec,
+        "emits": emits,
+        "evidence_fields": list(compiled.evidence_fields),
+    }, sort_keys=False)
+
+
+class _ChangeIterator:
+    def __init__(
+        self,
+        queue: asyncio.Queue[RuleChange],
+        subscribers: list[asyncio.Queue[RuleChange]],
+    ) -> None:
+        self._queue = queue
+        self._subscribers = subscribers
+
+    def __aiter__(self) -> "_ChangeIterator":
+        return self
+
+    async def __anext__(self) -> RuleChange:
+        return await self._queue.get()
+
+    async def aclose(self) -> None:
+        try:
+            self._subscribers.remove(self._queue)
+        except ValueError:
+            pass
 
 
 class DatabaseRuleStore(RuleStore):
-    """``ttp_rule`` content + ``ttp_rule_state`` operational state.
+    """``ttp_rule`` content + ``ttp_rule_state`` operational state."""
 
-    Contract phase: every method raises ``NotImplementedError``. The
-    impl step (E.3) implements DB-tail subscription + master-side
-    filesystem→DB sync. Worker-side tailing reads via the existing
-    repository pattern; the master's filesystem-watch sync is
-    structurally a delta from :class:`FilesystemRuleStore` plus a
-    ``ttp_rule`` upsert.
-    """
+    def __init__(
+        self,
+        repo: "BaseRepository | None" = None,
+        *,
+        bus: "BaseBus | None" = None,
+    ) -> None:
+        self._repo = repo
+        self._bus = bus
+        self._subscribers: list[asyncio.Queue[RuleChange]] = []
+        self._tail_task: asyncio.Task[None] | None = None
+        self._tail_watermark: datetime | None = None
+        self._sync_task: asyncio.Task[None] | None = None
+        self._stop = asyncio.Event()
+        self._lazy_lock = asyncio.Lock()
+
+    async def _ensure_repo(self) -> "BaseRepository":
+        if self._repo is not None:
+            return self._repo
+        # Lazy in-memory SQLite repo so unit tests that just call
+        # ``DatabaseRuleStore()`` get a usable backend without ceremony.
+        # Production callers always pass an explicit repo via the
+        # worker bootstrap (E.3.14).
+        async with self._lazy_lock:
+            if self._repo is not None:
+                return self._repo
+            from decnet.web.db.sqlite.repository import SQLiteRepository  # noqa: PLC0415
+
+            repo = SQLiteRepository(db_path=":memory:")
+            await repo.initialize()
+            self._repo = repo
+        return self._repo
+
+    # ── ABC methods ─────────────────────────────────────────────────
 
     async def load_compiled(self) -> list[CompiledRule]:
-        raise NotImplementedError(
-            "DatabaseRuleStore.load_compiled lands at E.3",
-        )
+        repo = await self._ensure_repo()
+        async with repo._session() as session:  # type: ignore[attr-defined]
+            rule_rows = (
+                await session.execute(sa_select(TTPRule))
+            ).scalars().all()
+            state_rows = (
+                await session.execute(sa_select(TTPRuleState))
+            ).scalars().all()
+        states: dict[str, RuleState] = {}
+        now = _utcnow()
+        for row in state_rows:
+            cached = _row_to_state(row)
+            if _is_expired(cached, now):
+                cached = RuleState()
+            states[row.rule_id] = cached
+        compiled: list[CompiledRule] = []
+        for rule_row in rule_rows:
+            state = states.get(rule_row.rule_id, RuleState())
+            compiled.append(_yaml_to_compiled(rule_row.yaml_content, state))
+        return compiled
 
     async def get_state(self, rule_id: str) -> RuleState:
-        raise NotImplementedError(
-            "DatabaseRuleStore.get_state lands at E.3",
-        )
+        repo = await self._ensure_repo()
+        async with repo._session() as session:  # type: ignore[attr-defined]
+            row = (
+                await session.execute(
+                    sa_select(TTPRuleState).where(
+                        col(TTPRuleState.rule_id) == rule_id,
+                    ),
+                )
+            ).scalars().first()
+        if row is None:
+            return RuleState()
+        cached = _row_to_state(row)
+        if _is_expired(cached, _utcnow()):
+            # Auto-revert: drop the row, emit the change event.
+            await self._delete_state_row(rule_id)
+            default = RuleState()
+            await self._emit_change(
+                RuleChange("state", rule_id, default),
+                bus_topic=_topics.ttp_rule_state(rule_id),
+                payload={"rule_id": rule_id, "auto_revert": True},
+            )
+            return default
+        return cached
 
     async def set_state(
         self,
@@ -47,14 +275,266 @@ class DatabaseRuleStore(RuleStore):
         state: RuleState,
         set_by: str,
     ) -> None:
-        raise NotImplementedError(
-            "DatabaseRuleStore.set_state lands at E.3",
-        )
+        with _tracer().start_as_current_span("ttp.rule.state.change") as span:
+            _safe_set_attrs(
+                span,
+                rule_id=rule_id,
+                state=state.state,
+                set_by=set_by,
+            )
+            stamped = replace(state, set_by=set_by, set_at=_utcnow())
+            with _tracer().start_as_current_span("ttp.store.write_state"):
+                await self._upsert_state_row(rule_id, stamped)
+            with _tracer().start_as_current_span("ttp.rule.publish"):
+                await self._emit_change(
+                    RuleChange("state", rule_id, stamped),
+                    bus_topic=_topics.ttp_rule_state(rule_id),
+                    payload={
+                        "rule_id": rule_id,
+                        "state": stamped.state,
+                        "set_by": set_by,
+                    },
+                )
 
     def subscribe_changes(self) -> AsyncIterator[RuleChange]:
-        raise NotImplementedError(
-            "DatabaseRuleStore.subscribe_changes lands at E.3",
+        queue: asyncio.Queue[RuleChange] = asyncio.Queue()
+        self._subscribers.append(queue)
+        return _ChangeIterator(queue, self._subscribers)
+
+    # ── Internals: subscriber fan-out ───────────────────────────────
+
+    async def _emit_change(
+        self,
+        change: RuleChange,
+        *,
+        bus_topic: str,
+        payload: dict[str, Any],
+    ) -> None:
+        for queue in list(self._subscribers):
+            await queue.put(change)
+        if self._bus is not None:
+            await publish_safely(self._bus, bus_topic, payload)
+
+    # ── Internals: ttp_rule_state writes ────────────────────────────
+
+    async def _upsert_state_row(
+        self, rule_id: str, state: RuleState,
+    ) -> None:
+        repo = await self._ensure_repo()
+        async with repo._session() as session:  # type: ignore[attr-defined]
+            existing = (
+                await session.execute(
+                    sa_select(TTPRuleState).where(
+                        col(TTPRuleState.rule_id) == rule_id,
+                    ),
+                )
+            ).scalars().first()
+            if existing is None:
+                session.add(
+                    TTPRuleState(
+                        rule_id=rule_id,
+                        state=state.state,
+                        confidence_max=state.confidence_max,
+                        expires_at=state.expires_at,
+                        reason=state.reason,
+                        set_by=state.set_by,
+                        set_at=state.set_at or _utcnow(),
+                    ),
+                )
+            else:
+                existing.state = state.state
+                existing.confidence_max = state.confidence_max
+                existing.expires_at = state.expires_at
+                existing.reason = state.reason
+                existing.set_by = state.set_by
+                existing.set_at = state.set_at or _utcnow()
+                session.add(existing)
+            await session.commit()
+
+    async def _delete_state_row(self, rule_id: str) -> None:
+        repo = await self._ensure_repo()
+        async with repo._session() as session:  # type: ignore[attr-defined]
+            await session.execute(
+                sa_delete(TTPRuleState).where(
+                    col(TTPRuleState.rule_id) == rule_id,
+                ),
+            )
+            await session.commit()
+
+    # ── ttp_rule writes (master-side filesystem sync) ───────────────
+
+    async def upsert_rule(
+        self,
+        compiled: CompiledRule,
+        *,
+        source_path: str,
+        updated_by: str,
+    ) -> None:
+        """Master-side: write a rule definition into ``ttp_rule``.
+
+        Workers tailing the DB pick up the change via :meth:`tail_db`
+        and emit ``RuleChange("definition", ...)`` events to local
+        engines. Used by :meth:`sync_from_filesystem`.
+        """
+        repo = await self._ensure_repo()
+        yaml_text = _compiled_to_yaml(compiled)
+        async with repo._session() as session:  # type: ignore[attr-defined]
+            existing = (
+                await session.execute(
+                    sa_select(TTPRule).where(
+                        col(TTPRule.rule_id) == compiled.rule_id,
+                    ),
+                )
+            ).scalars().first()
+            now = _utcnow()
+            if existing is None:
+                session.add(TTPRule(
+                    rule_id=compiled.rule_id,
+                    rule_version=compiled.rule_version,
+                    source_path=source_path,
+                    yaml_content=yaml_text,
+                    updated_at=now,
+                    updated_by=updated_by,
+                ))
+            else:
+                existing.rule_version = compiled.rule_version
+                existing.source_path = source_path
+                existing.yaml_content = yaml_text
+                existing.updated_at = now
+                existing.updated_by = updated_by
+                session.add(existing)
+            await session.commit()
+        await self._emit_change(
+            RuleChange("definition", compiled.rule_id, compiled),
+            bus_topic=_topics.ttp_rule_reloaded(compiled.rule_id),
+            payload={
+                "rule_id": compiled.rule_id,
+                "rule_version": compiled.rule_version,
+            },
         )
 
+    async def delete_rule(self, rule_id: str) -> None:
+        repo = await self._ensure_repo()
+        async with repo._session() as session:  # type: ignore[attr-defined]
+            await session.execute(
+                sa_delete(TTPRule).where(col(TTPRule.rule_id) == rule_id),
+            )
+            await session.commit()
+        await self._emit_change(
+            RuleChange("definition", rule_id, _DELETED_SENTINEL),
+            bus_topic=_topics.ttp_rule_reloaded(rule_id),
+            payload={"rule_id": rule_id, "deleted": True},
+        )
+
+    # ── Master: filesystem→DB sync ──────────────────────────────────
+
+    async def sync_from_filesystem(
+        self,
+        fs_store: "FilesystemRuleStore",
+        *,
+        updated_by: str = "filesystem",
+    ) -> None:
+        """Subscribe to a :class:`FilesystemRuleStore` and project its
+        ``RuleChange`` events onto ``ttp_rule`` upserts/deletes.
+
+        Runs forever; the caller (the master worker bootstrap E.3.14)
+        cancels it during shutdown. Definition deletes (the FS store
+        emits a sentinel ``CompiledRule`` with empty emits) project
+        onto a ``ttp_rule`` row delete.
+        """
+        async for change in fs_store.subscribe_changes():
+            try:
+                if change.change_kind != "definition":
+                    continue
+                value = change.new_value
+                if not isinstance(value, CompiledRule):
+                    continue
+                if not value.emits and not value.applies_to:
+                    await self.delete_rule(change.rule_id)
+                else:
+                    await self.upsert_rule(
+                        value,
+                        source_path=f"./rules/ttp/{change.rule_id}.yaml",
+                        updated_by=updated_by,
+                    )
+            except Exception:  # noqa: BLE001
+                _log.exception(
+                    "ttp.store.db: master sync failed rule_id=%s",
+                    change.rule_id,
+                )
+
+    # ── Worker: DB-tail polling ─────────────────────────────────────
+
+    async def tail_db(self, *, poll_interval: float = 1.0) -> None:
+        """Poll ``ttp_rule.updated_at`` past a watermark; emit
+        :class:`RuleChange` events for each row that moved.
+
+        Used by worker bootstrap (E.3.14) so a swarm of workers each
+        receive per-rule definition changes without a shared bus
+        round-trip. The watermark advances on every observed row;
+        first poll initializes it to "now" so we don't replay history.
+        """
+        repo = await self._ensure_repo()
+        if self._tail_watermark is None:
+            self._tail_watermark = _utcnow()
+        while not self._stop.is_set():
+            try:
+                async with repo._session() as session:  # type: ignore[attr-defined]
+                    rows = (
+                        await session.execute(
+                            sa_select(TTPRule).where(
+                                col(TTPRule.updated_at) > self._tail_watermark,
+                            ),
+                        )
+                    ).scalars().all()
+                for rule_row in rows:
+                    state = await self.get_state(rule_row.rule_id)
+                    compiled = _yaml_to_compiled(rule_row.yaml_content, state)
+                    await self._emit_change(
+                        RuleChange("definition", compiled.rule_id, compiled),
+                        bus_topic=_topics.ttp_rule_reloaded(compiled.rule_id),
+                        payload={
+                            "rule_id": compiled.rule_id,
+                            "rule_version": compiled.rule_version,
+                        },
+                    )
+                    if (
+                        self._tail_watermark is None
+                        or rule_row.updated_at > self._tail_watermark
+                    ):
+                        self._tail_watermark = rule_row.updated_at
+            except Exception:  # noqa: BLE001
+                _log.exception("ttp.store.db: tail poll failed")
+            try:
+                await asyncio.wait_for(
+                    self._stop.wait(), timeout=poll_interval,
+                )
+            except asyncio.TimeoutError:
+                continue
+
+    async def stop(self) -> None:
+        self._stop.set()
+        for task in (self._tail_task, self._sync_task):
+            if task is not None:
+                task.cancel()
+                try:
+                    await task
+                except (asyncio.CancelledError, Exception):  # noqa: BLE001
+                    pass
+        self._tail_task = None
+        self._sync_task = None
+
+
+_DELETED_SENTINEL: Final[CompiledRule] = CompiledRule(
+    rule_id="",
+    rule_version=0,
+    name="",
+    applies_to=frozenset(),
+    match_spec={},
+    emits=(),
+    evidence_fields=(),
+    state=RuleState(),
+)
+
 
 __all__ = ["DatabaseRuleStore"]
diff --git a/decnet/ttp/store/impl/filesystem.py b/decnet/ttp/store/impl/filesystem.py
index d4b0013e..2c19721b 100644
--- a/decnet/ttp/store/impl/filesystem.py
+++ b/decnet/ttp/store/impl/filesystem.py
@@ -50,10 +50,10 @@ from typing import TYPE_CHECKING, Any, Final, Type
 
 import yaml
 
+from decnet import telemetry as _telemetry
 from decnet.bus import topics as _topics
 from decnet.bus.publish import publish_safely
 from decnet.logging import get_logger
-from decnet.telemetry import get_tracer
 from decnet.ttp.impl.rule_engine import CompiledRule, RuleSchema
 from decnet.ttp.store.base import RuleChange, RuleState, RuleStore
 
@@ -62,7 +62,13 @@ if TYPE_CHECKING:
 
 
 _log = get_logger("ttp.store.filesystem")
-_tracer = get_tracer("ttp.store")
+
+
+def _tracer() -> Any:
+    # Late binding: tests monkeypatch ``decnet.telemetry.get_tracer``
+    # at fixture setup; capturing the tracer at import time would freeze
+    # the no-op tracer into the module forever.
+    return _telemetry.get_tracer("ttp.store")
 
 
 # ── Filename allowlist ──────────────────────────────────────────────
@@ -324,7 +330,7 @@ class FilesystemRuleStore(RuleStore):
         # Operational state changes are NOT a tolerated-absence path.
         # Failures here MUST raise rather than silently drop — the
         # E.2.14b conformance test pins this.
-        with _tracer.start_as_current_span("ttp.rule.state.change") as span:
+        with _tracer().start_as_current_span("ttp.rule.state.change") as span:
             # Defensive set_attribute: real OTEL spans accept str/int/etc;
             # the no-op tracer's _NoOpSpan ignores attributes silently. A
             # caller-side wrapper keeps both paths green without leaking
@@ -336,10 +342,10 @@ class FilesystemRuleStore(RuleStore):
                 set_by=set_by,
             )
             stamped = replace(state, set_by=set_by, set_at=_utcnow())
-            with _tracer.start_as_current_span("ttp.store.write_state"):
+            with _tracer().start_as_current_span("ttp.store.write_state"):
                 self._state[rule_id] = stamped
                 self._restamp_compiled(rule_id, stamped)
-            with _tracer.start_as_current_span("ttp.rule.publish"):
+            with _tracer().start_as_current_span("ttp.rule.publish"):
                 await self._emit_change(
                     RuleChange("state", rule_id, stamped),
                     bus_topic=_topics.ttp_rule_state(rule_id),
diff --git a/development/TTP_TAGGING.md b/development/TTP_TAGGING.md
index 37bc2745..fed90c82 100644
--- a/development/TTP_TAGGING.md
+++ b/development/TTP_TAGGING.md
@@ -2944,7 +2944,13 @@ Order:
    variant. `ttp_rule` and `ttp_rule_state` tables created via
    SQLModel. Master-side filesystem→DB sync. Worker-side DB
    tail. Conformance tests green on both backends in parallel
-   (filesystem vs database) using the parametrized fixture.
+   (filesystem vs database) using the parametrized fixture. ✅ done.
+   Lazy in-memory SQLite repo for unconfigured construction (so
+   the conformance fixture works without test plumbing).
+   `sync_from_filesystem(fs_store)` master helper subscribes to a
+   `FilesystemRuleStore` and projects each `RuleChange` onto a
+   `ttp_rule` upsert/delete; `tail_db()` is the worker-side
+   watermark poll.
 7. **RuleEngine** — implement engine consuming from `RuleStore`.
    Atomic per-rule swap on `RuleChange`. State applied
    after-parsing via `RuleState` join. `test_rule_engine.py`
diff --git a/tests/ttp/store/conftest.py b/tests/ttp/store/conftest.py
index 5a218cf8..95387602 100644
--- a/tests/ttp/store/conftest.py
+++ b/tests/ttp/store/conftest.py
@@ -14,29 +14,74 @@ from __future__ import annotations
 
 import sys
 from pathlib import Path
-from typing import Iterator
+from typing import AsyncIterator
 
 import pytest
+import pytest_asyncio
 
 from decnet.ttp.store.base import RuleStore
 from decnet.ttp.store.impl.database import DatabaseRuleStore
 from decnet.ttp.store.impl.filesystem import FilesystemRuleStore
+from decnet.web.db.models import TTPRule
 
 
-@pytest.fixture(
+async def _seed_rule_filesystem(
+    store: FilesystemRuleStore, rule_id: str, yaml_text: str,
+) -> None:
+    rules_dir: Path = store._rules_dir
+    rules_dir.mkdir(parents=True, exist_ok=True)
+    (rules_dir / f"{rule_id}.yaml").write_text(yaml_text, encoding="utf-8")
+
+
+async def _seed_rule_database(
+    store: DatabaseRuleStore, rule_id: str, yaml_text: str,
+) -> None:
+    # Direct ``ttp_rule`` insert — bypass the master sync helper to
+    # keep tests deterministic. Mirrors what a swarm master would have
+    # written into the table.
+    repo = await store._ensure_repo()
+    async with repo._session() as session:  # type: ignore[attr-defined]
+        from datetime import datetime, timezone  # noqa: PLC0415
+
+        session.add(TTPRule(
+            rule_id=rule_id,
+            rule_version=1,
+            source_path=f"./rules/ttp/{rule_id}.yaml",
+            yaml_content=yaml_text,
+            updated_at=datetime.now(timezone.utc),
+            updated_by="test",
+        ))
+        await session.commit()
+
+
+async def seed_rule(store: RuleStore, rule_id: str, yaml_text: str) -> None:
+    """Backend-aware test helper: write a rule into the store.
+
+    Filesystem store: drop a YAML file under ``_rules_dir``.
+    Database store: insert a ``ttp_rule`` row directly.
+    """
+    if isinstance(store, FilesystemRuleStore):
+        await _seed_rule_filesystem(store, rule_id, yaml_text)
+    elif isinstance(store, DatabaseRuleStore):
+        await _seed_rule_database(store, rule_id, yaml_text)
+    else:  # pragma: no cover
+        raise TypeError(f"unknown rule store backend: {type(store).__name__}")
+
+
+@pytest_asyncio.fixture(
     params=["filesystem", "database"],
     ids=["filesystem", "database"],
 )
-def rule_store(
+async def rule_store(
     request: pytest.FixtureRequest, tmp_path: Path,
-) -> Iterator[RuleStore]:
+) -> AsyncIterator[RuleStore]:
     """Yield a fresh :class:`RuleStore` instance per parametrization.
 
     The filesystem backend is constructed against a ``tmp_path``
     rules dir so tests never touch the real ``./rules/``. The
-    database backend's connection wiring lands at E.3.6; today the
-    fixture just hands out the raw class instance and impl-phase
-    tests are responsible for plumbing it into a session.
+    database backend gets a per-test SQLite repo (initialized with
+    ``metadata.create_all``) so each test sees an empty
+    ``ttp_rule`` / ``ttp_rule_state`` pair.
     """
     backend = request.param
     if backend == "filesystem":
@@ -44,4 +89,20 @@ def rule_store(
             pytest.skip("FilesystemRuleStore requires Linux (inotify)")
         yield FilesystemRuleStore(rules_dir=tmp_path)
     else:
-        yield DatabaseRuleStore()
+        from decnet.web.db.sqlite.repository import SQLiteRepository  # noqa: PLC0415
+
+        repo = SQLiteRepository(db_path=str(tmp_path / "ttp_store.db"))
+        await repo.initialize()
+        store = DatabaseRuleStore(repo=repo)
+        # Mirror FS store's ``_rules_dir`` attr so cross-backend tests
+        # that need to drop sample YAML on disk have somewhere to put
+        # it; the DB-backend tests that need rule definitions either
+        # write to ``ttp_rule`` directly or call ``upsert_rule``.
+        store._rules_dir = tmp_path  # type: ignore[attr-defined]
+        try:
+            yield store
+        finally:
+            try:
+                await repo.engine.dispose()
+            except Exception:  # noqa: BLE001 — teardown best-effort
+                pass
diff --git a/tests/ttp/store/test_conformance.py b/tests/ttp/store/test_conformance.py
index 0e7ef154..5d2d50af 100644
--- a/tests/ttp/store/test_conformance.py
+++ b/tests/ttp/store/test_conformance.py
@@ -40,6 +40,8 @@ import pytest
 from decnet.ttp.impl.rule_engine import CompiledRule
 from decnet.ttp.store.base import RuleChange, RuleState, RuleStore
 
+from .conftest import seed_rule
+
 
 _RULE_YAML = """\
 rule_id: {rule_id}
@@ -53,18 +55,6 @@ emits:
 """
 
 
-def _xfail_db_until_e36(rule_store: RuleStore) -> None:
-    """Skip a parametrized run for the database backend.
-
-    The conformance contract is identical across backends, but the
-    DB backend's persistence path lands at E.3.6. Per-test xfail
-    rather than a module-level skip so the FS-backend run still
-    exercises the assertion today.
-    """
-    if type(rule_store).__name__ == "DatabaseRuleStore":
-        pytest.xfail("impl phase E.3.6 — DatabaseRuleStore not implemented")
-
-
 # ── Surface (GREEN today) ───────────────────────────────────────────
 
 
@@ -99,14 +89,7 @@ def test_rule_change_namedtuple_shape() -> None:
 
 async def test_get_state_unknown_returns_default(rule_store: RuleStore) -> None:
     """``get_state`` for a never-set ``rule_id`` returns the default
-    ``RuleState`` — never raises, never returns ``None``.
-
-    GREEN for :class:`FilesystemRuleStore` (the impl already returns
-    ``RuleState()`` for an empty cache; covered in the contract
-    file). xfail for :class:`DatabaseRuleStore` until E.3.6 lands.
-    """
-    if type(rule_store).__name__ == "DatabaseRuleStore":
-        pytest.xfail("impl phase E.3.6 — DatabaseRuleStore.get_state")
+    ``RuleState`` — never raises, never returns ``None``."""
     state = await rule_store.get_state("R0001_unknown_rule")
     assert state == RuleState()
     assert state.state == "enabled"
@@ -123,14 +106,8 @@ async def test_load_compiled_corpus_identical_across_backends(
     cross-backend property requires running the same fixture against
     both — pinned here as a single test that the parametrize fans
     out over both backends."""
-    _xfail_db_until_e36(rule_store)
-    rules_dir: Path = rule_store._rules_dir  # type: ignore[attr-defined]
-    (rules_dir / "R0001.yaml").write_text(
-        _RULE_YAML.format(rule_id="R0001"), encoding="utf-8",
-    )
-    (rules_dir / "R0002.yaml").write_text(
-        _RULE_YAML.format(rule_id="R0002"), encoding="utf-8",
-    )
+    await seed_rule(rule_store, "R0001", _RULE_YAML.format(rule_id="R0001"))
+    await seed_rule(rule_store, "R0002", _RULE_YAML.format(rule_id="R0002"))
     compiled = await rule_store.load_compiled()
     assert {c.rule_id for c in compiled} == {"R0001", "R0002"}
     for c in compiled:
@@ -143,7 +120,6 @@ async def test_load_compiled_corpus_identical_across_backends(
 async def test_set_state_isolates_rules(rule_store: RuleStore) -> None:
     """``set_state(A, ...)`` does not perturb the state read by
     ``get_state(B)``."""
-    _xfail_db_until_e36(rule_store)
     await rule_store.set_state(
         "R0001", RuleState(state="disabled", reason="A"), set_by="op",
     )
@@ -156,7 +132,6 @@ async def test_set_state_then_get_state_round_trips(
 ) -> None:
     """``set_state`` followed by ``get_state`` returns the value
     that was set. No translation, no field drop."""
-    _xfail_db_until_e36(rule_store)
     new_state = RuleState(
         state="clipped", confidence_max=0.5, reason="probation",
     )
@@ -177,7 +152,6 @@ async def test_subscribe_changes_per_rule_not_batched(
     entries. The bus per-rule fan-out
     (``ttp.rule.reloaded.{rule_id}``) inherits its granularity from
     this iterator."""
-    _xfail_db_until_e36(rule_store)
     sub = rule_store.subscribe_changes()
     for i in range(5):
         await rule_store.set_state(
@@ -199,7 +173,6 @@ async def test_expired_state_reverts_to_default_and_emits(
     """A ``RuleState`` with ``expires_at`` in the past returns the
     default from :meth:`get_state` AND emits a
     ``ttp.rule.state.{rule_id}`` auto-revert event."""
-    _xfail_db_until_e36(rule_store)
     past = datetime.now(tz=timezone.utc) - timedelta(seconds=5)
     sub = rule_store.subscribe_changes()
     await rule_store.set_state(
@@ -224,7 +197,6 @@ async def test_set_state_failure_raises_not_silent(
     death) MUST raise rather than silently drop. Operational state
     changes are NOT a tolerated-absence path — state drift would be
     silent and dangerous."""
-    _xfail_db_until_e36(rule_store)
 
     class _BoomQueue:
         async def put(self, _item: object) -> None:
diff --git a/tests/ttp/store/test_database.py b/tests/ttp/store/test_database.py
index 1f735e57..cbc4549f 100644
--- a/tests/ttp/store/test_database.py
+++ b/tests/ttp/store/test_database.py
@@ -2,8 +2,7 @@
 
 Per ``development/TTP_TAGGING.md`` §E.2.14b: the database backend's
 tests run against BOTH SQLite and MySQL via the ``db_backends``
-fixture in :mod:`tests.web.db.conftest`. Today the database store's
-methods raise ``NotImplementedError`` so most assertions xfail.
+fixture in :mod:`tests.web.db.conftest`.
 
 The cross-backend conformance assertions (load_compiled equality,
 get_state default, set_state isolation/round-trip,
@@ -13,16 +12,26 @@ via the parametrized ``rule_store`` fixture in :mod:`conftest`.
 
 This module pins behavior that's *only* meaningful for the database
 backend — specifically the propagation of state via the underlying
-``ttp_rule_state`` table, which conformance tests exercise but don't
-introspect at the SQL level.
+``ttp_rule_state`` table and the master-side filesystem→DB sync
+helper.
 """
 from __future__ import annotations
 
 import inspect
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
 
 import pytest
+import pytest_asyncio
 
+from decnet.ttp.impl.rule_engine import CompiledRule
+from decnet.ttp.store.base import RuleState
 from decnet.ttp.store.impl.database import DatabaseRuleStore
+from decnet.web.db.models import TTPRule, TTPRuleState
+from sqlalchemy import select as sa_select
+from sqlmodel import col
 
 
 def test_database_store_constructs_without_platform_guard() -> None:
@@ -52,29 +61,148 @@ def test_async_methods_are_coroutines() -> None:
         assert inspect.iscoroutinefunction(member)
 
 
-@pytest.mark.xfail(
-    strict=True,
-    reason="impl phase E.3.6 — DatabaseRuleStore needs to write "
-    "into ttp_rule_state via the repository session; today the "
-    "method body raises NotImplementedError",
-)
-async def test_set_state_writes_to_ttp_rule_state_table() -> None:
+@pytest_asyncio.fixture
+async def db_store(tmp_path: Path) -> Any:
+    from decnet.web.db.sqlite.repository import SQLiteRepository
+
+    repo = SQLiteRepository(db_path=str(tmp_path / "ttp_db_store.db"))
+    await repo.initialize()
+    store = DatabaseRuleStore(repo=repo)
+    try:
+        yield store
+    finally:
+        try:
+            await repo.engine.dispose()
+        except Exception:  # noqa: BLE001
+            pass
+
+
+async def test_set_state_writes_to_ttp_rule_state_table(
+    db_store: DatabaseRuleStore, tmp_path: Path,
+) -> None:
     """``set_state`` writes / upserts a row in the ``ttp_rule_state``
-    table. After the write, a fresh ``DatabaseRuleStore`` instance
-    sees the same value via :meth:`get_state` (state survives
-    process restart — that's the whole point of the database
-    backend over the filesystem one)."""
-    pytest.fail("DatabaseRuleStore.set_state not yet implemented")
+    table. After the write, a fresh :class:`DatabaseRuleStore`
+    instance pointing at the same DB sees the same value via
+    :meth:`get_state` — state survives process restart, which is the
+    whole point of the DB backend over the filesystem one."""
+    await db_store.set_state(
+        "R0001",
+        RuleState(state="disabled", reason="probation"),
+        set_by="anti",
+    )
+    repo = db_store._repo
+    assert repo is not None
+    async with repo._session() as session:  # type: ignore[attr-defined]
+        row = (
+            await session.execute(
+                sa_select(TTPRuleState).where(
+                    col(TTPRuleState.rule_id) == "R0001",
+                ),
+            )
+        ).scalars().first()
+    assert row is not None
+    assert row.state == "disabled"
+    assert row.reason == "probation"
+    assert row.set_by == "anti"
+
+    # Fresh store instance against the same engine — state survives.
+    fresh = DatabaseRuleStore(repo=repo)
+    state = await fresh.get_state("R0001")
+    assert state.state == "disabled"
+    assert state.reason == "probation"
 
 
-@pytest.mark.xfail(
-    strict=True,
-    reason="impl phase E.3.6 — master-side filesystem→DB sync of "
-    "ttp_rule lands with the swarm-mode wiring",
-)
-async def test_filesystem_to_db_sync_populates_ttp_rule() -> None:
+async def test_filesystem_to_db_sync_populates_ttp_rule(
+    db_store: DatabaseRuleStore, tmp_path: Path,
+) -> None:
     """In swarm mode, the master watches ``./rules/ttp/`` and
     syncs each YAML edit into the ``ttp_rule`` table; workers
     tail the DB. This test pins the half of the contract that
-    only the database backend implements."""
-    pytest.fail("master-side fs→DB sync not yet implemented")
+    only the database backend implements: a CompiledRule fed to
+    :meth:`upsert_rule` lands as a ``ttp_rule`` row whose
+    ``yaml_content`` round-trips through :meth:`load_compiled`."""
+    compiled = CompiledRule(
+        rule_id="R0001",
+        rule_version=1,
+        name="brute force ssh",
+        applies_to=frozenset({"command"}),
+        match_spec={"pattern": "hydra"},
+        emits=(("T1110", None),),
+        evidence_fields=("matched_tokens",),
+        state=RuleState(),
+    )
+    await db_store.upsert_rule(
+        compiled,
+        source_path="./rules/ttp/R0001.yaml",
+        updated_by="filesystem",
+    )
+    repo = db_store._repo
+    assert repo is not None
+    async with repo._session() as session:  # type: ignore[attr-defined]
+        row = (
+            await session.execute(
+                sa_select(TTPRule).where(col(TTPRule.rule_id) == "R0001"),
+            )
+        ).scalars().first()
+    assert row is not None
+    assert row.rule_version == 1
+    assert row.updated_by == "filesystem"
+    # Round-trip through load_compiled.
+    loaded = await db_store.load_compiled()
+    assert len(loaded) == 1
+    assert loaded[0].rule_id == "R0001"
+    assert loaded[0].emits == (("T1110", None),)
+
+
+@pytest.mark.skipif(
+    sys.platform != "linux",
+    reason="FilesystemRuleStore is Linux-only (inotify dep)",
+)
+async def test_sync_from_filesystem_propagates_changes(
+    db_store: DatabaseRuleStore, tmp_path: Path,
+) -> None:
+    """The master-side helper :meth:`sync_from_filesystem` projects
+    every :class:`RuleChange` from a :class:`FilesystemRuleStore`
+    onto a ``ttp_rule`` upsert. Validates the swarm-mode
+    bootstrap path: master watches disk, workers tail DB."""
+    import asyncio  # noqa: PLC0415
+    from decnet.ttp.store.impl.filesystem import FilesystemRuleStore  # noqa: PLC0415
+
+    rules_dir = tmp_path / "rules"
+    rules_dir.mkdir()
+    fs_store = FilesystemRuleStore(rules_dir=rules_dir)
+
+    sync_task = asyncio.create_task(
+        db_store.sync_from_filesystem(fs_store, updated_by="git"),
+    )
+    try:
+        async with fs_store:
+            await asyncio.sleep(0.05)
+            (rules_dir / "R0042.yaml").write_text(
+                """rule_id: R0042
+rule_version: 1
+name: test
+applies_to: [command]
+match:
+  pattern: 'whoami'
+emits:
+  - technique_id: T1033
+""",
+                encoding="utf-8",
+            )
+            # Give the sync task a moment to project the change.
+            for _ in range(20):
+                await asyncio.sleep(0.05)
+                loaded = await db_store.load_compiled()
+                if any(c.rule_id == "R0042" for c in loaded):
+                    break
+            else:
+                pytest.fail("sync_from_filesystem did not project the edit")
+            ids = {c.rule_id for c in loaded}
+            assert "R0042" in ids
+    finally:
+        sync_task.cancel()
+        try:
+            await sync_task
+        except (asyncio.CancelledError, Exception):  # noqa: BLE001
+            pass
diff --git a/tests/ttp/test_tracing.py b/tests/ttp/test_tracing.py
index cb8e3c3c..231445b8 100644
--- a/tests/ttp/test_tracing.py
+++ b/tests/ttp/test_tracing.py
@@ -159,16 +159,38 @@ def test_rule_fire_spans_carry_rule_and_technique_attrs(
 # ── set_state span hierarchy (xfail until E.3.5/E.3.6) ──────────────
 
 
-@pytest.mark.xfail(
-    strict=True,
-    reason="impl phase E.3.5/E.3.6 — set_state() span hierarchy lands "
-    "with the rule-store implementations",
-)
-def test_set_state_span_hierarchy(span_exporter: tuple[InMemorySpanExporter, TracerProvider]) -> None:
+def test_set_state_span_hierarchy(
+    span_exporter: tuple[InMemorySpanExporter, TracerProvider],
+) -> None:
     """``RuleStore.set_state`` produces a ``ttp.rule.state.change``
     parent with ``ttp.store.write_state`` + ``ttp.rule.publish``
     children — operator state changes are auditable."""
-    pytest.fail("set_state spans not yet emitted")
+    import asyncio
+    import sys
+
+    if sys.platform != "linux":  # pragma: no cover
+        pytest.skip("FilesystemRuleStore is Linux-only (inotify dep)")
+
+    from decnet.ttp.store.base import RuleState
+    from decnet.ttp.store.impl.filesystem import FilesystemRuleStore
+
+    exporter, _provider = span_exporter
+
+    async def _run() -> None:
+        import tempfile
+
+        with tempfile.TemporaryDirectory() as td:
+            from pathlib import Path
+            store = FilesystemRuleStore(rules_dir=Path(td))
+            await store.set_state(
+                "R0001", RuleState(state="disabled"), set_by="anti",
+            )
+
+    asyncio.run(_run())
+    names = [span.name for span in exporter.get_finished_spans()]
+    assert "ttp.rule.state.change" in names
+    assert "ttp.store.write_state" in names
+    assert "ttp.rule.publish" in names
 
 
 # ── No-PII property (xfail until E.3.7+) ────────────────────────────