convertcom · usmanabbas7 · Apr 20, 2026 · Apr 14, 2026 · Apr 14, 2026 · Apr 14, 2026
diff --git a/scripts/generate_parity_fixtures.py b/scripts/generate_parity_fixtures.py
diff --git a/src/convert_sdk/__init__.py b/src/convert_sdk/__init__.py
@@ -20,6 +20,8 @@
     TrackingError,
 )
 from .events import LifecycleEvent, LifecycleEventPayload
+from .adapters.storage import InMemoryDataStore
+from .ports.storage import DataStore
 from .version import __version__
 
 __all__ = [
@@ -30,10 +32,12 @@
     "Core",
     "ConversionEvent",
     "ConversionResult",
+    "DataStore",
     "ExperienceResult",
     "FeatureResult",
     "FeatureStatus",
     "GoalNotFoundError",
+    "InMemoryDataStore",
     "InitializationError",
     "LifecycleEvent",
     "LifecycleEventPayload",

diff --git a/src/convert_sdk/adapters/storage/__init__.py b/src/convert_sdk/adapters/storage/__init__.py
@@ -0,0 +1,5 @@
+"""Storage adapter implementations."""
+
+from .in_memory import InMemoryDataStore
+
+__all__ = ["InMemoryDataStore"]
diff --git a/src/convert_sdk/adapters/storage/in_memory.py b/src/convert_sdk/adapters/storage/in_memory.py
@@ -0,0 +1,33 @@
+"""Default in-memory persistence adapter for visitor-linked SDK state."""
+
+from __future__ import annotations
+
+from threading import Lock
+
+from ...domain.context_state import ContextState
+from ...ports.storage import DataStore
+
+
+class InMemoryDataStore(DataStore):
+    """Thread-safe process-local visitor state store for MVP behavior."""
+
+    def __init__(self) -> None:
+        self._context_states: dict[str, ContextState] = {}
+        self._tracked_goals: set[tuple[str, str]] = set()
+        self._lock = Lock()
+
+    def load_context_state(self, visitor_id: str) -> ContextState | None:
+        with self._lock:
+            return self._context_states.get(visitor_id)
+
+    def save_context_state(self, state: ContextState) -> None:
+        with self._lock:
+            self._context_states[state.visitor_id] = state
+
+    def has_tracked_goal(self, visitor_id: str, goal_id: str) -> bool:
+        with self._lock:
+            return (visitor_id, goal_id) in self._tracked_goals
+
+    def mark_tracked_goal(self, visitor_id: str, goal_id: str) -> None:
+        with self._lock:
+            self._tracked_goals.add((visitor_id, goal_id))
diff --git a/src/convert_sdk/config_loader/loader.py b/src/convert_sdk/config_loader/loader.py
@@ -2,20 +2,37 @@
 
 from __future__ import annotations
 
+import logging
+
 from .normalizer import build_snapshot
 from .validators import validate_config_data, validate_sdk_config
 from ..config import SDKConfig
+from ..diagnostics import config_source, log_diagnostic_event, snapshot_entity_counts
 from ..domain.config_snapshot import ConfigSnapshot
 from ..errors import ConfigLoadError
 from ..ports.transport import ConfigRequest, Transport
 
 
 def load_config_snapshot(config: SDKConfig, transport: Transport) -> ConfigSnapshot:
+    source = config_source(config.config_data, config.sdk_key)
+    log_diagnostic_event(
+        "config.load.started",
+        source=source,
+        has_environment=bool(config.environment),
+    )
     validate_sdk_config(config)
 
     if config.config_data is not None:
         validate_config_data(config.config_data)
-        return build_snapshot(config.config_data)
+        snapshot = build_snapshot(config.config_data)
+        log_diagnostic_event(
+            "config.load.succeeded",
+            source=source,
+            has_account_id=snapshot.account_id is not None,
+            has_project_id=snapshot.project_id is not None,
+            entity_counts=snapshot_entity_counts(snapshot),
+        )
+        return snapshot
 
     request = ConfigRequest(
         sdk_key=config.sdk_key or "",
@@ -27,9 +44,23 @@ def load_config_snapshot(config: SDKConfig, transport: Transport) -> ConfigSnaps
     try:
         config_data = transport.fetch_config(request)
     except Exception as exc:  # noqa: BLE001
+        log_diagnostic_event(
+            "config.load.failed",
+            level=logging.WARNING,
+            source=source,
+            error_type=type(exc).__name__,
+        )
         raise ConfigLoadError(
             f"Config fetch failed for sdk_key '{config.sdk_key}'"
         ) from exc
 
     validate_config_data(config_data)
-    return build_snapshot(config_data)
+    snapshot = build_snapshot(config_data)
+    log_diagnostic_event(
+        "config.load.succeeded",
+        source=source,
+        has_account_id=snapshot.account_id is not None,
+        has_project_id=snapshot.project_id is not None,
+        entity_counts=snapshot_entity_counts(snapshot),
+    )
+    return snapshot