diff --git a/docs/long-term-plans/sync-core-extraction-plan.md b/docs/long-term-plans/sync-core-extraction-plan.md
index 5719d5218a..2eeddc84e2 100644
--- a/docs/long-term-plans/sync-core-extraction-plan.md
+++ b/docs/long-term-plans/sync-core-extraction-plan.md
@@ -1,9 +1,9 @@
 # `@sp/sync-core` Extraction Plan
 
 > **Status: In progress - PR 1, PR 2 guardrails/logger adapter work, PR 3a
-> vector-clock ownership, and the PR 3b pure helper slices are present on this
-> branch. Remaining PR 2 cleanup is PR text alignment plus targeted future
-> `SyncLogger` routing for files as they move.**
+> vector-clock ownership, full-state op classification config, and the PR 3b
+> pure helper slices are present on this branch. Remaining cleanup is PR text
+> alignment plus targeted future `SyncLogger` routing for files as they move.**
 
 **Goal:** Carve the sync engine out of `src/app/op-log/` into a reusable,
 framework-agnostic, **domain-agnostic** `@sp/sync-core` package, plus a sibling
@@ -103,15 +103,22 @@ groundwork:
 - `eslint.config.js` applies `no-restricted-imports` and a dynamic-import ban to
   `packages/sync-core/**/*.ts`.
 - The package currently exports operation primitives, apply types, LWW helper
-  factory, entity-key helpers, `SyncStateCorruptedError`, entity-registry
-  contracts, and the privacy-aware logger port.
+  factory, full-state op-type helper factory, entity-key helpers,
+  `SyncStateCorruptedError`, entity-registry contracts, and the privacy-aware
+  logger port.
 - The app registry now has `buildEntityRegistry()` and an `ENTITY_REGISTRY`
   injection token. Existing helper functions still read the app-side
   `ENTITY_CONFIGS` singleton for compatibility.
 
 Current extraction state and remaining immediate debt:
 
-- `FULL_STATE_OP_TYPES` still lives in `@sp/sync-core` as compatibility debt.
+- Full-state operation classification is now host-configured via
+  `createFullStateOpTypeHelpers()`. The SP-facing
+  `src/app/op-log/core/operation.types.ts` shim instantiates its own
+  `FULL_STATE_OP_TYPES` and `isFullStateOpType`; the package root keeps
+  deprecated SP compatibility exports for existing consumers. `OpType.SyncImport`,
+  `OpType.BackupImport`, and `OpType.Repair` remain in `@sp/sync-core` only as
+  host-defined compatibility strings.
 - Vector-clock compare/merge/prune now lives in `@sp/sync-core`, with
   `@sp/shared-schema` re-exporting it for existing client/server imports.
 - `SyncLogger` exists, but movable app code still mostly calls `OpLog` directly.
@@ -137,14 +144,12 @@ Current extraction state and remaining immediate debt:
 Suggested next order:
 
 1. Finish PR 2 documentation and verification.
-2. Add the app-side `SyncLogger` adapter before moving `OpLog`-using files.
+2. Continue targeted `SyncLogger` routing for files as they become movable.
 3. Treat the PR 3b pure conflict-resolution and sync-import slices as complete
    for this round.
-4. Make full-state operation classification configurable or explicitly mark
-   those op types as host-defined compatibility strings.
-5. Clean up logger/config dependencies before moving compression, prefix, or
+4. Clean up logger/config dependencies before moving compression, prefix, or
    error helpers.
-6. Defer port/orchestration work until the remaining pure/config boundaries are
+5. Defer port/orchestration work until the remaining pure/config boundaries are
    settled.
 
 ## PR 1 - Thin First Slice (#7546)
@@ -176,8 +181,15 @@ Source: `packages/sync-core/src/`. All exports come through `index.ts`.
 - `OperationLogEntry`, `EntityConflict`, `ConflictResult`, `EntityChange`,
   `MultiEntityPayload`.
 - `VectorClock = Record<string, number>`.
-- `FULL_STATE_OP_TYPES`, `isFullStateOpType`, `isMultiEntityPayload`,
-  `extractActionPayload`.
+- `isMultiEntityPayload`, `extractActionPayload`.
+
+**Full-state op-type helper factory** (`full-state-op-types.ts`):
+
+- `createFullStateOpTypeHelpers<TOpType>(fullStateOpTypes)` returns the
+  host-owned `FULL_STATE_OP_TYPES` set and `isFullStateOpType` predicate.
+- The package keeps deprecated SP compatibility exports for
+  `FULL_STATE_OP_TYPES` / `isFullStateOpType`, but reusable hosts should
+  instantiate their own helper instead of using those defaults.
 
 **LWW factory** (`lww-update-action-types.ts`):
 
@@ -202,7 +214,8 @@ Each previously-public symbol path keeps working via thin shims:
 
 - `src/app/op-log/core/operation.types.ts` re-exports generic symbols and
   redeclares SP-narrowed `Operation`, `OperationLogEntry`, `EntityChange`,
-  `EntityConflict`, `ConflictResult`, and `MultiEntityPayload`.
+  `EntityConflict`, `ConflictResult`, and `MultiEntityPayload`. It also
+  instantiates `createFullStateOpTypeHelpers()` with SP's full-state op strings.
 - `src/app/op-log/core/types/apply.types.ts` redeclares app-narrowed apply
   result/options types.
 - `src/app/op-log/core/lww-update-action-types.ts` instantiates the LWW helper
@@ -222,8 +235,8 @@ Each previously-public symbol path keeps working via thin shims:
 - Fix comments that imply `sync-core` depends on `shared-schema`. The build may
   run after `shared-schema`, but the package dependency direction must remain
   absent.
-- Decide whether `FULL_STATE_OP_TYPES` is acceptable compatibility debt for PR 1
-  or whether it should already become app-configurable.
+- Resolved in follow-up: `FULL_STATE_OP_TYPES` is now app-configured via
+  `createFullStateOpTypeHelpers()`.
 
 ### Verification
 
@@ -277,6 +290,8 @@ Already present:
 - `EncryptAndCompressHandlerService` now accepts a `SyncLogger` constructor
   argument and uses the app adapter by default, proving the direct-constructor
   path for package-level classes without changing sync behavior.
+- `op-log/encryption/compression-handler.ts` now routes compression failures
+  through `SyncLogger` + `toSyncLogError()` and logs only safe length metadata.
 - A deliberate bad-import check was run with a temporary
   `packages/sync-core/src/__boundary-check__.ts` importing `@angular/core`;
   `npm run lint:file -- packages/sync-core/src/__boundary-check__.ts` failed on
@@ -391,9 +406,9 @@ Initial candidate-file audit:
 
 - `op-log/encryption/encrypt-and-compress-handler.service.ts`: safe prefix and
   flag metadata now goes through `SyncLogger`.
-- `op-log/encryption/compression-handler.ts`: still logs raw errors directly;
-  before moving, route failures through `toSyncLogError()` and preserve only
-  safe counts such as compressed input length.
+- `op-log/encryption/compression-handler.ts`: routes failures through
+  `toSyncLogError()` and preserves only safe counts such as input length. It
+  remains app-side until compression errors are split from app diagnostics.
 - `op-log/core/errors/sync-errors.ts`: not move-ready. Several constructors log
   validation params, raw samples, or additional objects; split generic error
   classes from app-specific diagnostics before routing through `SyncLogger`.
diff --git a/packages/sync-core/src/apply.types.ts b/packages/sync-core/src/apply.types.ts
index 4c2b03ee93..8efbbe4024 100644
--- a/packages/sync-core/src/apply.types.ts
+++ b/packages/sync-core/src/apply.types.ts
@@ -1,4 +1,4 @@
-import { Operation } from './operation.types';
+import type { Operation } from './operation.types';
 
 /**
  * Result of applying a batch of operations.
@@ -6,16 +6,16 @@ import { Operation } from './operation.types';
  * Allows callers to handle partial success scenarios where some operations
  * were applied before an error occurred.
  */
-export interface ApplyOperationsResult {
+export interface ApplyOperationsResult<TOperation extends Operation<string> = Operation> {
   /** Operations that were successfully applied. */
-  appliedOps: Operation[];
+  appliedOps: TOperation[];
 
   /**
    * If an error occurred, this contains the failed operation and the error.
    * Operations after this one in the batch were NOT applied.
    */
   failedOp?: {
-    op: Operation;
+    op: TOperation;
     error: Error;
   };
 }
diff --git a/packages/sync-core/src/conflict-resolution.ts b/packages/sync-core/src/conflict-resolution.ts
index 18d0640439..6836335d81 100644
--- a/packages/sync-core/src/conflict-resolution.ts
+++ b/packages/sync-core/src/conflict-resolution.ts
@@ -24,7 +24,7 @@ export interface DeepEqualOptions {
 }
 
 export interface EntityFrontierContext {
-  localOpsForEntity: Pick<Operation, 'vectorClock'>[];
+  localOpsForEntity: Pick<Operation<string>, 'vectorClock'>[];
   appliedFrontier: VectorClock | undefined;
   snapshotVectorClock: VectorClock | undefined;
   snapshotEntityKeys: ReadonlySet<string> | undefined;
@@ -41,7 +41,7 @@ export interface ClockCorruptionAdjustmentOptions {
 }
 
 export interface LwwConflictResolutionPlan<
-  TConflict extends EntityConflict = EntityConflict,
+  TConflict extends EntityConflictLike<Operation<string>> = EntityConflict,
 > {
   conflict: TConflict;
   winner: LwwConflictResolutionWinner;
@@ -51,25 +51,29 @@ export interface LwwConflictResolutionPlan<
   remoteMaxTimestamp?: number;
 }
 
-export interface LwwConflictResolutionPlanningOptions {
-  isArchiveAction: (op: Operation) => boolean;
+export interface LwwConflictResolutionPlanningOptions<
+  TOperation extends Operation<string> = Operation,
+> {
+  isArchiveAction: (op: TOperation) => boolean;
   toEntityKey?: (entityType: string, entityId: string) => string;
 }
 
-export interface LocalDeleteRemoteUpdateConversionOptions {
+export interface LocalDeleteRemoteUpdateConversionOptions<
+  TOperation extends Operation<string> = Operation,
+> {
   payloadKey: string | ((entityType: string) => string);
   toLwwUpdateActionType: (entityType: string) => string;
   isSingletonEntityId?: (entityId: string) => boolean;
   onMissingBaseEntity?: (ctx: {
-    conflict: EntityConflict;
-    localDeleteOp: Operation | undefined;
-    remoteOp: Operation;
+    conflict: EntityConflictLike<TOperation>;
+    localDeleteOp: TOperation | undefined;
+    remoteOp: TOperation;
     localDeletePayloadKeys: string[] | undefined;
   }) => void;
 }
 
-export type EntityConflictLike<TOperation extends Operation> = Omit<
-  EntityConflict,
+export type EntityConflictLike<TOperation extends Operation<string>> = Omit<
+  EntityConflict<Operation<string>>,
   'localOps' | 'remoteOps'
 > & {
   localOps: TOperation[];
@@ -77,7 +81,7 @@ export type EntityConflictLike<TOperation extends Operation> = Omit<
 };
 
 export interface LwwResolvedConflict<
-  TOperation extends Operation = Operation,
+  TOperation extends Operation<string> = Operation,
   TConflict extends EntityConflictLike<TOperation> = EntityConflictLike<TOperation>,
 > {
   conflict: TConflict;
@@ -86,14 +90,16 @@ export interface LwwResolvedConflict<
 }
 
 export interface LwwResolutionPartitionOptions<
-  TOperation extends Operation,
+  TOperation extends Operation<string>,
   TConflict extends EntityConflictLike<TOperation> = EntityConflictLike<TOperation>,
 > {
   processRemoteWinnerOps?: (conflict: TConflict) => TOperation[];
   toEntityKey?: (entityType: string, entityId: string) => string;
 }
 
-export interface LwwResolutionPartitions<TOperation extends Operation = Operation> {
+export interface LwwResolutionPartitions<
+  TOperation extends Operation<string> = Operation,
+> {
   localWinsCount: number;
   remoteWinsCount: number;
   remoteWinsOps: TOperation[];
@@ -106,7 +112,7 @@ export interface LwwResolutionPartitions<TOperation extends Operation = Operatio
 
 const resolvePayloadKey = (
   entityType: string,
-  payloadKey: LocalDeleteRemoteUpdateConversionOptions['payloadKey'],
+  payloadKey: LocalDeleteRemoteUpdateConversionOptions<Operation<string>>['payloadKey'],
 ): string => (typeof payloadKey === 'function' ? payloadKey(entityType) : payloadKey);
 
 const getPayloadKeys = (payload: unknown): string[] | undefined => {
@@ -166,10 +172,10 @@ export const extractUpdateChanges = (
  * and singleton-id semantics so the core remains domain-agnostic.
  */
 export const convertLocalDeleteRemoteUpdatesToLww = <
-  TOperation extends Operation = Operation,
+  TOperation extends Operation<string> = Operation,
 >(
   conflict: EntityConflictLike<TOperation>,
-  options: LocalDeleteRemoteUpdateConversionOptions,
+  options: LocalDeleteRemoteUpdateConversionOptions<TOperation>,
 ): TOperation[] => {
   const localDeleteOp = conflict.localOps.find((op) => op.opType === OpType.Delete);
 
@@ -281,7 +287,7 @@ export const deepEqual = (
  * the same resulting state.
  */
 export const isIdenticalConflict = (
-  conflict: EntityConflict,
+  conflict: EntityConflict<Operation<string>>,
   logger: SyncLogger = NOOP_SYNC_LOGGER,
 ): boolean => {
   const { localOps, remoteOps } = conflict;
@@ -324,9 +330,9 @@ export const isIdenticalConflict = (
 /**
  * Suggests a conservative default conflict resolution for the UI/orchestrator.
  */
-export const suggestConflictResolution = (
-  localOps: Operation[],
-  remoteOps: Operation[],
+export const suggestConflictResolution = <TOperation extends Operation<string>>(
+  localOps: TOperation[],
+  remoteOps: TOperation[],
 ): ConflictResolutionSuggestion => {
   if (localOps.length === 0) return 'remote';
   if (remoteOps.length === 0) return 'local';
@@ -363,10 +369,11 @@ export const suggestConflictResolution = (
  * be created and which app-side factory should create it.
  */
 export const planLwwConflictResolutions = <
-  TConflict extends EntityConflict = EntityConflict,
+  TOperation extends Operation<string> = Operation,
+  TConflict extends EntityConflictLike<TOperation> = EntityConflictLike<TOperation>,
 >(
   conflicts: TConflict[],
-  options: LwwConflictResolutionPlanningOptions,
+  options: LwwConflictResolutionPlanningOptions<TOperation>,
 ): Array<LwwConflictResolutionPlan<TConflict>> => {
   const toEntityKey =
     options.toEntityKey ??
@@ -443,7 +450,7 @@ export const planLwwConflictResolutions = <
  * pending local ops are superseded.
  */
 export const partitionLwwResolutions = <
-  TOperation extends Operation = Operation,
+  TOperation extends Operation<string> = Operation,
   TConflict extends EntityConflictLike<TOperation> = EntityConflictLike<TOperation>,
   TResolution extends LwwResolvedConflict<TOperation, TConflict> = LwwResolvedConflict<
     TOperation,
diff --git a/packages/sync-core/src/full-state-op-types.ts b/packages/sync-core/src/full-state-op-types.ts
new file mode 100644
index 0000000000..74a664a898
--- /dev/null
+++ b/packages/sync-core/src/full-state-op-types.ts
@@ -0,0 +1,43 @@
+import { OpType } from './operation.types';
+
+export interface FullStateOpTypeHelpers<TOpType extends string = string> {
+  FULL_STATE_OP_TYPES: ReadonlySet<TOpType>;
+  isFullStateOpType: (opType: string) => opType is TOpType;
+}
+
+/**
+ * Creates host-owned helpers for classifying operations that replace full state.
+ *
+ * Full-state operation names are application wire conventions, so sync-core
+ * only provides the classification helper and the host supplies the op strings.
+ */
+export const createFullStateOpTypeHelpers = <TOpType extends string>(
+  fullStateOpTypes: readonly TOpType[],
+): FullStateOpTypeHelpers<TOpType> => {
+  const fullStateOpTypeSet: ReadonlySet<TOpType> = new Set(fullStateOpTypes);
+
+  return {
+    FULL_STATE_OP_TYPES: fullStateOpTypeSet,
+    isFullStateOpType: (opType: string): opType is TOpType =>
+      fullStateOpTypeSet.has(opType as TOpType),
+  };
+};
+
+const compatibilityFullStateOpTypeHelpers = createFullStateOpTypeHelpers<OpType>([
+  OpType.SyncImport,
+  OpType.BackupImport,
+  OpType.Repair,
+]);
+
+/**
+ * @deprecated Super Productivity compatibility export. Hosts should instantiate
+ * their own helper with `createFullStateOpTypeHelpers()`.
+ */
+export const FULL_STATE_OP_TYPES =
+  compatibilityFullStateOpTypeHelpers.FULL_STATE_OP_TYPES;
+
+/**
+ * @deprecated Super Productivity compatibility export. Hosts should instantiate
+ * their own helper with `createFullStateOpTypeHelpers()`.
+ */
+export const isFullStateOpType = compatibilityFullStateOpTypeHelpers.isFullStateOpType;
diff --git a/packages/sync-core/src/index.ts b/packages/sync-core/src/index.ts
index d121961f6f..f0253842c3 100644
--- a/packages/sync-core/src/index.ts
+++ b/packages/sync-core/src/index.ts
@@ -1,11 +1,5 @@
 // Operation log primitives — the generic, app-agnostic core of the sync engine.
-export {
-  OpType,
-  FULL_STATE_OP_TYPES,
-  isFullStateOpType,
-  isMultiEntityPayload,
-  extractActionPayload,
-} from './operation.types';
+export { OpType, isMultiEntityPayload, extractActionPayload } from './operation.types';
 export type {
   VectorClock,
   Operation,
@@ -35,6 +29,14 @@ export type {
   SyncImportFilterKeepReason,
 } from './sync-import-filter';
 
+// Full-state operation classification helper. Hosts supply their own op strings.
+export {
+  FULL_STATE_OP_TYPES,
+  createFullStateOpTypeHelpers,
+  isFullStateOpType,
+} from './full-state-op-types';
+export type { FullStateOpTypeHelpers } from './full-state-op-types';
+
 // LWW (Last-Writer-Wins) update action-type helpers — factory parameterized by
 // the host application's entity-type list, so the lib stays domain-agnostic.
 export { createLwwUpdateActionTypeHelpers } from './lww-update-action-types';
diff --git a/packages/sync-core/src/operation.types.ts b/packages/sync-core/src/operation.types.ts
index ea7b9b0c1a..43bdfe30c0 100644
--- a/packages/sync-core/src/operation.types.ts
+++ b/packages/sync-core/src/operation.types.ts
@@ -8,15 +8,24 @@ export enum OpType {
   Delete = 'DEL',
   Move = 'MOV', // For list reordering
   Batch = 'BATCH', // For bulk operations (import, mass update)
-  /** Replaces entire app state from remote sync. All concurrent ops are discarded. */
+  /**
+   * Host-defined full-state compatibility string used by Super Productivity.
+   * Reusable core logic must receive full-state classification from the host.
+   */
   SyncImport = 'SYNC_IMPORT',
-  /** Replaces entire app state from backup file. All concurrent ops are discarded. */
+  /**
+   * Host-defined full-state compatibility string used by Super Productivity.
+   * Reusable core logic must receive full-state classification from the host.
+   */
   BackupImport = 'BACKUP_IMPORT',
-  /** Auto-repair operation containing full repaired state. */
+  /**
+   * Host-defined full-state compatibility string used by Super Productivity.
+   * Reusable core logic must receive full-state classification from the host.
+   */
   Repair = 'REPAIR',
 }
 
-export interface Operation {
+export interface Operation<TOpType extends string = OpType> {
   /**
    * Unique identifier for the operation.
    * Should be a UUID v7 (time-ordered) to allow for rough chronological sorting
@@ -36,7 +45,7 @@ export interface Operation {
    * High-level operation category (Create, Update, Delete, etc.).
    * Used for broad logic handling like persistence strategies or conflict resolution rules.
    */
-  opType: OpType;
+  opType: TOpType;
 
   // SCOPE
   /**
@@ -92,7 +101,7 @@ export interface Operation {
   schemaVersion: number;
 }
 
-export interface OperationLogEntry {
+export interface OperationLogEntry<TOperation extends Operation<string> = Operation> {
   /**
    * Local, monotonic auto-increment integer (IndexedDB primary key).
    * Strictly orders operations as they arrived or were generated on THIS specific device.
@@ -102,7 +111,7 @@ export interface OperationLogEntry {
   /**
    * The operation data itself (the synchronized part).
    */
-  op: Operation;
+  op: TOperation;
 
   /**
    * Local timestamp (epoch ms) indicating when this operation was written to the LOCAL database.
@@ -141,39 +150,20 @@ export interface OperationLogEntry {
   retryCount?: number;
 }
 
-export interface EntityConflict {
+export interface EntityConflict<TOperation extends Operation<string> = Operation> {
   entityType: string;
   entityId: string;
-  localOps: Operation[];
-  remoteOps: Operation[];
+  localOps: TOperation[];
+  remoteOps: TOperation[];
   suggestedResolution: 'local' | 'remote' | 'merge' | 'manual';
   mergedPayload?: unknown;
 }
 
-export interface ConflictResult {
-  nonConflicting: Operation[];
-  conflicts: EntityConflict[];
+export interface ConflictResult<TOperation extends Operation<string> = Operation> {
+  nonConflicting: TOperation[];
+  conflicts: EntityConflict<TOperation>[];
 }
 
-// =============================================================================
-// FULL-STATE OPERATION HELPERS
-// =============================================================================
-
-/**
- * OpTypes that contain full application state in their payload.
- */
-export const FULL_STATE_OP_TYPES = new Set<OpType>([
-  OpType.SyncImport,
-  OpType.BackupImport,
-  OpType.Repair,
-]);
-
-/**
- * Type guard to check if an operation is a full-state operation.
- */
-export const isFullStateOpType = (opType: OpType | string): boolean =>
-  FULL_STATE_OP_TYPES.has(opType as OpType);
-
 // =============================================================================
 // MULTI-ENTITY OPERATIONS
 // =============================================================================
@@ -181,10 +171,10 @@ export const isFullStateOpType = (opType: OpType | string): boolean =>
 /**
  * Represents a single entity change within a multi-entity operation.
  */
-export interface EntityChange {
+export interface EntityChange<TOpType extends string = OpType> {
   entityType: string;
   entityId: string;
-  opType: OpType;
+  opType: TOpType;
   /**
    * The actual changes:
    * - For Create: Full entity object
@@ -198,9 +188,9 @@ export interface EntityChange {
  * Payload wrapper for multi-entity operations.
  * Contains the original action payload plus all entity changes computed from state diff.
  */
-export interface MultiEntityPayload {
+export interface MultiEntityPayload<TOpType extends string = OpType> {
   actionPayload: Record<string, unknown>;
-  entityChanges: EntityChange[];
+  entityChanges: EntityChange<TOpType>[];
 }
 
 /**
diff --git a/packages/sync-core/tests/full-state-op-types.spec.ts b/packages/sync-core/tests/full-state-op-types.spec.ts
new file mode 100644
index 0000000000..9d869642ac
--- /dev/null
+++ b/packages/sync-core/tests/full-state-op-types.spec.ts
@@ -0,0 +1,104 @@
+import { describe, expect, it } from 'vitest';
+import {
+  FULL_STATE_OP_TYPES,
+  createFullStateOpTypeHelpers,
+  isFullStateOpType,
+} from '../src/full-state-op-types';
+import {
+  partitionLwwResolutions,
+  planLwwConflictResolutions,
+} from '../src/conflict-resolution';
+import { OpType } from '../src/operation.types';
+import type {
+  ConflictResult,
+  EntityConflict,
+  MultiEntityPayload,
+  Operation,
+  OperationLogEntry,
+} from '../src/operation.types';
+
+describe('createFullStateOpTypeHelpers', () => {
+  it('classifies only the host-supplied op types as full-state operations', () => {
+    const helpers = createFullStateOpTypeHelpers([
+      'SYNC_IMPORT',
+      'BACKUP_IMPORT',
+      'REPAIR',
+    ] as const);
+
+    expect(helpers.FULL_STATE_OP_TYPES.has('SYNC_IMPORT')).toBe(true);
+    expect(helpers.FULL_STATE_OP_TYPES.has('BACKUP_IMPORT')).toBe(true);
+    expect(helpers.FULL_STATE_OP_TYPES.has('REPAIR')).toBe(true);
+    expect(helpers.isFullStateOpType('SYNC_IMPORT')).toBe(true);
+    expect(helpers.isFullStateOpType('CRT')).toBe(false);
+  });
+
+  it('does not hard-code Super Productivity full-state op names', () => {
+    const helpers = createFullStateOpTypeHelpers(['HOST_FULL_REPLACE'] as const);
+
+    expect(helpers.FULL_STATE_OP_TYPES.has('HOST_FULL_REPLACE')).toBe(true);
+    expect(helpers.isFullStateOpType('HOST_FULL_REPLACE')).toBe(true);
+    expect(helpers.isFullStateOpType('SYNC_IMPORT')).toBe(false);
+  });
+
+  it('keeps deprecated Super Productivity compatibility exports', () => {
+    expect(FULL_STATE_OP_TYPES.has(OpType.SyncImport)).toBe(true);
+    expect(FULL_STATE_OP_TYPES.has(OpType.BackupImport)).toBe(true);
+    expect(FULL_STATE_OP_TYPES.has(OpType.Repair)).toBe(true);
+    expect(isFullStateOpType(OpType.SyncImport)).toBe(true);
+    expect(isFullStateOpType(OpType.Create)).toBe(false);
+  });
+
+  it('allows host-specific operation opType strings across exported wrappers', () => {
+    type HostOpType = OpType | 'HOST_FULL_REPLACE';
+    type HostOperation = Operation<HostOpType>;
+
+    const hostOp: HostOperation = {
+      id: 'op-1',
+      actionType: '[Host] Replace State',
+      opType: 'HOST_FULL_REPLACE',
+      entityType: 'HOST_ENTITY',
+      payload: {},
+      clientId: 'client-1',
+      vectorClock: { client1: 1 },
+      timestamp: 1,
+      schemaVersion: 1,
+    };
+    const entry: OperationLogEntry<HostOperation> = {
+      seq: 1,
+      op: hostOp,
+      appliedAt: 1,
+      source: 'local',
+    };
+    const conflict: EntityConflict<HostOperation> = {
+      entityType: 'HOST_ENTITY',
+      entityId: 'entity-1',
+      localOps: [hostOp],
+      remoteOps: [hostOp],
+      suggestedResolution: 'manual',
+    };
+    const result: ConflictResult<HostOperation> = {
+      nonConflicting: [hostOp],
+      conflicts: [conflict],
+    };
+    const multiEntityPayload: MultiEntityPayload<HostOpType> = {
+      actionPayload: {},
+      entityChanges: [
+        {
+          entityType: 'HOST_ENTITY',
+          entityId: 'entity-1',
+          opType: 'HOST_FULL_REPLACE',
+          changes: {},
+        },
+      ],
+    };
+    const plans = planLwwConflictResolutions<HostOperation>([conflict], {
+      isArchiveAction: (op: HostOperation): boolean => op.actionType === '[Host] Archive',
+    });
+    const partitions = partitionLwwResolutions<HostOperation>(plans);
+
+    expect(entry.op.opType).toBe('HOST_FULL_REPLACE');
+    expect(result.conflicts[0].localOps[0].opType).toBe('HOST_FULL_REPLACE');
+    expect(multiEntityPayload.entityChanges[0].opType).toBe('HOST_FULL_REPLACE');
+    expect(partitions.remoteWinsOps[0].opType).toBe('HOST_FULL_REPLACE');
+  });
+});
diff --git a/src/app/op-log/core/operation.types.ts b/src/app/op-log/core/operation.types.ts
index bbb84ad0d7..f6384ef052 100644
--- a/src/app/op-log/core/operation.types.ts
+++ b/src/app/op-log/core/operation.types.ts
@@ -14,18 +14,26 @@ import type {
 } from '@sp/sync-core';
 import type { EntityType as SharedEntityType } from '@sp/shared-schema';
 import { ENTITY_TYPES } from '@sp/shared-schema';
+import {
+  createFullStateOpTypeHelpers,
+  isMultiEntityPayload as libIsMultiEntityPayload,
+  OpType,
+} from '@sp/sync-core';
 import { ActionType } from './action-types.enum';
 
-export {
-  OpType,
-  FULL_STATE_OP_TYPES,
-  isFullStateOpType,
-  extractActionPayload,
-} from '@sp/sync-core';
-import { isMultiEntityPayload as libIsMultiEntityPayload } from '@sp/sync-core';
+export { OpType, extractActionPayload } from '@sp/sync-core';
 export type { VectorClock };
 export { ENTITY_TYPES, ActionType };
 
+const fullStateOpTypeHelpers = createFullStateOpTypeHelpers<OpType>([
+  OpType.SyncImport,
+  OpType.BackupImport,
+  OpType.Repair,
+]);
+
+export const FULL_STATE_OP_TYPES = fullStateOpTypeHelpers.FULL_STATE_OP_TYPES;
+export const isFullStateOpType = fullStateOpTypeHelpers.isFullStateOpType;
+
 /**
  * Entity type — Super Productivity's domain set, sourced from `@sp/shared-schema`
  * so client and server agree on the union.
diff --git a/src/app/op-log/encryption/compression-handler.spec.ts b/src/app/op-log/encryption/compression-handler.spec.ts
index be580ab994..87556fb7e7 100644
--- a/src/app/op-log/encryption/compression-handler.spec.ts
+++ b/src/app/op-log/encryption/compression-handler.spec.ts
@@ -1,3 +1,4 @@
+import { NOOP_SYNC_LOGGER } from '@sp/sync-core';
 import { OpLog } from '../../core/log';
 import { DecompressError } from '../core/errors/sync-errors';
 import {
@@ -9,6 +10,7 @@ import {
 describe('compression-handler', () => {
   beforeEach(() => {
     spyOn(OpLog, 'err').and.stub();
+    spyOn(OpLog, 'log').and.stub();
     spyOn(console, 'log').and.stub();
   });
 
@@ -46,6 +48,45 @@ describe('compression-handler', () => {
       );
     });
 
+    it('logs only sanitized error metadata on decompression failure', async () => {
+      (OpLog.err as jasmine.Spy).calls.reset();
+      const invalidGzip = btoa('not gzip data');
+
+      await expectAsync(decompressGzipFromString(invalidGzip)).toBeRejectedWithError(
+        DecompressError,
+      );
+
+      expect(OpLog.err).toHaveBeenCalledOnceWith(
+        '[compression-handler] gzip decompression failed',
+        jasmine.objectContaining({ name: jasmine.any(String) }),
+        {
+          inputLength: invalidGzip.length,
+          sanitizedInputLength: invalidGzip.length,
+        },
+      );
+      expect((OpLog.err as jasmine.Spy).calls.mostRecent().args[1] instanceof Error)
+        .withContext('logged error identity must be sanitized')
+        .toBeFalse();
+      const additionalLogText = (OpLog.log as jasmine.Spy).calls
+        .allArgs()
+        .flat()
+        .join('\n');
+      expect(additionalLogText).not.toContain('not gzip data');
+    });
+
+    it('preserves DecompressError when the injected logger throws', async () => {
+      const throwingLogger = {
+        ...NOOP_SYNC_LOGGER,
+        err: () => {
+          throw new Error('logger failed');
+        },
+      };
+
+      await expectAsync(
+        decompressGzipFromString(btoa('not gzip data'), throwingLogger),
+      ).toBeRejectedWithError(DecompressError);
+    });
+
     // Issue #6581: decompressGzipFromString should sanitize base64 input
     // to handle data corruption from WebDAV servers, partial uploads, etc.
 
diff --git a/src/app/op-log/encryption/compression-handler.ts b/src/app/op-log/encryption/compression-handler.ts
index cccc5ddc24..e4b06b18c9 100644
--- a/src/app/op-log/encryption/compression-handler.ts
+++ b/src/app/op-log/encryption/compression-handler.ts
@@ -1,5 +1,11 @@
-import { CompressError, DecompressError } from '../core/errors/sync-errors';
-import { OpLog } from '../../core/log';
+import type { SyncLogMeta, SyncLogger } from '@sp/sync-core';
+import { toSyncLogError } from '@sp/sync-core';
+import {
+  CompressError,
+  DecompressError,
+  extractErrorMessage,
+} from '../core/errors/sync-errors';
+import { OP_LOG_SYNC_LOGGER } from '../core/sync-logger.adapter';
 
 /**
  * Reads all bytes from a ReadableStream without using the Response constructor,
@@ -29,12 +35,43 @@ const readAllBytes = async (
   return result;
 };
 
+const logCompressionError = (
+  logger: SyncLogger,
+  message: string,
+  error: unknown,
+  meta: SyncLogMeta,
+): void => {
+  try {
+    logger.err(message, toSyncLogError(error), meta);
+  } catch {
+    // Logging is best-effort and must not mask the original compression error.
+  }
+};
+
+const toSafeErrorForWrapper = (error: unknown): Error => {
+  const syncLogError = toSyncLogError(error);
+  const safeError = new Error(extractErrorMessage(error) ?? syncLogError.name);
+  safeError.name = syncLogError.name;
+
+  if (syncLogError.code !== undefined) {
+    Object.defineProperty(safeError, 'code', {
+      value: syncLogError.code,
+      enumerable: false,
+    });
+  }
+
+  return safeError;
+};
+
 /**
  * Compresses a string using gzip and returns the raw bytes.
  * Use this for binary transmission (e.g., HTTP with Content-Encoding: gzip).
  */
 // eslint-disable-next-line prefer-arrow/prefer-arrow-functions
-export async function compressWithGzip(input: string): Promise<Uint8Array> {
+export async function compressWithGzip(
+  input: string,
+  logger: SyncLogger = OP_LOG_SYNC_LOGGER,
+): Promise<Uint8Array> {
   try {
     const stream = new CompressionStream('gzip');
     const writer = stream.writable.getWriter();
@@ -47,8 +84,10 @@ export async function compressWithGzip(input: string): Promise<Uint8Array> {
     const [, compressed] = await Promise.all([writePromise, readPromise]);
     return compressed;
   } catch (error) {
-    OpLog.err(error);
-    throw new CompressError(error);
+    logCompressionError(logger, '[compression-handler] gzip compression failed', error, {
+      inputLength: input.length,
+    });
+    throw new CompressError(toSafeErrorForWrapper(error));
   }
 }
 
@@ -57,7 +96,10 @@ export async function compressWithGzip(input: string): Promise<Uint8Array> {
  * Use this for JSON payloads where binary data needs string encoding.
  */
 // eslint-disable-next-line prefer-arrow/prefer-arrow-functions
-export async function compressWithGzipToString(input: string): Promise<string> {
+export async function compressWithGzipToString(
+  input: string,
+  logger: SyncLogger = OP_LOG_SYNC_LOGGER,
+): Promise<string> {
   try {
     const stream = new CompressionStream('gzip');
     const writer = stream.writable.getWriter();
@@ -79,8 +121,15 @@ export async function compressWithGzipToString(input: string): Promise<string> {
       reader.readAsDataURL(new Blob([compressed as unknown as BlobPart]));
     });
   } catch (error) {
-    OpLog.err(error);
-    throw new CompressError(error);
+    logCompressionError(
+      logger,
+      '[compression-handler] gzip string compression failed',
+      error,
+      {
+        inputLength: input.length,
+      },
+    );
+    throw new CompressError(toSafeErrorForWrapper(error));
   }
 }
 
@@ -108,6 +157,7 @@ const sanitizeBase64 = (input: string): string => {
 // eslint-disable-next-line prefer-arrow/prefer-arrow-functions
 export async function decompressGzipFromString(
   compressedBase64: string,
+  logger: SyncLogger = OP_LOG_SYNC_LOGGER,
 ): Promise<string> {
   try {
     const sanitized = sanitizeBase64(compressedBase64);
@@ -128,10 +178,15 @@ export async function decompressGzipFromString(
     const decoded = new TextDecoder().decode(decompressed);
     return decoded;
   } catch (error) {
-    OpLog.err(error);
-    if (compressedBase64) {
-      OpLog.err('base64 input length:', compressedBase64.length);
-    }
-    throw new DecompressError(error);
+    logCompressionError(
+      logger,
+      '[compression-handler] gzip decompression failed',
+      error,
+      {
+        inputLength: compressedBase64.length,
+        sanitizedInputLength: sanitizeBase64(compressedBase64).length,
+      },
+    );
+    throw new DecompressError(toSafeErrorForWrapper(error));
   }
 }
diff --git a/src/app/op-log/encryption/encrypt-and-compress-handler.service.ts b/src/app/op-log/encryption/encrypt-and-compress-handler.service.ts
index 5ae8f8368b..b4397f686f 100644
--- a/src/app/op-log/encryption/encrypt-and-compress-handler.service.ts
+++ b/src/app/op-log/encryption/encrypt-and-compress-handler.service.ts
@@ -86,7 +86,7 @@ export class EncryptAndCompressHandlerService {
     );
     let dataStr = JSON.stringify(data);
     if (isCompress) {
-      dataStr = await compressWithGzipToString(dataStr);
+      dataStr = await compressWithGzipToString(dataStr, this._logger);
     }
     if (isEncrypt) {
       if (!encryptKey || encryptKey.length === 0) {
@@ -152,7 +152,7 @@ export class EncryptAndCompressHandlerService {
     }
 
     if (isCompressed) {
-      outStr = await decompressGzipFromString(outStr);
+      outStr = await decompressGzipFromString(outStr, this._logger);
     }
 
     let parsedData: T;