diff --git a/src/database.ts b/src/database.ts
index f3c62671..f7f20cf3 100644
--- a/src/database.ts
+++ b/src/database.ts
@@ -1685,6 +1685,45 @@ export class WorklogDatabase {
     this.triggerAutoSync();
   }
 
+  /**
+   * Upsert work items non-destructively (INSERT OR REPLACE without clearing).
+   *
+   * Unlike `import()`, this method does NOT call `clearWorkItems()` or
+   * `clearDependencyEdges()`. It saves each provided item via the store's
+   * `saveWorkItem()` (which uses INSERT … ON CONFLICT DO UPDATE) so that
+   * existing items not in the provided array are preserved.
+   *
+   * When `dependencyEdges` is provided, only edges whose `fromId` or `toId`
+   * belongs to the provided items are upserted; all other edges are untouched.
+   *
+   * If `items` is empty the method is a no-op (no export/sync triggered).
+   */
+  upsertItems(items: WorkItem[], dependencyEdges?: DependencyEdge[]): void {
+    if (items.length === 0) {
+      return;
+    }
+
+    for (const item of items) {
+      this.store.saveWorkItem(item);
+    }
+
+    if (dependencyEdges) {
+      const affectedIds = new Set(items.map(i => i.id));
+      for (const edge of dependencyEdges) {
+        if (
+          (affectedIds.has(edge.fromId) || affectedIds.has(edge.toId)) &&
+          this.store.getWorkItem(edge.fromId) &&
+          this.store.getWorkItem(edge.toId)
+        ) {
+          this.store.saveDependencyEdge(edge);
+        }
+      }
+    }
+
+    this.exportToJsonl();
+    this.triggerAutoSync();
+  }
+
   /**
    * Add a dependency edge (fromId depends on toId)
    */
diff --git a/tests/unit/database-upsert.test.ts b/tests/unit/database-upsert.test.ts
new file mode 100644
index 00000000..b6d9e8b1
--- /dev/null
+++ b/tests/unit/database-upsert.test.ts
@@ -0,0 +1,291 @@
+/**
+ * Tests for WorklogDatabase.upsertItems()
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import * as fs from 'fs';
+import { WorklogDatabase } from '../../src/database.js';
+import { createTempDir, cleanupTempDir, createTempJsonlPath, createTempDbPath } from '../test-utils.js';
+
+describe('WorklogDatabase.upsertItems', () => {
+  let tempDir: string;
+  let dbPath: string;
+  let jsonlPath: string;
+  let db: WorklogDatabase;
+
+  beforeEach(() => {
+    tempDir = createTempDir();
+    dbPath = createTempDbPath(tempDir);
+    jsonlPath = createTempJsonlPath(tempDir);
+    db = new WorklogDatabase('TEST', dbPath, jsonlPath, true, true);
+  });
+
+  afterEach(() => {
+    db.close();
+    cleanupTempDir(tempDir);
+  });
+
+  it('should upsert a single item without deleting existing items', () => {
+    // Arrange: create two existing items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+
+    // Act: upsert a new item C
+    const itemC = {
+      ...db.create({ title: 'Item C - placeholder' }),
+      title: 'Item C - upserted',
+    };
+    // Delete the placeholder before upserting
+    db.delete(itemC.id);
+    db.upsertItems([{ ...itemC }]);
+
+    // Assert: all three items exist
+    const all = db.getAll();
+    expect(all.length).toBe(3);
+    expect(all.find(i => i.id === itemA.id)).toBeDefined();
+    expect(all.find(i => i.id === itemB.id)).toBeDefined();
+    const upserted = all.find(i => i.id === itemC.id);
+    expect(upserted).toBeDefined();
+    expect(upserted!.title).toBe('Item C - upserted');
+  });
+
+  it('should update an existing item in place via upsert', () => {
+    // Arrange: create an item
+    const item = db.create({ title: 'Original title' });
+
+    // Act: upsert the same item with a new title
+    db.upsertItems([{ ...item, title: 'Updated title', updatedAt: new Date().toISOString() }]);
+
+    // Assert: the item is updated, not duplicated
+    const all = db.getAll();
+    expect(all.length).toBe(1);
+    expect(all[0].title).toBe('Updated title');
+  });
+
+  it('should not delete any items when upserting an empty array', () => {
+    // Arrange: create items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+
+    // Act: upsert empty array
+    db.upsertItems([]);
+
+    // Assert: both items still exist
+    const all = db.getAll();
+    expect(all.length).toBe(2);
+    expect(all.find(i => i.id === itemA.id)).toBeDefined();
+    expect(all.find(i => i.id === itemB.id)).toBeDefined();
+  });
+
+  it('should not trigger export/sync when upserting an empty array', () => {
+    // Arrange: create an item so JSONL has content, then record mtime
+    db.create({ title: 'Existing item' });
+    const statBefore = fs.statSync(jsonlPath);
+    const mtimeBefore = statBefore.mtimeMs;
+
+    // Small delay to ensure mtime difference is detectable
+    const until = Date.now() + 50;
+    while (Date.now() < until) { /* wait */ }
+
+    // Act: upsert empty array
+    db.upsertItems([]);
+
+    // Assert: JSONL file was not re-written
+    const statAfter = fs.statSync(jsonlPath);
+    expect(statAfter.mtimeMs).toBe(mtimeBefore);
+  });
+
+  it('should preserve existing items when upserting a subset', () => {
+    // Arrange: create three items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+    const itemC = db.create({ title: 'Item C' });
+
+    // Act: upsert only itemA with an update
+    db.upsertItems([{ ...itemA, title: 'Item A - updated' }]);
+
+    // Assert: all three items exist, only A is updated
+    const all = db.getAll();
+    expect(all.length).toBe(3);
+    expect(all.find(i => i.id === itemA.id)!.title).toBe('Item A - updated');
+    expect(all.find(i => i.id === itemB.id)!.title).toBe('Item B');
+    expect(all.find(i => i.id === itemC.id)!.title).toBe('Item C');
+  });
+
+  it('should upsert dependency edges only for affected items', () => {
+    // Arrange: create items and an existing edge
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+    const itemC = db.create({ title: 'Item C' });
+    db.addDependencyEdge(itemA.id, itemB.id); // A depends on B
+
+    // Act: upsert itemC with a new edge (C depends on A)
+    db.upsertItems(
+      [{ ...itemC, title: 'Item C - updated' }],
+      [
+        { fromId: itemC.id, toId: itemA.id, createdAt: new Date().toISOString() },
+      ],
+    );
+
+    // Assert: original edge (A->B) is preserved, new edge (C->A) added
+    const edgesFromA = db.listDependencyEdgesFrom(itemA.id);
+    expect(edgesFromA.length).toBe(1);
+    expect(edgesFromA[0].toId).toBe(itemB.id);
+
+    const edgesFromC = db.listDependencyEdgesFrom(itemC.id);
+    expect(edgesFromC.length).toBe(1);
+    expect(edgesFromC[0].toId).toBe(itemA.id);
+  });
+
+  it('should ignore dependency edges where both endpoints are outside affected items', () => {
+    // Arrange: create items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+    const itemC = db.create({ title: 'Item C' });
+
+    // Act: upsert itemC but pass an edge between A and B (neither is in the upsert set)
+    db.upsertItems(
+      [{ ...itemC, title: 'Item C - updated' }],
+      [
+        { fromId: itemA.id, toId: itemB.id, createdAt: new Date().toISOString() },
+      ],
+    );
+
+    // Assert: the A->B edge was NOT created because neither A nor B is in the affected set
+    const edgesFromA = db.listDependencyEdgesFrom(itemA.id);
+    expect(edgesFromA.length).toBe(0);
+  });
+
+  it('should upsert edges where one endpoint is in the affected set', () => {
+    // Arrange: create items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+
+    // Act: upsert itemA with an edge (A depends on B) — A is in the affected set
+    db.upsertItems(
+      [{ ...itemA, title: 'Item A - updated' }],
+      [
+        { fromId: itemA.id, toId: itemB.id, createdAt: new Date().toISOString() },
+      ],
+    );
+
+    // Assert: edge was created
+    const edgesFromA = db.listDependencyEdgesFrom(itemA.id);
+    expect(edgesFromA.length).toBe(1);
+    expect(edgesFromA[0].toId).toBe(itemB.id);
+  });
+
+  it('should skip edges where referenced items do not exist in the database', () => {
+    // Arrange: create one item
+    const itemA = db.create({ title: 'Item A' });
+
+    // Act: upsert itemA with an edge referencing a non-existent item
+    db.upsertItems(
+      [{ ...itemA }],
+      [
+        { fromId: itemA.id, toId: 'TEST-NONEXISTENT', createdAt: new Date().toISOString() },
+      ],
+    );
+
+    // Assert: no edge created
+    const edgesFromA = db.listDependencyEdgesFrom(itemA.id);
+    expect(edgesFromA.length).toBe(0);
+  });
+
+  it('should not clear existing dependency edges when upserting', () => {
+    // Arrange: create items with existing edges
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+    const itemC = db.create({ title: 'Item C' });
+    db.addDependencyEdge(itemA.id, itemB.id); // A depends on B
+    db.addDependencyEdge(itemB.id, itemC.id); // B depends on C
+
+    // Act: upsert a totally new item with no edges
+    const itemD = {
+      ...db.create({ title: 'Item D - placeholder' }),
+      title: 'Item D - upserted',
+    };
+    db.delete(itemD.id);
+    db.upsertItems([{ ...itemD }]);
+
+    // Assert: all original edges are preserved
+    const edgesFromA = db.listDependencyEdgesFrom(itemA.id);
+    expect(edgesFromA.length).toBe(1);
+    expect(edgesFromA[0].toId).toBe(itemB.id);
+
+    const edgesFromB = db.listDependencyEdgesFrom(itemB.id);
+    expect(edgesFromB.length).toBe(1);
+    expect(edgesFromB[0].toId).toBe(itemC.id);
+  });
+
+  it('should export to JSONL after upserting non-empty items', () => {
+    // Arrange: create an item so JSONL exists
+    db.create({ title: 'Existing item' });
+    const statBefore = fs.statSync(jsonlPath);
+    const mtimeBefore = statBefore.mtimeMs;
+
+    // Small delay to ensure mtime difference is detectable
+    const until = Date.now() + 50;
+    while (Date.now() < until) { /* wait */ }
+
+    // Act: upsert a new item
+    const item = db.create({ title: 'Placeholder' });
+    db.delete(item.id);
+
+    // Wait again after delete export
+    const until2 = Date.now() + 50;
+    while (Date.now() < until2) { /* wait */ }
+    const statAfterDelete = fs.statSync(jsonlPath);
+    const mtimeAfterDelete = statAfterDelete.mtimeMs;
+
+    // Wait to detect next mtime change
+    const until3 = Date.now() + 50;
+    while (Date.now() < until3) { /* wait */ }
+
+    db.upsertItems([{ ...item, title: 'Upserted' }]);
+
+    // Assert: JSONL file was re-written
+    const statAfter = fs.statSync(jsonlPath);
+    expect(statAfter.mtimeMs).toBeGreaterThan(mtimeAfterDelete);
+  });
+
+  it('should handle upserting multiple items at once', () => {
+    // Arrange: create existing items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+
+    // Act: upsert both with updates plus a new item
+    const itemC = {
+      ...db.create({ title: 'Item C - placeholder' }),
+      title: 'Item C - new',
+    };
+    db.delete(itemC.id);
+
+    db.upsertItems([
+      { ...itemA, title: 'Item A - batch updated' },
+      { ...itemB, title: 'Item B - batch updated' },
+      { ...itemC },
+    ]);
+
+    // Assert: all three items exist with correct titles
+    const all = db.getAll();
+    expect(all.length).toBe(3);
+    expect(all.find(i => i.id === itemA.id)!.title).toBe('Item A - batch updated');
+    expect(all.find(i => i.id === itemB.id)!.title).toBe('Item B - batch updated');
+    expect(all.find(i => i.id === itemC.id)!.title).toBe('Item C - new');
+  });
+
+  it('should not modify the existing import() method behavior', () => {
+    // Arrange: create items
+    const itemA = db.create({ title: 'Item A' });
+    const itemB = db.create({ title: 'Item B' });
+
+    // Act: use import() with only one item (the destructive path)
+    db.import([{ ...itemA, title: 'Item A - imported' }]);
+
+    // Assert: import() still clears all items first (only itemA exists)
+    const all = db.getAll();
+    expect(all.length).toBe(1);
+    expect(all[0].title).toBe('Item A - imported');
+  });
+});