diff --git a/packages/core/src/ai-model/models/deepseek/adapter.ts b/packages/core/src/ai-model/models/deepseek/adapter.ts
index 371ac39837..5ea83a383f 100644
--- a/packages/core/src/ai-model/models/deepseek/adapter.ts
+++ b/packages/core/src/ai-model/models/deepseek/adapter.ts
@@ -30,14 +30,18 @@ function parseDeepSeekCoordinateValues(
   expectedLength: number,
   label: string,
 ): number[] {
-  const coordinateTexts = String(input).match(/\d+/g);
-  if (coordinateTexts?.length !== expectedLength) {
+  const coordinateTexts = String(input).match(/[+-]?\d+/g);
+  const coordinates = coordinateTexts?.map(Number);
+  if (
+    coordinates?.length !== expectedLength ||
+    !coordinates.every((coordinate) => coordinate >= 0)
+  ) {
     throw new Error(
       `DeepSeek ${label} locate result must contain exactly ${expectedLength} positive integers, got ${coordinateTexts?.length ?? 0}`,
     );
   }
 
-  return coordinateTexts.map(Number);
+  return coordinates;
 }
 
 function parseDeepSeekPointLocateValue(input: unknown): LocateResultValue {
diff --git a/packages/core/tests/unit-test/model-adapter/deepseek.test.ts b/packages/core/tests/unit-test/model-adapter/deepseek.test.ts
index 235565a3ee..42183454c1 100644
--- a/packages/core/tests/unit-test/model-adapter/deepseek.test.ts
+++ b/packages/core/tests/unit-test/model-adapter/deepseek.test.ts
@@ -209,6 +209,8 @@ describe('deepseek model adapter', () => {
   it.each([
     '<｜｜point｜｜>[[928.5,780]]<｜｜/point｜｜>',
     '<｜｜point｜｜>no coordinates<｜｜/point｜｜>',
+    '<｜｜point｜｜>[-10,500]<｜｜/point｜｜>',
+    '<｜｜point｜｜>[500,-10]<｜｜/point｜｜>',
   ])('rejects output without exactly two integers: %s', (content) => {
     const locateAdapter = getStandardLocateAdapter().element;
     const rawResult = locateAdapter.protocol.parseRawResponse(
@@ -226,6 +228,28 @@ describe('deepseek model adapter', () => {
     ).toThrow('must contain exactly 2 positive integers');
   });
 
+  it.each([
+    '<｜｜ref｜｜>target<｜｜/ref｜｜><｜｜box｜｜>[[-1,100,200,300]]<｜｜/box｜｜>',
+    '<｜｜ref｜｜>target<｜｜/ref｜｜><｜｜box｜｜>[[100,-1,200,300]]<｜｜/box｜｜>',
+    '<｜｜ref｜｜>target<｜｜/ref｜｜><｜｜box｜｜>[[100,200,-1,300]]<｜｜/box｜｜>',
+    '<｜｜ref｜｜>target<｜｜/ref｜｜><｜｜box｜｜>[[100,200,300,-1]]<｜｜/box｜｜>',
+  ])('rejects negative bbox coordinates: %s', (content) => {
+    const locateAdapter = getStandardLocateAdapter().searchArea!;
+    const rawResult = locateAdapter.protocol.parseRawResponse(
+      content,
+      locateAdapter.resultCodec.promptSpec,
+    );
+    if (rawResult.kind !== 'located') {
+      throw new Error('DeepSeek response should contain a raw location');
+    }
+
+    expect(() =>
+      locateAdapter.resultCodec.toPixelBbox(rawResult.target, {
+        preparedSize: { width: 1000, height: 1000 },
+      }),
+    ).toThrow('must contain exactly 4 positive integers');
+  });
+
   it.each([
     '<｜｜point｜｜>[928,780]<｜｜/point｜｜>',
     '<｜｜point｜｜>[[928 780]]<｜｜/point｜｜>',