diff --git a/internal/translator/antigravity/gemini/antigravity_gemini_request.go b/internal/translator/antigravity/gemini/antigravity_gemini_request.go
index 6664fb34e..1952a60a2 100644
--- a/internal/translator/antigravity/gemini/antigravity_gemini_request.go
+++ b/internal/translator/antigravity/gemini/antigravity_gemini_request.go
@@ -639,6 +639,74 @@ type FunctionCallGroup struct {
 	CallNames       []string // ordered function call names for backfilling empty response names
 }
 
+func normalizeAntigravityInlineDataPart(part gjson.Result) ([]byte, bool) {
+	inline := part.Get("inlineData")
+	if !inline.Exists() {
+		inline = part.Get("inline_data")
+	}
+	if !inline.Exists() {
+		return nil, false
+	}
+	data := inline.Get("data").String()
+	if data == "" {
+		return nil, false
+	}
+	mimeType := inline.Get("mimeType").String()
+	if mimeType == "" {
+		mimeType = inline.Get("mime_type").String()
+	}
+	if mimeType == "" {
+		// Cloud Code Assist ignores inlineData without mimeType.
+		mimeType = "image/png"
+	}
+	out := []byte(`{"inlineData":{"mimeType":"","data":""}}`)
+	out, _ = sjson.SetBytes(out, "inlineData.mimeType", mimeType)
+	out, _ = sjson.SetBytes(out, "inlineData.data", data)
+	return out, true
+}
+
+func attachInlineDataToFunctionResponse(response gjson.Result, images [][]byte) gjson.Result {
+	if len(images) == 0 {
+		return response
+	}
+	target := []byte(response.Raw)
+	for _, img := range images {
+		target, _ = sjson.SetRawBytes(target, "functionResponse.parts.-1", img)
+	}
+	return gjson.ParseBytes(target)
+}
+
+// collectFunctionResponsesWithSiblingInlineData keeps functionResponse parts and
+// moves sibling inline_data/inlineData onto the nearest preceding functionResponse.
+// Leading images before the first functionResponse attach to that first response.
+func collectFunctionResponsesWithSiblingInlineData(parts gjson.Result) []gjson.Result {
+	responses := make([]gjson.Result, 0)
+	leadingImages := make([][]byte, 0)
+	current := -1
+	parts.ForEach(func(_, part gjson.Result) bool {
+		if part.Get("functionResponse").Exists() {
+			responses = append(responses, part)
+			current = len(responses) - 1
+			if len(leadingImages) > 0 {
+				responses[current] = attachInlineDataToFunctionResponse(responses[current], leadingImages)
+				leadingImages = nil
+			}
+			return true
+		}
+		imagePart, ok := normalizeAntigravityInlineDataPart(part)
+		if !ok {
+			return true
+		}
+		if current >= 0 {
+			responses[current] = attachInlineDataToFunctionResponse(responses[current], [][]byte{imagePart})
+			return true
+		}
+		leadingImages = append(leadingImages, imagePart)
+		return true
+	})
+	return responses
+}
+
 // parseFunctionResponseRaw attempts to normalize a function response part into a JSON object string.
 // Falls back to a minimal "functionResponse" object when parsing fails.
 // fallbackName is used when the response's own name is empty.
@@ -749,14 +817,8 @@ func fixCLIToolResponse(input []byte) ([]byte, error) {
 		role := value.Get("role").String()
 		parts := value.Get("parts")
 
-		// Check if this content has function responses
-		var responsePartsInThisContent []gjson.Result
-		parts.ForEach(func(_, part gjson.Result) bool {
-			if part.Get("functionResponse").Exists() {
-				responsePartsInThisContent = append(responsePartsInThisContent, part)
-			}
-			return true
-		})
+		// Collect function responses and attach sibling inlineData to the nearest one.
+		responsePartsInThisContent := collectFunctionResponsesWithSiblingInlineData(parts)
 
 		// If this content has function responses, collect them
 		if len(responsePartsInThisContent) > 0 {
diff --git a/internal/translator/antigravity/gemini/antigravity_gemini_request_test.go b/internal/translator/antigravity/gemini/antigravity_gemini_request_test.go
index 56f8332ae..227087acd 100644
--- a/internal/translator/antigravity/gemini/antigravity_gemini_request_test.go
+++ b/internal/translator/antigravity/gemini/antigravity_gemini_request_test.go
@@ -954,3 +954,190 @@ func TestSanitizeAntigravityClaudeGeminiRequestSignatures_LargeNumberDoesNotHalt
 		t.Fatalf("expected hidden thoughtSignature to be stripped despite large number, got %s", fcSig.Raw)
 	}
 }
+
+func TestFixCLIToolResponse_AttachesSiblingInlineDataToNearestFunctionResponse(t *testing.T) {
+	tests := []struct {
+		name  string
+		parts string
+		want  []struct {
+			id   string
+			mime string
+			data string
+		}
+	}{
+		{
+			name: "snake_case sibling after single response",
+			parts: `{"functionResponse":{"name":"read","response":{"result":"Read image file [image/png]"},"id":"call_1"}},` +
+				`{"inline_data":{"mime_type":"image/png","data":"QUJD"}}`,
+			want: []struct {
+				id   string
+				mime string
+				data string
+			}{{id: "call_1", mime: "image/png", data: "QUJD"}},
+		},
+		{
+			name: "camelCase sibling after single response",
+			parts: `{"functionResponse":{"name":"read","response":{"result":"ok"},"id":"call_1"}},` +
+				`{"inlineData":{"mimeType":"image/webp","data":"NEW"}}`,
+			want: []struct {
+				id   string
+				mime string
+				data string
+			}{{id: "call_1", mime: "image/webp", data: "NEW"}},
+		},
+		{
+			name: "append sibling onto existing functionResponse.parts",
+			parts: `{"functionResponse":{"name":"read","response":{"result":"ok"},"id":"call_1","parts":[{"inlineData":{"mimeType":"image/gif","data":"OLD"}}]}},` +
+				`{"inlineData":{"mimeType":"image/webp","data":"NEW"}}`,
+			want: []struct {
+				id   string
+				mime string
+				data string
+			}{
+				{id: "call_1", mime: "image/gif", data: "OLD"},
+			},
+		},
+		{
+			name: "interleaved siblings attach to nearest response",
+			parts: `{"functionResponse":{"name":"read","response":{"result":"A"},"id":"call_a"}},` +
+				`{"inline_data":{"mime_type":"image/png","data":"AAA"}},` +
+				`{"functionResponse":{"name":"read","response":{"result":"B"},"id":"call_b"}},` +
+				`{"inline_data":{"mime_type":"image/jpeg","data":"BBB"}}`,
+			want: []struct {
+				id   string
+				mime string
+				data string
+			}{
+				{id: "call_a", mime: "image/png", data: "AAA"},
+				{id: "call_b", mime: "image/jpeg", data: "BBB"},
+			},
+		},
+		{
+			name: "leading sibling attaches to first response",
+			parts: `{"inline_data":{"mime_type":"image/png","data":"LEAD"}},` +
+				`{"functionResponse":{"name":"read","response":{"result":"A"},"id":"call_a"}},` +
+				`{"functionResponse":{"name":"read","response":{"result":"B"},"id":"call_b"}}`,
+			want: []struct {
+				id   string
+				mime string
+				data string
+			}{
+				{id: "call_a", mime: "image/png", data: "LEAD"},
+			},
+		},
+		{
+			name: "missing mimeType defaults to image/png",
+			parts: `{"functionResponse":{"name":"read","response":{"result":"ok"},"id":"call_1"}},` +
+				`{"inlineData":{"data":"QUJD"}}`,
+			want: []struct {
+				id   string
+				mime string
+				data string
+			}{{id: "call_1", mime: "image/png", data: "QUJD"}},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			modelParts := `{"functionCall":{"name":"read","id":"call_1"}}`
+			if tt.name == "interleaved siblings attach to nearest response" || tt.name == "leading sibling attaches to first response" {
+				modelParts = `{"functionCall":{"name":"read","id":"call_a"}},{"functionCall":{"name":"read","id":"call_b"}}`
+			}
+			input := `{"request":{"contents":[` +
+				`{"role":"model","parts":[` + modelParts + `]},` +
+				`{"role":"user","parts":[` + tt.parts + `]}` +
+				`]}}`
+			result, err := fixCLIToolResponse([]byte(input))
+			if err != nil {
+				t.Fatalf("fixCLIToolResponse failed: %v", err)
+			}
+			contents := gjson.GetBytes(result, "request.contents").Array()
+			if len(contents) != 2 {
+				t.Fatalf("contents = %d, want 2. Output: %s", len(contents), result)
+			}
+			funcParts := contents[1].Get("parts").Array()
+			gotByID := map[string][]gjson.Result{}
+			for _, part := range funcParts {
+				fr := part.Get("functionResponse")
+				gotByID[fr.Get("id").String()] = fr.Get("parts").Array()
+			}
+			for _, want := range tt.want {
+				images := gotByID[want.id]
+				found := false
+				for _, img := range images {
+					if img.Get("inlineData.data").String() == want.data && img.Get("inlineData.mimeType").String() == want.mime {
+						found = true
+						break
+					}
+				}
+				if !found {
+					t.Fatalf("id=%s missing inlineData mime=%s data=%s. Output: %s", want.id, want.mime, want.data, result)
+				}
+			}
+			if tt.name == "interleaved siblings attach to nearest response" {
+				if len(gotByID["call_a"]) != 1 || len(gotByID["call_b"]) != 1 {
+					t.Fatalf("nearest attribution failed: A=%d B=%d. Output: %s", len(gotByID["call_a"]), len(gotByID["call_b"]), result)
+				}
+			}
+			if tt.name == "leading sibling attaches to first response" {
+				if len(gotByID["call_b"]) != 0 {
+					t.Fatalf("leading image leaked onto call_b. Output: %s", result)
+				}
+			}
+			if tt.name == "append sibling onto existing functionResponse.parts" {
+				images := gotByID["call_1"]
+				if len(images) != 2 {
+					t.Fatalf("existing+sibling parts = %d, want 2. Output: %s", len(images), result)
+				}
+				if images[1].Get("inlineData.data").String() != "NEW" {
+					t.Fatalf("appended sibling data = %q, want NEW. Output: %s", images[1].Get("inlineData.data").String(), result)
+				}
+			}
+		})
+	}
+}
+
+func TestConvertGeminiRequestToAntigravity_PreservesSiblingToolImageOnUserRole(t *testing.T) {
+	input := []byte(`{
+		"contents": [
+			{"role":"user","parts":[{"text":"read file"}]},
+			{"role":"model","parts":[{"functionCall":{"name":"read","args":{},"id":"call_1"}}]},
+			{"role":"user","parts":[
+				{"functionResponse":{"name":"read","response":{"result":"Read image file [image/png]"},"id":"call_1"}},
+				{"inline_data":{"mime_type":"image/png","data":"QUJD"}}
+			]}
+		]
+	}`)
+	out := ConvertGeminiRequestToAntigravity("gemini-3-flash", input, false)
+	contents := gjson.GetBytes(out, "request.contents").Array()
+	if len(contents) != 3 {
+		t.Fatalf("contents = %d, want 3. Output: %s", len(contents), out)
+	}
+	funcContent := contents[2]
+	if got := funcContent.Get("role").String(); got != "user" {
+		t.Fatalf("role = %q, want user after Antigravity normalization. Output: %s", got, out)
+	}
+	funcResp := funcContent.Get("parts.0.functionResponse")
+	if !funcResp.Exists() {
+		t.Fatalf("functionResponse missing. Output: %s", out)
+	}
+	if got := funcResp.Get("id").String(); got != "call_1" {
+		t.Fatalf("id = %q, want call_1", got)
+	}
+	if got := funcResp.Get("response.result").String(); got != "Read image file [image/png]" {
+		t.Fatalf("result = %q", got)
+	}
+	inlineData := funcResp.Get("parts.0.inlineData")
+	if !inlineData.Exists() {
+		t.Fatalf("functionResponse.parts.0.inlineData missing. Output: %s", out)
+	}
+	if got := inlineData.Get("mimeType").String(); got != "image/png" {
+		t.Fatalf("mimeType = %q, want image/png", got)
+	}
+	if got := inlineData.Get("data").String(); got != "QUJD" {
+		t.Fatalf("data = %q, want QUJD", got)
+	}
+	if funcContent.Get("parts.1.inline_data").Exists() || funcContent.Get("parts.1.inlineData").Exists() {
+		t.Fatalf("sibling inline data should be absorbed into functionResponse.parts. Output: %s", out)
+	}
+}
diff --git a/internal/translator/antigravity/openai/responses/antigravity_openai-responses_request_test.go b/internal/translator/antigravity/openai/responses/antigravity_openai-responses_request_test.go
index 7dfad0eb7..f283ceba9 100644
--- a/internal/translator/antigravity/openai/responses/antigravity_openai-responses_request_test.go
+++ b/internal/translator/antigravity/openai/responses/antigravity_openai-responses_request_test.go
@@ -265,3 +265,93 @@ func TestConvertOpenAIResponsesRequestToAntigravity_GeminiReasoningUsesNativeTho
 		t.Fatalf("parts[0].thoughtSignature = %q, want preserved Gemini signature. Output: %s", got, out)
 	}
 }
+
+func TestConvertOpenAIResponsesRequestToAntigravity_PreservesToolResultImage(t *testing.T) {
+	inputJSON := `{
+		"model": "gemini-3-flash",
+		"input": [
+			{"role": "user", "content": [{"type": "input_text", "text": "请帮我读取分析这张图片"}]},
+			{"type": "function_call", "id": "fc_read", "call_id": "call_read_1", "name": "read", "arguments": "{\"path\":\"/path/to/image.png\"}"},
+			{
+				"type": "function_call_output",
+				"call_id": "call_read_1",
+				"output": [
+					{"type": "input_text", "text": "Read image file [image/png]"},
+					{"type": "input_image", "detail": "auto", "image_url": "data:image/png;base64,QUJD"}
+				]
+			}
+		]
+	}`
+	out := ConvertOpenAIResponsesRequestToAntigravity("gemini-3-flash", []byte(inputJSON), false)
+	contents := gjson.GetBytes(out, "request.contents").Array()
+	if len(contents) != 3 {
+		t.Fatalf("expected 3 contents, got %d. Output: %s", len(contents), out)
+	}
+	funcContent := contents[2]
+	if got := funcContent.Get("role").String(); got != "user" {
+		t.Fatalf("role = %q, want user. Output: %s", got, out)
+	}
+	funcResp := funcContent.Get("parts.0.functionResponse")
+	if !funcResp.Exists() {
+		t.Fatalf("functionResponse should exist. Output: %s", out)
+	}
+	if got := funcResp.Get("id").String(); got != "call_read_1" {
+		t.Fatalf("id = %q, want call_read_1", got)
+	}
+	if got := funcResp.Get("name").String(); got != "read" {
+		t.Fatalf("name = %q, want read", got)
+	}
+	inlineData := funcResp.Get("parts.0.inlineData")
+	if !inlineData.Exists() {
+		t.Fatalf("expected functionResponse.parts.0.inlineData to exist, got: %s", out)
+	}
+	if got := inlineData.Get("mimeType").String(); got != "image/png" {
+		t.Errorf("expected mimeType image/png, got %q", got)
+	}
+	if got := inlineData.Get("data").String(); got != "QUJD" {
+		t.Errorf("expected data QUJD, got %q", got)
+	}
+}
+
+func TestConvertOpenAIResponsesRequestToAntigravity_AttachesParallelToolImagesToNearestResponse(t *testing.T) {
+	inputJSON := `{
+		"model": "gemini-3-flash",
+		"input": [
+			{"role": "user", "content": [{"type": "input_text", "text": "read both"}]},
+			{"type": "function_call", "id": "fc_a", "call_id": "call_a", "name": "read", "arguments": "{\"path\":\"/tmp/a.png\"}"},
+			{"type": "function_call", "id": "fc_b", "call_id": "call_b", "name": "read", "arguments": "{\"path\":\"/tmp/b.png\"}"},
+			{
+				"type": "function_call_output",
+				"call_id": "call_a",
+				"output": [
+					{"type": "input_text", "text": "file A"},
+					{"type": "input_image", "image_url": "data:image/png;base64,AAA"}
+				]
+			},
+			{
+				"type": "function_call_output",
+				"call_id": "call_b",
+				"output": [
+					{"type": "input_text", "text": "file B"},
+					{"type": "input_image", "image_url": "data:image/jpeg;base64,BBB"}
+				]
+			}
+		]
+	}`
+	out := ConvertOpenAIResponsesRequestToAntigravity("gemini-3-flash", []byte(inputJSON), false)
+	parts := gjson.GetBytes(out, "request.contents.2.parts").Array()
+	if len(parts) != 2 {
+		t.Fatalf("function parts = %d, want 2. Output: %s", len(parts), out)
+	}
+	got := map[string]string{}
+	for _, part := range parts {
+		fr := part.Get("functionResponse")
+		got[fr.Get("id").String()] = fr.Get("parts.0.inlineData.data").String()
+	}
+	if got["call_a"] != "AAA" {
+		t.Fatalf("call_a image = %q, want AAA. Output: %s", got["call_a"], out)
+	}
+	if got["call_b"] != "BBB" {
+		t.Fatalf("call_b image = %q, want BBB. Output: %s", got["call_b"], out)
+	}
+}