fix(relay): stop injecting empty tools into Claude requests

relaykit/relayconvert/claude_default_max_tokens_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/QuantumNous/new-api/relaykit/dto"
 	"github.com/QuantumNous/new-api/relaykit/relayconvert/convmeta"
 	sharedclaude "github.com/QuantumNous/new-api/relaykit/relayconvert/internal/shared/claude"
+	kitutil "github.com/QuantumNous/new-api/relaykit/relayconvert/kitutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -104,6 +105,82 @@ func TestClaudeThinkingAdapterSatisfiesMaxTokensWithoutCallback(t *testing.T) {
 	assert.Equal(t, uint(1280), *got.MaxTokens)
 }
 
+func TestOpenAIChatRequestToClaudeMessagesOmitsEmptyTools(t *testing.T) {
+	maxTokens := uint(16)
+	tests := []struct {
+		name      string
+		request   dto.GeneralOpenAIRequest
+		wantTools bool
+	}{
+		{
+			name: "omitted tools",
+			request: dto.GeneralOpenAIRequest{
+				Model:     "claude-test",
+				MaxTokens: &maxTokens,
+				Messages:  []dto.Message{{Role: "user", Content: "hi"}},
+			},
+		},
+		{
+			name: "explicit empty tools",
+			request: dto.GeneralOpenAIRequest{
+				Model:     "claude-test",
+				MaxTokens: &maxTokens,
+				Messages:  []dto.Message{{Role: "user", Content: "hi"}},
+				Tools:     []dto.ToolCallRequest{},
+			},
+		},
+		{
+			name: "function tool",
+			request: dto.GeneralOpenAIRequest{
+				Model:     "claude-test",
+				MaxTokens: &maxTokens,
+				Messages:  []dto.Message{{Role: "user", Content: "hi"}},
+				Tools: []dto.ToolCallRequest{{
+					Type: "function",
+					Function: dto.FunctionRequest{
+						Name:        "get_weather",
+						Description: "Get weather by city",
+						Parameters: map[string]any{
+							"type":       "object",
+							"properties": map[string]any{"city": map[string]any{"type": "string"}},
+							"required":   []any{"city"},
+						},
+					},
+				}},
+			},
+			wantTools: true,
+		},
+		{
+			name: "web search only",
+			request: dto.GeneralOpenAIRequest{
+				Model:            "claude-test",
+				MaxTokens:        &maxTokens,
+				Messages:         []dto.Message{{Role: "user", Content: "hi"}},
+				WebSearchOptions: &dto.WebSearchOptions{SearchContextSize: "low"},
+			},
+			wantTools: true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, err := OpenAIChatRequestToClaudeMessages(context.Background(), &convmeta.Values{}, test.request)
+			require.NoError(t, err)
+
+			body, err := kitutil.Marshal(got)
+			require.NoError(t, err)
+
+			if test.wantTools {
+				assert.NotNil(t, got.Tools)
+				assert.Contains(t, string(body), `"tools":`)
+				return
+			}
+			assert.Nil(t, got.Tools)
+			assert.NotContains(t, string(body), `"tools":`)
+		})
+	}
+}
+
 func claudeDefaultsMeta(defaultMaxTokens func(string) int) convmeta.Meta {
 	return &convmeta.Values{Options: &convmeta.Options{
 		Claude: convmeta.ClaudeOptions{DefaultMaxTokens: defaultMaxTokens},

relaykit/relayconvert/internal/oai_chat/to_claude_messages_req.go

@@ -101,7 +101,9 @@ func OpenAIChatRequestToClaudeMessages(c context.Context, info convmeta.Meta, te
 		Model:         textRequest.Model,
 		StopSequences: nil,
 		Temperature:   textRequest.Temperature,
-		Tools:         claudeTools,
+	}
+	if len(claudeTools) > 0 {
+		claudeRequest.Tools = claudeTools
 	}
 	if maxTokens := textRequest.GetMaxTokens(); maxTokens > 0 {
 		claudeRequest.MaxTokens = kitutil.GetPointer(maxTokens)