refactor: move tool call parsing and formatting logic to a dedicated internal/toolcall package

internal/adapter/claude/handler_utils.go

@@ -1,12 +1,12 @@
 package claude
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"fmt"
 	"strings"
 
 	"ds2api/internal/prompt"
-	"ds2api/internal/util"
 )
 
 func normalizeClaudeMessages(messages []any) []any {
@@ -98,7 +98,7 @@ func buildClaudeToolPrompt(tools []any) string {
 	}
 	return "You have access to these tools:\n\n" +
 		strings.Join(toolSchemas, "\n\n") + "\n\n" +
-		util.BuildToolCallInstructions(names)
+		toolcall.BuildToolCallInstructions(names)
 }
 
 func formatClaudeToolResultForPrompt(block map[string]any) string {

internal/adapter/claude/stream_runtime_finalize.go

@@ -1,6 +1,7 @@
 package claude
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"fmt"
 	"time"
@@ -46,9 +47,9 @@ func (s *claudeStreamRuntime) finalize(stopReason string) {
 	finalText := cleanVisibleOutput(s.text.String(), s.stripReferenceMarkers)
 
 	if s.bufferToolContent {
-		detected := util.ParseStandaloneToolCalls(finalText, s.toolNames)
+		detected := toolcall.ParseStandaloneToolCalls(finalText, s.toolNames)
 		if len(detected) == 0 && finalText == "" && finalThinking != "" {
-			detected = util.ParseStandaloneToolCalls(finalThinking, s.toolNames)
+			detected = toolcall.ParseStandaloneToolCalls(finalThinking, s.toolNames)
 		}
 		if len(detected) > 0 {
 			stopReason = "tool_use"

internal/adapter/gemini/handler_generate.go

@@ -1,6 +1,7 @@
 package gemini
 
 import (
+	"ds2api/internal/toolcall"
 	"bytes"
 	"encoding/json"
 	"io"
@@ -186,9 +187,9 @@ func buildGeminiUsage(finalPrompt, finalThinking, finalText string, outputTokens
 }
 
 func buildGeminiPartsFromFinal(finalText, finalThinking string, toolNames []string) []map[string]any {
-	detected := util.ParseToolCalls(finalText, toolNames)
+	detected := toolcall.ParseToolCalls(finalText, toolNames)
 	if len(detected) == 0 && finalThinking != "" {
-		detected = util.ParseToolCalls(finalThinking, toolNames)
+		detected = toolcall.ParseToolCalls(finalThinking, toolNames)
 	}
 	if len(detected) > 0 {
 		parts := make([]map[string]any, 0, len(detected))

internal/adapter/openai/chat_stream_runtime.go

@@ -1,6 +1,7 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"net/http"
 	"strings"
@@ -8,7 +9,6 @@ import (
 	openaifmt "ds2api/internal/format/openai"
 	"ds2api/internal/sse"
 	streamengine "ds2api/internal/stream"
-	"ds2api/internal/util"
 )
 
 type chatStreamRuntime struct {
@@ -102,7 +102,7 @@ func (s *chatStreamRuntime) sendDone() {
 func (s *chatStreamRuntime) finalize(finishReason string) {
 	finalThinking := s.thinking.String()
 	finalText := cleanVisibleOutput(s.text.String(), s.stripReferenceMarkers)
-	detected := util.ParseStandaloneToolCallsDetailed(finalText, s.toolNames)
+	detected := toolcall.ParseStandaloneToolCallsDetailed(finalText, s.toolNames)
 	if len(detected.Calls) > 0 && !s.toolCallsDoneEmitted {
 		finishReason = "tool_calls"
 		delta := map[string]any{

internal/adapter/openai/handler_toolcall_format.go

@@ -1,6 +1,7 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -75,7 +76,7 @@ func injectToolPrompt(messages []map[string]any, tools []any, policy util.ToolCh
 
 // buildToolCallInstructions delegates to the shared util implementation.
 func buildToolCallInstructions(toolNames []string) string {
-	return util.BuildToolCallInstructions(toolNames)
+	return toolcall.BuildToolCallInstructions(toolNames)
 }
 
 func formatIncrementalStreamToolCallDeltas(deltas []toolCallDelta, ids map[int]string) []map[string]any {
@@ -138,7 +139,7 @@ func filterIncrementalToolCallDeltasByAllowed(deltas []toolCallDelta, allowedNam
 	return out
 }
 
-func formatFinalStreamToolCallsWithStableIDs(calls []util.ParsedToolCall, ids map[int]string) []map[string]any {
+func formatFinalStreamToolCallsWithStableIDs(calls []toolcall.ParsedToolCall, ids map[int]string) []map[string]any {
 	if len(calls) == 0 {
 		return nil
 	}

internal/adapter/openai/responses_handler.go

@@ -1,6 +1,7 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"io"
 	"net/http"
@@ -119,7 +120,7 @@ func (h *Handler) handleResponsesNonStream(w http.ResponseWriter, resp *http.Res
 	if writeUpstreamEmptyOutputError(w, sanitizedThinking, sanitizedText, result.ContentFilter) {
 		return
 	}
-	textParsed := util.ParseStandaloneToolCallsDetailed(sanitizedText, toolNames)
+	textParsed := toolcall.ParseStandaloneToolCallsDetailed(sanitizedText, toolNames)
 	logResponsesToolPolicyRejection(traceID, toolChoice, textParsed, "text")
 
 	callCount := len(textParsed.Calls)
@@ -200,7 +201,7 @@ func (h *Handler) handleResponsesStream(w http.ResponseWriter, r *http.Request,
 	})
 }
 
-func logResponsesToolPolicyRejection(traceID string, policy util.ToolChoicePolicy, parsed util.ToolCallParseResult, channel string) {
+func logResponsesToolPolicyRejection(traceID string, policy util.ToolChoicePolicy, parsed toolcall.ToolCallParseResult, channel string) {
 	rejected := filteredRejectedToolNamesForLog(parsed.RejectedToolNames)
 	if !parsed.RejectedByPolicy || len(rejected) == 0 {
 		return

internal/adapter/openai/responses_stream_runtime_core.go

@@ -1,6 +1,7 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"net/http"
 	"strings"
 
@@ -107,7 +108,7 @@ func (s *responsesStreamRuntime) finalize() {
 		s.processToolStreamEvents(flushToolSieve(&s.sieve, s.toolNames), true)
 	}
 
-	textParsed := util.ParseStandaloneToolCallsDetailed(finalText, s.toolNames)
+	textParsed := toolcall.ParseStandaloneToolCallsDetailed(finalText, s.toolNames)
 	detected := textParsed.Calls
 	s.logToolPolicyRejections(textParsed)
 
@@ -163,8 +164,8 @@ func (s *responsesStreamRuntime) finalize() {
 	s.sendDone()
 }
 
-func (s *responsesStreamRuntime) logToolPolicyRejections(textParsed util.ToolCallParseResult) {
-	logRejected := func(parsed util.ToolCallParseResult, channel string) {
+func (s *responsesStreamRuntime) logToolPolicyRejections(textParsed toolcall.ToolCallParseResult) {
+	logRejected := func(parsed toolcall.ToolCallParseResult, channel string) {
 		rejected := filteredRejectedToolNamesForLog(parsed.RejectedToolNames)
 		if !parsed.RejectedByPolicy || len(rejected) == 0 {
 			return

internal/adapter/openai/responses_stream_runtime_toolcalls.go

@@ -1,11 +1,11 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"strings"
 
 	openaifmt "ds2api/internal/format/openai"
-	"ds2api/internal/util"
 
 	"github.com/google/uuid"
 )
@@ -208,7 +208,7 @@ func (s *responsesStreamRuntime) emitFunctionCallDeltaEvents(deltas []toolCallDe
 	}
 }
 
-func (s *responsesStreamRuntime) emitFunctionCallDoneEvents(calls []util.ParsedToolCall) {
+func (s *responsesStreamRuntime) emitFunctionCallDoneEvents(calls []toolcall.ParsedToolCall) {
 	for idx, tc := range calls {
 		if strings.TrimSpace(tc.Name) == "" {
 			continue

internal/adapter/openai/responses_stream_runtime_toolcalls_finalize.go

@@ -1,12 +1,12 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"sort"
 	"strings"
 
 	openaifmt "ds2api/internal/format/openai"
-	"ds2api/internal/util"
 )
 
 func (s *responsesStreamRuntime) closeIncompleteFunctionItems() {
@@ -57,7 +57,7 @@ func (s *responsesStreamRuntime) closeIncompleteFunctionItems() {
 	}
 }
 
-func (s *responsesStreamRuntime) buildCompletedResponseObject(finalThinking, finalText string, calls []util.ParsedToolCall) map[string]any {
+func (s *responsesStreamRuntime) buildCompletedResponseObject(finalThinking, finalText string, calls []toolcall.ParsedToolCall) map[string]any {
 	type indexedItem struct {
 		index int
 		item  map[string]any

internal/adapter/openai/tool_sieve_core.go

@@ -3,7 +3,7 @@ package openai
 import (
 	"strings"
 
-	"ds2api/internal/util"
+	"ds2api/internal/toolcall"
 )
 
 func processToolSieveChunk(state *toolStreamSieveState, chunk string, toolNames []string) []toolStreamEvent {
@@ -226,7 +226,7 @@ func findToolSegmentStart(s string) int {
 	return start
 }
 
-func consumeToolCapture(state *toolStreamSieveState, toolNames []string) (prefix string, calls []util.ParsedToolCall, suffix string, ready bool) {
+func consumeToolCapture(state *toolStreamSieveState, toolNames []string) (prefix string, calls []toolcall.ParsedToolCall, suffix string, ready bool) {
 	captured := state.capture.String()
 	if captured == "" {
 		return "", nil, "", false
@@ -267,7 +267,7 @@ func consumeToolCapture(state *toolStreamSieveState, toolNames []string) (prefix
 	}
 	prefixPart := captured[:start]
 	suffixPart := captured[end:]
-	parsed := util.ParseStandaloneToolCallsDetailed(obj, toolNames)
+	parsed := toolcall.ParseStandaloneToolCallsDetailed(obj, toolNames)
 	if len(parsed.Calls) == 0 {
 		if parsed.SawToolCallSyntax && parsed.RejectedByPolicy {
 			// Parsed as tool-call payload but rejected by schema/policy:

internal/adapter/openai/tool_sieve_state.go

@@ -1,9 +1,9 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"strings"
 
-	"ds2api/internal/util"
 )
 
 type toolStreamSieveState struct {
@@ -12,7 +12,7 @@ type toolStreamSieveState struct {
 	capturing        bool
 	recentTextTail   string
 	pendingToolRaw   string
-	pendingToolCalls []util.ParsedToolCall
+	pendingToolCalls []toolcall.ParsedToolCall
 	disableDeltas    bool
 	toolNameSent     bool
 	toolName         string
@@ -24,7 +24,7 @@ type toolStreamSieveState struct {
 
 type toolStreamEvent struct {
 	Content        string
-	ToolCalls      []util.ParsedToolCall
+	ToolCalls      []toolcall.ParsedToolCall
 	ToolCallDeltas []toolCallDelta
 }
 

internal/adapter/openai/tool_sieve_xml.go

@@ -1,10 +1,10 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"regexp"
 	"strings"
 
-	"ds2api/internal/util"
 )
 
 // --- XML tool call support for the streaming sieve ---
@@ -43,7 +43,7 @@ var xmlToolTagsToDetect = []string{"<tool_calls>", "<tool_calls\n", "<tool_call>
 	"<attempt_completion>", "<ask_followup_question>", "<new_task>"}
 
 // consumeXMLToolCapture tries to extract complete XML tool call blocks from captured text.
-func consumeXMLToolCapture(captured string, toolNames []string) (prefix string, calls []util.ParsedToolCall, suffix string, ready bool) {
+func consumeXMLToolCapture(captured string, toolNames []string) (prefix string, calls []toolcall.ParsedToolCall, suffix string, ready bool) {
 	lower := strings.ToLower(captured)
 	// Find the FIRST matching open/close pair, preferring wrapper tags.
 	// Tag pairs are ordered longest-first (e.g. <tool_calls before <tool_call)
@@ -66,7 +66,7 @@ func consumeXMLToolCapture(captured string, toolNames []string) (prefix string,
 		xmlBlock := captured[openIdx:closeEnd]
 		prefixPart := captured[:openIdx]
 		suffixPart := captured[closeEnd:]
-		parsed := util.ParseToolCalls(xmlBlock, toolNames)
+		parsed := toolcall.ParseToolCalls(xmlBlock, toolNames)
 		if len(parsed) > 0 {
 			prefixPart, suffixPart = trimWrappingJSONFence(prefixPart, suffixPart)
 			return prefixPart, parsed, suffixPart, true

internal/compat/go_compat_test.go

@@ -1,6 +1,7 @@
 package compat
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"os"
 	"path/filepath"
@@ -86,22 +87,22 @@ func TestGoCompatToolcallFixtures(t *testing.T) {
 		mustLoadJSON(t, fixturePath, &fixture)
 
 		var expected struct {
-			Calls             []util.ParsedToolCall `json:"calls"`
+			Calls             []toolcall.ParsedToolCall `json:"calls"`
 			SawToolCallSyntax bool                  `json:"sawToolCallSyntax"`
 			RejectedByPolicy  bool                  `json:"rejectedByPolicy"`
 			RejectedToolNames []string              `json:"rejectedToolNames"`
 		}
 		mustLoadJSON(t, expectedPath, &expected)
 
-		var got util.ToolCallParseResult
+		var got toolcall.ToolCallParseResult
 		switch strings.ToLower(strings.TrimSpace(fixture.Mode)) {
 		case "standalone":
-			got = util.ParseStandaloneToolCallsDetailed(fixture.Text, fixture.ToolNames)
+			got = toolcall.ParseStandaloneToolCallsDetailed(fixture.Text, fixture.ToolNames)
 		default:
-			got = util.ParseToolCallsDetailed(fixture.Text, fixture.ToolNames)
+			got = toolcall.ParseToolCallsDetailed(fixture.Text, fixture.ToolNames)
 		}
 		if got.Calls == nil {
-			got.Calls = []util.ParsedToolCall{}
+			got.Calls = []toolcall.ParsedToolCall{}
 		}
 		if got.RejectedToolNames == nil {
 			got.RejectedToolNames = []string{}

internal/format/claude/render.go

@@ -1,6 +1,7 @@
 package claude
 
 import (
+	"ds2api/internal/toolcall"
 	"fmt"
 	"time"
 
@@ -8,9 +9,9 @@ import (
 )
 
 func BuildMessageResponse(messageID, model string, normalizedMessages []any, finalThinking, finalText string, toolNames []string) map[string]any {
-	detected := util.ParseToolCalls(finalText, toolNames)
+	detected := toolcall.ParseToolCalls(finalText, toolNames)
 	if len(detected) == 0 && finalText == "" && finalThinking != "" {
-		detected = util.ParseToolCalls(finalThinking, toolNames)
+		detected = toolcall.ParseToolCalls(finalThinking, toolNames)
 	}
 	content := make([]map[string]any, 0, 4)
 	if finalThinking != "" {

internal/format/openai/render_chat.go

@@ -1,14 +1,14 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"strings"
 	"time"
 
-	"ds2api/internal/util"
 )
 
 func BuildChatCompletion(completionID, model, finalPrompt, finalThinking, finalText string, toolNames []string) map[string]any {
-	detected := util.ParseStandaloneToolCallsDetailed(finalText, toolNames)
+	detected := toolcall.ParseStandaloneToolCallsDetailed(finalText, toolNames)
 	finishReason := "stop"
 	messageObj := map[string]any{"role": "assistant", "content": finalText}
 	if strings.TrimSpace(finalThinking) != "" {
@@ -16,7 +16,7 @@ func BuildChatCompletion(completionID, model, finalPrompt, finalThinking, finalT
 	}
 	if len(detected.Calls) > 0 {
 		finishReason = "tool_calls"
-		messageObj["tool_calls"] = util.FormatOpenAIToolCalls(detected.Calls)
+		messageObj["tool_calls"] = toolcall.FormatOpenAIToolCalls(detected.Calls)
 		messageObj["content"] = nil
 	}
 

internal/format/openai/render_responses.go

@@ -1,19 +1,19 @@
 package openai
 
 import (
+	"ds2api/internal/toolcall"
 	"encoding/json"
 	"strings"
 	"time"
 
 	"github.com/google/uuid"
 
-	"ds2api/internal/util"
 )
 
 func BuildResponseObject(responseID, model, finalPrompt, finalThinking, finalText string, toolNames []string) map[string]any {
 	// Strict mode: only standalone, structured tool-call payloads are treated
 	// as executable tool calls.
-	detected := util.ParseStandaloneToolCallsDetailed(finalText, toolNames)
+	detected := toolcall.ParseStandaloneToolCallsDetailed(finalText, toolNames)
 	exposedOutputText := finalText
 	output := make([]any, 0, 2)
 	if len(detected.Calls) > 0 {
@@ -71,7 +71,7 @@ func BuildResponseObjectFromItems(responseID, model, finalPrompt, finalThinking,
 	}
 }
 
-func toResponsesFunctionCallItems(toolCalls []util.ParsedToolCall) []any {
+func toResponsesFunctionCallItems(toolCalls []toolcall.ParsedToolCall) []any {
 	if len(toolCalls) == 0 {
 		return nil
 	}

internal/toolcall/tool_prompt.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import "strings"
 

internal/toolcall/tool_prompt_test.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"strings"

internal/toolcall/toolcall_edge_test.go

@@ -0,0 +1,92 @@
+package toolcall
+
+import (
+	"testing"
+)
+
+// ─── FormatOpenAIStreamToolCalls ─────────────────────────────────────
+
+func TestFormatOpenAIStreamToolCalls(t *testing.T) {
+	formatted := FormatOpenAIStreamToolCalls([]ParsedToolCall{
+		{Name: "search", Input: map[string]any{"q": "test"}},
+	})
+	if len(formatted) != 1 {
+		t.Fatalf("expected 1, got %d", len(formatted))
+	}
+	fn, _ := formatted[0]["function"].(map[string]any)
+	if fn["name"] != "search" {
+		t.Fatalf("unexpected function name: %#v", fn)
+	}
+	if formatted[0]["index"] != 0 {
+		t.Fatalf("expected index 0, got %v", formatted[0]["index"])
+	}
+}
+
+// ─── ParseToolCalls more edge cases ──────────────────────────────────
+
+func TestParseToolCallsNoToolNames(t *testing.T) {
+	text := `{"tool_calls":[{"name":"search","input":{"q":"go"}}]}`
+	calls := ParseToolCalls(text, nil)
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 call with nil tool names, got %d", len(calls))
+	}
+}
+
+func TestParseToolCallsEmptyText(t *testing.T) {
+	calls := ParseToolCalls("", []string{"search"})
+	if len(calls) != 0 {
+		t.Fatalf("expected 0 calls for empty text, got %d", len(calls))
+	}
+}
+
+func TestParseToolCallsMultipleTools(t *testing.T) {
+	text := `{"tool_calls":[{"name":"search","input":{"q":"go"}},{"name":"get_weather","input":{"city":"beijing"}}]}`
+	calls := ParseToolCalls(text, []string{"search", "get_weather"})
+	if len(calls) != 2 {
+		t.Fatalf("expected 2 calls, got %d", len(calls))
+	}
+}
+
+func TestParseToolCallsInputAsString(t *testing.T) {
+	text := `{"tool_calls":[{"name":"search","input":"{\"q\":\"golang\"}"}]}`
+	calls := ParseToolCalls(text, []string{"search"})
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 call, got %d", len(calls))
+	}
+	if calls[0].Input["q"] != "golang" {
+		t.Fatalf("expected parsed string input, got %#v", calls[0].Input)
+	}
+}
+
+func TestParseToolCallsWithFunctionWrapper(t *testing.T) {
+	text := `{"tool_calls":[{"function":{"name":"calc","arguments":{"x":1,"y":2}}}]}`
+	calls := ParseToolCalls(text, []string{"calc"})
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 call, got %d", len(calls))
+	}
+	if calls[0].Name != "calc" {
+		t.Fatalf("expected calc, got %q", calls[0].Name)
+	}
+}
+
+func TestParseStandaloneToolCallsFencedCodeBlock(t *testing.T) {
+	fenced := "Here's an example:\n```json\n{\"tool_calls\":[{\"name\":\"search\",\"input\":{\"q\":\"go\"}}]}\n```\nDon't execute this."
+	calls := ParseStandaloneToolCalls(fenced, []string{"search"})
+	if len(calls) != 0 {
+		t.Fatalf("expected fenced code block to be ignored, got %d calls", len(calls))
+	}
+}
+
+// ─── looksLikeToolExampleContext ─────────────────────────────────────
+
+func TestLooksLikeToolExampleContextNone(t *testing.T) {
+	if looksLikeToolExampleContext("I will call the tool now") {
+		t.Fatal("expected false for non-example context")
+	}
+}
+
+func TestLooksLikeToolExampleContextFenced(t *testing.T) {
+	if !looksLikeToolExampleContext("```json") {
+		t.Fatal("expected true for fenced code block context")
+	}
+}

internal/toolcall/toolcalls_candidates.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"regexp"

internal/toolcall/toolcalls_format.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"encoding/json"

internal/toolcall/toolcalls_input_parse.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"encoding/json"

internal/toolcall/toolcalls_json_repair.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"regexp"

internal/toolcall/toolcalls_markup.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"encoding/json"

internal/toolcall/toolcalls_name_match.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"regexp"

internal/toolcall/toolcalls_parse.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"encoding/json"

internal/toolcall/toolcalls_parse_item.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import "strings"
 

internal/toolcall/toolcalls_parse_markup.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"encoding/json"

internal/toolcall/toolcalls_test.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"strings"

internal/toolcall/toolcalls_textkv.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"regexp"

internal/toolcall/toolcalls_textkv_test.go

@@ -1,4 +1,4 @@
-package util
+package toolcall
 
 import (
 	"testing"

internal/util/render.go

@@ -1,6 +1,7 @@
 package util
 
 import (
+	"ds2api/internal/toolcall"
 	"fmt"
 	"strings"
 	"time"
@@ -11,7 +12,7 @@ import (
 // BuildOpenAIChatCompletion is kept for backward compatibility.
 // Prefer internal/format/openai.BuildChatCompletion for new code.
 func BuildOpenAIChatCompletion(completionID, model, finalPrompt, finalThinking, finalText string, toolNames []string) map[string]any {
-	detected := ParseToolCalls(finalText, toolNames)
+	detected := toolcall.ParseToolCalls(finalText, toolNames)
 	finishReason := "stop"
 	messageObj := map[string]any{"role": "assistant", "content": finalText}
 	if strings.TrimSpace(finalThinking) != "" {
@@ -19,7 +20,7 @@ func BuildOpenAIChatCompletion(completionID, model, finalPrompt, finalThinking,
 	}
 	if len(detected) > 0 {
 		finishReason = "tool_calls"
-		messageObj["tool_calls"] = FormatOpenAIToolCalls(detected)
+		messageObj["tool_calls"] = toolcall.FormatOpenAIToolCalls(detected)
 		messageObj["content"] = nil
 	}
 	promptTokens := EstimateTokens(finalPrompt)
@@ -46,7 +47,7 @@ func BuildOpenAIChatCompletion(completionID, model, finalPrompt, finalThinking,
 // BuildOpenAIResponseObject is kept for backward compatibility.
 // Prefer internal/format/openai.BuildResponseObject for new code.
 func BuildOpenAIResponseObject(responseID, model, finalPrompt, finalThinking, finalText string, toolNames []string) map[string]any {
-	detected := ParseToolCalls(finalText, toolNames)
+	detected := toolcall.ParseToolCalls(finalText, toolNames)
 	exposedOutputText := finalText
 	output := make([]any, 0, 2)
 	if len(detected) > 0 {
@@ -56,9 +57,9 @@ func BuildOpenAIResponseObject(responseID, model, finalPrompt, finalThinking, fi
 		toolCalls := make([]any, 0, len(detected))
 		for _, tc := range detected {
 			toolCalls = append(toolCalls, map[string]any{
-				"type":      "tool_call",
-				"name":      tc.Name,
-				"arguments": tc.Input,
+				"type":       "tool_call",
+				"name":       tc.Name,
+				"arguments":  tc.Input,
 			})
 		}
 		output = append(output, map[string]any{
@@ -108,7 +109,7 @@ func BuildOpenAIResponseObject(responseID, model, finalPrompt, finalThinking, fi
 // BuildClaudeMessageResponse is kept for backward compatibility.
 // Prefer internal/format/claude.BuildMessageResponse for new code.
 func BuildClaudeMessageResponse(messageID, model string, normalizedMessages []any, finalThinking, finalText string, toolNames []string) map[string]any {
-	detected := ParseToolCalls(finalText, toolNames)
+	detected := toolcall.ParseToolCalls(finalText, toolNames)
 	content := make([]map[string]any, 0, 4)
 	if finalThinking != "" {
 		content = append(content, map[string]any{"type": "thinking", "thinking": finalThinking})

internal/util/util_edge_test.go

@@ -356,89 +356,3 @@ func TestConvertClaudeToDeepSeekOpusUsesSlowMapping(t *testing.T) {
 	}
 }
 
-// ─── FormatOpenAIStreamToolCalls ─────────────────────────────────────
-
-func TestFormatOpenAIStreamToolCalls(t *testing.T) {
-	formatted := FormatOpenAIStreamToolCalls([]ParsedToolCall{
-		{Name: "search", Input: map[string]any{"q": "test"}},
-	})
-	if len(formatted) != 1 {
-		t.Fatalf("expected 1, got %d", len(formatted))
-	}
-	fn, _ := formatted[0]["function"].(map[string]any)
-	if fn["name"] != "search" {
-		t.Fatalf("unexpected function name: %#v", fn)
-	}
-	if formatted[0]["index"] != 0 {
-		t.Fatalf("expected index 0, got %v", formatted[0]["index"])
-	}
-}
-
-// ─── ParseToolCalls more edge cases ──────────────────────────────────
-
-func TestParseToolCallsNoToolNames(t *testing.T) {
-	text := `{"tool_calls":[{"name":"search","input":{"q":"go"}}]}`
-	calls := ParseToolCalls(text, nil)
-	if len(calls) != 1 {
-		t.Fatalf("expected 1 call with nil tool names, got %d", len(calls))
-	}
-}
-
-func TestParseToolCallsEmptyText(t *testing.T) {
-	calls := ParseToolCalls("", []string{"search"})
-	if len(calls) != 0 {
-		t.Fatalf("expected 0 calls for empty text, got %d", len(calls))
-	}
-}
-
-func TestParseToolCallsMultipleTools(t *testing.T) {
-	text := `{"tool_calls":[{"name":"search","input":{"q":"go"}},{"name":"get_weather","input":{"city":"beijing"}}]}`
-	calls := ParseToolCalls(text, []string{"search", "get_weather"})
-	if len(calls) != 2 {
-		t.Fatalf("expected 2 calls, got %d", len(calls))
-	}
-}
-
-func TestParseToolCallsInputAsString(t *testing.T) {
-	text := `{"tool_calls":[{"name":"search","input":"{\"q\":\"golang\"}"}]}`
-	calls := ParseToolCalls(text, []string{"search"})
-	if len(calls) != 1 {
-		t.Fatalf("expected 1 call, got %d", len(calls))
-	}
-	if calls[0].Input["q"] != "golang" {
-		t.Fatalf("expected parsed string input, got %#v", calls[0].Input)
-	}
-}
-
-func TestParseToolCallsWithFunctionWrapper(t *testing.T) {
-	text := `{"tool_calls":[{"function":{"name":"calc","arguments":{"x":1,"y":2}}}]}`
-	calls := ParseToolCalls(text, []string{"calc"})
-	if len(calls) != 1 {
-		t.Fatalf("expected 1 call, got %d", len(calls))
-	}
-	if calls[0].Name != "calc" {
-		t.Fatalf("expected calc, got %q", calls[0].Name)
-	}
-}
-
-func TestParseStandaloneToolCallsFencedCodeBlock(t *testing.T) {
-	fenced := "Here's an example:\n```json\n{\"tool_calls\":[{\"name\":\"search\",\"input\":{\"q\":\"go\"}}]}\n```\nDon't execute this."
-	calls := ParseStandaloneToolCalls(fenced, []string{"search"})
-	if len(calls) != 0 {
-		t.Fatalf("expected fenced code block to be ignored, got %d calls", len(calls))
-	}
-}
-
-// ─── looksLikeToolExampleContext ─────────────────────────────────────
-
-func TestLooksLikeToolExampleContextNone(t *testing.T) {
-	if looksLikeToolExampleContext("I will call the tool now") {
-		t.Fatal("expected false for non-example context")
-	}
-}
-
-func TestLooksLikeToolExampleContextFenced(t *testing.T) {
-	if !looksLikeToolExampleContext("```json") {
-		t.Fatal("expected true for fenced code block context")
-	}
-}