fix: parse claude tool_use function/parameter format

internal/util/toolcalls_parse_markup.go

@@ -15,6 +15,7 @@ var antmlArgumentPattern = regexp.MustCompile(`(?is)<(?:[a-z0-9_]+:)?argument\s+
 var antmlParametersPattern = regexp.MustCompile(`(?is)<(?:[a-z0-9_]+:)?parameters\s*>\s*(\{.*?\})\s*</(?:[a-z0-9_]+:)?parameters>`)
 var invokeCallPattern = regexp.MustCompile(`(?is)<invoke\s+name="([^"]+)"\s*>(.*?)</invoke>`)
 var invokeParamPattern = regexp.MustCompile(`(?is)<parameter\s+name="([^"]+)"\s*>\s*(.*?)\s*</parameter>`)
+var toolUseFunctionPattern = regexp.MustCompile(`(?is)<tool_use>\s*<function\s+name="([^"]+)"\s*>(.*?)</function>\s*</tool_use>`)
 
 func parseXMLToolCalls(text string) []ParsedToolCall {
 	matches := xmlToolCallPattern.FindAllString(text, -1)
@@ -38,6 +39,9 @@ func parseXMLToolCalls(text string) []ParsedToolCall {
 	if call, ok := parseInvokeFunctionCallStyle(text); ok {
 		return []ParsedToolCall{call}
 	}
+	if call, ok := parseToolUseFunctionStyle(text); ok {
+		return []ParsedToolCall{call}
+	}
 	return nil
 }
 
@@ -229,6 +233,30 @@ func parseInvokeFunctionCallStyle(text string) (ParsedToolCall, bool) {
 	return ParsedToolCall{Name: name, Input: input}, true
 }
 
+func parseToolUseFunctionStyle(text string) (ParsedToolCall, bool) {
+	m := toolUseFunctionPattern.FindStringSubmatch(text)
+	if len(m) < 3 {
+		return ParsedToolCall{}, false
+	}
+	name := strings.TrimSpace(m[1])
+	if name == "" {
+		return ParsedToolCall{}, false
+	}
+	body := m[2]
+	input := map[string]any{}
+	for _, pm := range invokeParamPattern.FindAllStringSubmatch(body, -1) {
+		if len(pm) < 3 {
+			continue
+		}
+		k := strings.TrimSpace(pm[1])
+		v := strings.TrimSpace(pm[2])
+		if k != "" {
+			input[k] = v
+		}
+	}
+	return ParsedToolCall{Name: name, Input: input}, true
+}
+
 func asString(v any) string {
 	s, _ := v.(string)
 	return s

internal/util/toolcalls_test.go

@@ -236,6 +236,20 @@ func TestParseToolCallsSupportsInvokeFunctionCallStyle(t *testing.T) {
 	}
 }
 
+func TestParseToolCallsSupportsToolUseFunctionParameterStyle(t *testing.T) {
+	text := `<tool_use><function name="search_web"><parameter name="query">test</parameter></function></tool_use>`
+	calls := ParseToolCalls(text, []string{"search_web"})
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 call, got %#v", calls)
+	}
+	if calls[0].Name != "search_web" {
+		t.Fatalf("expected canonical tool name search_web, got %q", calls[0].Name)
+	}
+	if calls[0].Input["query"] != "test" {
+		t.Fatalf("expected query argument, got %#v", calls[0].Input)
+	}
+}
+
 func TestParseToolCallsSupportsNestedToolTagStyle(t *testing.T) {
 	text := `<tool_call><tool name="Bash"><command>pwd</command><description>show cwd</description></tool></tool_call>`
 	calls := ParseToolCalls(text, []string{"bash"})