diff --git a/pkg/agent/agent_utils.go b/pkg/agent/agent_utils.go
index bbfb3f2ae..2651fb2db 100644
--- a/pkg/agent/agent_utils.go
+++ b/pkg/agent/agent_utils.go
@@ -4,7 +4,6 @@ package agent
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"maps"
 	"path/filepath"
@@ -171,15 +170,8 @@ func toolFeedbackExplanationFromMessages(messages []providers.Message) string {
 }
 
 func toolFeedbackArgsPreview(args map[string]any, maxLen int) string {
-	if args == nil {
-		args = map[string]any{}
-	}
-
-	argsJSON, err := json.MarshalIndent(args, "", "  ")
-	if err != nil {
-		return utils.Truncate(fmt.Sprintf("%v", args), maxLen)
-	}
-	return utils.Truncate(string(argsJSON), maxLen)
+	argsJSON := utils.FormatArgsJSON(args, true, false)
+	return utils.Truncate(argsJSON, maxLen)
 }
 
 func shouldPublishToolFeedback(cfg *config.Config, ts *turnState) bool {
diff --git a/pkg/utils/tool_feedback.go b/pkg/utils/tool_feedback.go
index de7cb467e..1834d7f78 100644
--- a/pkg/utils/tool_feedback.go
+++ b/pkg/utils/tool_feedback.go
@@ -1,12 +1,35 @@
 package utils
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"strings"
 )
 
 const ToolFeedbackContinuationHint = "Continuing the current task."
 
+func FormatArgsJSON(args map[string]any, prettyPrint, disableEscapeHTML bool) string {
+	// Normalize nil to empty map for consistent output
+	if args == nil {
+		args = map[string]any{}
+	}
+
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	if prettyPrint {
+		enc.SetIndent("", "  ")
+	}
+	if disableEscapeHTML {
+		enc.SetEscapeHTML(false)
+	}
+	if err := enc.Encode(args); err != nil {
+		// Fallback to fmt.Sprintf to preserve visibility of problematic args
+		return fmt.Sprintf("%v", args)
+	}
+	return strings.TrimSpace(buf.String())
+}
+
 // FormatToolFeedbackMessage renders a tool feedback message for chat channels.
 // It keeps the tool name on the first line for animation and can include both
 // a human explanation and the serialized tool arguments in the body.
diff --git a/pkg/utils/tool_feedback_test.go b/pkg/utils/tool_feedback_test.go
index c30f53827..da4accce4 100644
--- a/pkg/utils/tool_feedback_test.go
+++ b/pkg/utils/tool_feedback_test.go
@@ -1,6 +1,9 @@
 package utils
 
-import "testing"
+import (
+	"encoding/json"
+	"testing"
+)
 
 func TestFormatToolFeedbackMessage(t *testing.T) {
 	got := FormatToolFeedbackMessage(
@@ -56,3 +59,98 @@ func TestFitToolFeedbackMessage_TruncatesSingleLineMessage(t *testing.T) {
 		t.Fatalf("FitToolFeedbackMessage() = %q, want %q", got, want)
 	}
 }
+
+func TestFormatArgsJSON_Defaults(t *testing.T) {
+	args := map[string]any{"path": "README.md", "line": 42}
+	got := FormatArgsJSON(args, false, false)
+	var gotVal, wantVal any
+	if err := json.Unmarshal([]byte(got), &gotVal); err != nil {
+		t.Fatalf("FormatArgsJSON() returned invalid JSON: %v", err)
+	}
+	want := `{"path":"README.md","line":42}`
+	if err := json.Unmarshal([]byte(want), &wantVal); err != nil {
+		t.Fatalf("invalid test want JSON: %v", err)
+	}
+	if !jsonValEq(gotVal, wantVal) {
+		t.Fatalf("FormatArgsJSON() = %q, want %q", got, want)
+	}
+}
+
+func TestFormatArgsJSON_PrettyPrint(t *testing.T) {
+	args := map[string]any{"path": "README.md", "line": 42}
+	got := FormatArgsJSON(args, true, false)
+	var gotVal any
+	if err := json.Unmarshal([]byte(got), &gotVal); err != nil {
+		t.Fatalf("FormatArgsJSON() returned invalid JSON: %v", err)
+	}
+	want := `{"path":"README.md","line":42}`
+	var wantVal any
+	if err := json.Unmarshal([]byte(want), &wantVal); err != nil {
+		t.Fatalf("invalid test want JSON: %v", err)
+	}
+	if !jsonValEq(gotVal, wantVal) {
+		t.Fatalf("FormatArgsJSON() prettyPrint = %q, want structure %q", got, want)
+	}
+}
+
+func TestFormatArgsJSON_DisableEscapeHTML(t *testing.T) {
+	args := map[string]any{"msg": "a < b && c > d"}
+	got := FormatArgsJSON(args, false, true)
+	var gotVal, wantVal any
+	want := `{"msg":"a < b && c > d"}`
+	if err := json.Unmarshal([]byte(got), &gotVal); err != nil {
+		t.Fatalf("FormatArgsJSON() returned invalid JSON: %v", err)
+	}
+	if err := json.Unmarshal([]byte(want), &wantVal); err != nil {
+		t.Fatalf("invalid test want JSON: %v", err)
+	}
+	if !jsonValEq(gotVal, wantVal) {
+		t.Fatalf("FormatArgsJSON() disableEscapeHTML = %q, want %q", got, want)
+	}
+}
+
+func TestFormatArgsJSON_PrettyPrintAndDisableEscapeHTML(t *testing.T) {
+	args := map[string]any{"msg": "a < b && c > d"}
+	got := FormatArgsJSON(args, true, true)
+	var gotVal, wantVal any
+	want := `{"msg":"a < b && c > d"}`
+	if err := json.Unmarshal([]byte(got), &gotVal); err != nil {
+		t.Fatalf("FormatArgsJSON() returned invalid JSON: %v", err)
+	}
+	if err := json.Unmarshal([]byte(want), &wantVal); err != nil {
+		t.Fatalf("invalid test want JSON: %v", err)
+	}
+	if !jsonValEq(gotVal, wantVal) {
+		t.Fatalf("FormatArgsJSON() combined = %q, want %q", got, want)
+	}
+}
+
+func TestFormatArgsJSON_EscapeHTMLByDefault(t *testing.T) {
+	args := map[string]any{"msg": "a < b && c > d"}
+	got := FormatArgsJSON(args, false, false)
+	var gotVal, wantVal any
+	want := `{"msg":"a \u003c b \u0026\u0026 c \u003e d"}`
+	if err := json.Unmarshal([]byte(got), &gotVal); err != nil {
+		t.Fatalf("FormatArgsJSON() returned invalid JSON: %v", err)
+	}
+	if err := json.Unmarshal([]byte(want), &wantVal); err != nil {
+		t.Fatalf("invalid test want JSON: %v", err)
+	}
+	if !jsonValEq(gotVal, wantVal) {
+		t.Fatalf("FormatArgsJSON() default escape = %q, want %q", got, want)
+	}
+}
+
+func TestFormatArgsJSON_NilArgs(t *testing.T) {
+	got := FormatArgsJSON(nil, false, false)
+	want := `{}`
+	if got != want {
+		t.Fatalf("FormatArgsJSON() nil = %q, want %q", got, want)
+	}
+}
+
+func jsonValEq(a, b any) bool {
+	aJSON, _ := json.Marshal(a)
+	bJSON, _ := json.Marshal(b)
+	return string(aJSON) == string(bJSON)
+}