diff --git a/pkg/tools/shell.go b/pkg/tools/shell.go
index 5c2b03f4f..018a77ac9 100644
--- a/pkg/tools/shell.go
+++ b/pkg/tools/shell.go
@@ -671,7 +671,10 @@ func (t *ExecTool) runBackground(ctx context.Context, command, cwd string, ptyEn
 		SessionID: sessionID,
 		Status:    "running",
 	}
-	data, _ := json.Marshal(resp)
+	data, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(data),
 		ForUser: fmt.Sprintf("Session %s started", sessionID),
@@ -684,7 +687,10 @@ func (t *ExecTool) executeList() *ToolResult {
 	resp := ExecResponse{
 		Sessions: sessions,
 	}
-	data, _ := json.Marshal(resp)
+	data, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(data),
 		ForUser: fmt.Sprintf("%d active sessions", len(sessions)),
@@ -711,7 +717,10 @@ func (t *ExecTool) executePoll(args map[string]any) *ToolResult {
 		Status:    session.GetStatus(),
 		ExitCode:  session.GetExitCode(),
 	}
-	data, _ := json.Marshal(resp)
+	data, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(data),
 		IsError: false,
@@ -739,7 +748,10 @@ func (t *ExecTool) executeRead(args map[string]any) *ToolResult {
 		Output:    output,
 		Status:    session.GetStatus(),
 	}
-	data, _ := json.Marshal(resp)
+	data, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(data),
 		IsError: false,
@@ -769,7 +781,7 @@ func (t *ExecTool) executeWrite(args map[string]any) *ToolResult {
 		return ErrorResult(fmt.Sprintf("process already exited with code %d", session.GetExitCode()))
 	}
 
-	if err := session.Write(data); err != nil {
+	if err = session.Write(data); err != nil {
 		if errors.Is(err, ErrSessionDone) {
 			return ErrorResult(fmt.Sprintf("process already exited with code %d", session.GetExitCode()))
 		}
@@ -780,7 +792,10 @@ func (t *ExecTool) executeWrite(args map[string]any) *ToolResult {
 		SessionID: sessionID,
 		Status:    session.GetStatus(),
 	}
-	respData, _ := json.Marshal(resp)
+	respData, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(respData),
 		IsError: false,
@@ -805,7 +820,7 @@ func (t *ExecTool) executeKill(args map[string]any) *ToolResult {
 		return ErrorResult(fmt.Sprintf("process already exited with code %d", session.GetExitCode()))
 	}
 
-	if err := session.Kill(); err != nil {
+	if err = session.Kill(); err != nil {
 		return ErrorResult(fmt.Sprintf("failed to kill session: %v", err))
 	}
 
@@ -815,7 +830,10 @@ func (t *ExecTool) executeKill(args map[string]any) *ToolResult {
 		SessionID: sessionID,
 		Status:    "done",
 	}
-	data, _ := json.Marshal(resp)
+	data, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(data),
 		ForUser: fmt.Sprintf("Session %s killed", sessionID),
@@ -1027,7 +1045,7 @@ func (t *ExecTool) executeSendKeys(args map[string]any) *ToolResult {
 		return ErrorResult(fmt.Sprintf("process already exited with code %d", session.GetExitCode()))
 	}
 
-	if err := session.Write(data); err != nil {
+	if err = session.Write(data); err != nil {
 		if errors.Is(err, ErrSessionDone) {
 			return ErrorResult(fmt.Sprintf("process already exited with code %d", session.GetExitCode()))
 		}
@@ -1039,7 +1057,10 @@ func (t *ExecTool) executeSendKeys(args map[string]any) *ToolResult {
 		Status:    "running",
 		Output:    fmt.Sprintf("Sent keys: %v", keys),
 	}
-	respData, _ := json.Marshal(resp)
+	respData, err := json.Marshal(resp)
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
 	return &ToolResult{
 		ForLLM:  string(respData),
 		IsError: false,