LLM 请求透明化

Co-authored-by: Copilot <copilot@github.com>

.opencode/tools/show_chart.ts

@@ -3,6 +3,9 @@ import { tool } from "@opencode-ai/plugin";
 export default tool({
   description: "在前端对话界面中渲染图表。",
   args: {
+    reason: tool.schema
+      .string()
+      .describe("Why this chart should be rendered for the user request."),
     title: tool.schema.string().optional().describe("Chart title."),
     chart_type: tool.schema
       .enum(["line", "bar", "pie"])