Update MCP return description to clarify content vs spec usage (#275)

* Initial plan

* Update MCP return description text to clarify content and spec usage

Co-authored-by: hustcc <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: hustcc <[email protected]>

Author: Copilot

__tests__/server.spec.ts

@@ -60,7 +60,7 @@ describe("MCP Server", () => {
 
     expect(res._meta).toEqual({
       description:
-        "This is the chart's spec and configuration, which can be renderred to corresponding chart by AntV GPT-Vis chart components.",
+        "The content returned by MCP is the remote image URL of the visualization chart, which can be rendered using Markdown or HTML image tags. The _meta.spec content corresponds to the chart's configuration and spec, which can be rendered using AntV GPT-Vis chart components.",
       spec: spec,
     });
 
@@ -103,7 +103,7 @@ describe("MCP Server", () => {
 
     expect(res._meta).toEqual({
       description:
-        "This is the chart's spec and configuration, which can be renderred to corresponding chart by AntV GPT-Vis chart components.",
+        "The content returned by MCP is the remote image URL of the visualization chart, which can be rendered using Markdown or HTML image tags. The _meta.spec content corresponds to the chart's configuration and spec, which can be rendered using AntV GPT-Vis chart components.",
       spec: spec,
     });
 
@@ -150,7 +150,7 @@ describe("MCP Server", () => {
 
     expect(res._meta).toEqual({
       description:
-        "This is the chart's spec and configuration, which can be renderred to corresponding chart by AntV GPT-Vis chart components.",
+        "The content returned by MCP is the remote image URL of the visualization chart, which can be rendered using Markdown or HTML image tags. The _meta.spec content corresponds to the chart's configuration and spec, which can be rendered using AntV GPT-Vis chart components.",
       spec: spec,
     });
 

src/utils/callTool.ts

@@ -102,7 +102,7 @@ export async function callTool(tool: string, args: object = {}) {
       ],
       _meta: {
         description:
-          "This is the chart's spec and configuration, which can be renderred to corresponding chart by AntV GPT-Vis chart components.",
+          "The content returned by MCP is the remote image URL of the visualization chart, which can be rendered using Markdown or HTML image tags. The _meta.spec content corresponds to the chart's configuration and spec, which can be rendered using AntV GPT-Vis chart components.",
         spec: { type: chartType, ...args },
       },
     };