fix: remove unused think property from serpCluster schema

Author: hanxiao

src/tools/serp-cluster.ts

@@ -29,7 +29,6 @@ export async function serpCluster(results: SearchSnippet[], trackers: TrackerCon
       system: prompt.system,
       prompt: prompt.user,
     });
-    trackers?.actionTracker.trackThink(result.object.think);
     const clusters = result.object.clusters;
     logInfo(TOOL_NAME, { clusters });
     return clusters;

src/utils/schemas.ts

@@ -176,7 +176,6 @@ export class Schemas {
 
   getSerpClusterSchema(): z.ZodObject<any> {
     return z.object({
-      think: z.string().describe(`Explain why you cluster the search results like this. ${this.getLanguagePrompt()}`).max(500),
       clusters: z.array(
         z.object({
           insight: z.string().describe('Summary and list key numbers, data, soundbites, and insights that worth to be highlighted. End with an actionable advice such as "Visit these URLs if you want to understand [what...]". Do not use "This cluster..."').max(200),