diff --git a/package-lock.json b/package-lock.json
index 9358015..ced4e7f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -396,6 +396,7 @@
       "resolved": "https://registry.npmjs.org/express/-/express-5.2.1.tgz",
       "integrity": "sha512-hIS4idWWai69NezIdRt2xFVofaF4j+6INOpJlVOLDO8zXGpUVEVzIYk12UUi2JzjEzWL3IOAxcTubgz9Po0yXw==",
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "accepts": "^2.0.0",
         "body-parser": "^2.2.1",
@@ -600,6 +601,7 @@
       "resolved": "https://registry.npmjs.org/hono/-/hono-4.11.7.tgz",
       "integrity": "sha512-l7qMiNee7t82bH3SeyUCt9UF15EVmaBvsppY2zQtrbIhl/yzBTny+YUxsVjSjQ6gaqaeVtZmGocom8TzBlA4Yw==",
       "license": "MIT",
+      "peer": true,
       "engines": {
         "node": ">=16.9.0"
       }
@@ -1170,6 +1172,7 @@
       "resolved": "https://registry.npmjs.org/zod/-/zod-4.3.6.tgz",
       "integrity": "sha512-rftlrkhHZOcjDwkGlnUtZZkvaPHCsDATp4pGpuOOMDaTdDDXF91wuVDJoWoPsKX/3YPQ5fHuF3STjcYyKr+Qhg==",
       "license": "MIT",
+      "peer": true,
       "funding": {
         "url": "https://github.com/sponsors/colinhacks"
       }
diff --git a/src/index.ts b/src/index.ts
index 064a6c8..a12c45d 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -10,7 +10,7 @@ import { XMCPServer } from './mcp/server.js';
 async function main() {
   // Redirect console.log to stderr so it doesn't conflict with
   // MCP StdioServerTransport which uses stdout for protocol messages
-  console.log = (...args: any[]) => console.error(...args);
+  console.log = (...args: unknown[]) => console.error(...args);
 
   console.log('═══════════════════════════════════════════════════');
   console.log('  MyXstack - Autonomous AI Agent on X (Twitter)');
diff --git a/src/services/agent.ts b/src/services/agent.ts
index de10ae7..bbe7556 100644
--- a/src/services/agent.ts
+++ b/src/services/agent.ts
@@ -91,8 +91,9 @@ export class AutonomousAgent {
 
       console.log(`\n📬 [${new Date().toLocaleTimeString()}] Found ${newMentions.length} new mention(s)!\n`);
 
-      // Process each mention
-      for (const mention of newMentions) {
+      // Process mentions oldest-first (API returns newest-first) so Set
+      // insertion order is chronological and oldest entries are pruned first
+      for (const mention of [...newMentions].reverse()) {
         await this.processMention(mention);
         this.processedMentions.add(mention.post.id);
       }
@@ -102,7 +103,11 @@ export class AutonomousAgent {
         const excess = this.processedMentions.size - AutonomousAgent.MAX_PROCESSED_MENTIONS;
         const iter = this.processedMentions.values();
         for (let i = 0; i < excess; i++) {
-          this.processedMentions.delete(iter.next().value as string);
+          const { value, done } = iter.next();
+          if (done) {
+            break;
+          }
+          this.processedMentions.delete(value);
         }
       }
     } catch (error) {
diff --git a/src/services/grok.ts b/src/services/grok.ts
index d71ffdc..52c239c 100644
--- a/src/services/grok.ts
+++ b/src/services/grok.ts
@@ -59,7 +59,7 @@ export class GrokService {
         throw new Error(`Grok API error: ${response.status}`);
       }
 
-      const data: any = await response.json();
+      const data = await response.json() as { choices: { message?: { content?: string } }[] };
       const analysisText = data.choices[0]?.message?.content || '';
       
       // Use the mention post ID so replies target the specific post where the agent was mentioned
diff --git a/src/services/xapi.ts b/src/services/xapi.ts
index ab6c4b5..968d3db 100644
--- a/src/services/xapi.ts
+++ b/src/services/xapi.ts
@@ -44,10 +44,15 @@ export class XAPIClient {
         throw new Error('Failed to get user ID from response');
       }
 
-      let mentionsUrl = `https://api.twitter.com/2/users/${userId}/mentions?max_results=10&expansions=author_id&tweet.fields=created_at,conversation_id,in_reply_to_user_id,referenced_tweets`;
+      const params = new URLSearchParams({
+        max_results: '10',
+        expansions: 'author_id',
+        'tweet.fields': 'created_at,conversation_id,in_reply_to_user_id,referenced_tweets',
+      });
       if (this.lastMentionId) {
-        mentionsUrl += `&since_id=${this.lastMentionId}`;
+        params.set('since_id', this.lastMentionId);
       }
+      const mentionsUrl = `https://api.twitter.com/2/users/${userId}/mentions?${params.toString()}`;
 
       const mentionsResponse = await this.makeXAPIRequest(mentionsUrl, 'GET');
 
@@ -91,6 +96,11 @@ export class XAPIClient {
         return null;
       }
 
+      if (!Array.isArray(response.data)) {
+        console.warn('Unexpected response shape from X API (thread): data is not an array');
+        return null;
+      }
+
       return this.parseThread(response.data);
     } catch (error) {
       console.error('Error fetching thread:', error);