fix: preserve reasoning in short-term memory replay

src/core/agent-reasoning-memory.test.ts

@@ -0,0 +1,63 @@
+import { describe, expect, it } from 'vitest';
+
+type MemoryEntry = {
+  role: 'user' | 'assistant' | 'system';
+  content: string;
+  reasoning?: string;
+};
+
+function toModelMessages(recentMemory: MemoryEntry[]) {
+  const messages: any[] = [];
+
+  if (recentMemory.length > 0) {
+    for (const m of recentMemory) {
+      if (m.role === 'assistant' && m.reasoning) {
+        messages.push({
+          role: 'assistant',
+          content: [
+            { type: 'reasoning', text: m.reasoning },
+            { type: 'text', text: m.content },
+          ],
+        });
+        continue;
+      }
+
+      messages.push({
+        role: m.role === 'user' ? 'user' : 'assistant',
+        content: m.content,
+      });
+    }
+  }
+
+  return messages;
+}
+
+describe('assistant reasoning is preserved in replayed short-term memory', () => {
+  it('replays assistant reasoning alongside assistant text when available', () => {
+    const messages = toModelMessages([
+      { role: 'user', content: 'hello' },
+      { role: 'assistant', content: 'world', reasoning: 'think-step' },
+    ]);
+
+    expect(messages).toEqual([
+      { role: 'user', content: 'hello' },
+      {
+        role: 'assistant',
+        content: [
+          { type: 'reasoning', text: 'think-step' },
+          { type: 'text', text: 'world' },
+        ],
+      },
+    ]);
+  });
+
+  it('keeps assistant messages as plain text when no reasoning exists', () => {
+    const messages = toModelMessages([
+      { role: 'assistant', content: 'plain reply' },
+    ]);
+
+    expect(messages).toEqual([
+      { role: 'assistant', content: 'plain reply' },
+    ]);
+  });
+});

src/core/agent.ts

@@ -479,6 +479,17 @@ export class Agent {
 
       if (recentMemory.length > 0) {
         for (const m of recentMemory) {
+          if (m.role === 'assistant' && m.reasoning) {
+            messages.push({
+              role: 'assistant',
+              content: [
+                { type: 'reasoning', text: m.reasoning },
+                { type: 'text', text: m.content },
+              ],
+            });
+            continue;
+          }
+
           messages.push({
             role: m.role === 'user' ? 'user' : 'assistant',
             content: m.content,