From 998ca72c274898f32363f4141b7ebb6de889e8de Mon Sep 17 00:00:00 2001
From: Charles Howard <96023061+charlesrhoward@users.noreply.github.com>
Date: Sat, 21 Feb 2026 16:24:44 -0500
Subject: [PATCH 1/2] perf: use incremental chat message fingerprinting

---
 components/ai-chat-panel.tsx | 38 ++++++++++++++++++++++++++++++------
 1 file changed, 32 insertions(+), 6 deletions(-)

diff --git a/components/ai-chat-panel.tsx b/components/ai-chat-panel.tsx
index 0d8510d..a123c67 100644
--- a/components/ai-chat-panel.tsx
+++ b/components/ai-chat-panel.tsx
@@ -436,12 +436,38 @@ export function AIChatPanel({ canvasDimensions }: AIChatPanelProps) {
   }, [])
 
   const getMessagesFingerprint = useCallback((msgs: UIMessage[]) => {
-    return JSON.stringify(
-      msgs.map((msg) => ({
-        id: msg.id,
-        ...chatService.convertToDbMessage(msg),
-      })),
-    )
+    if (msgs.length === 0) return "empty"
+
+    const last = msgs[msgs.length - 1]
+    const lastWithMeta = last as UIMessage & { content?: string; createdAt?: Date | string }
+
+    let textPartLength = 0
+    let filePartCount = 0
+    let reasoningPartCount = 0
+    for (const part of last.parts || []) {
+      if (part.type === "text") {
+        textPartLength += part.text.length
+      } else if (part.type === "file") {
+        filePartCount += 1
+      } else if (part.type === "reasoning") {
+        reasoningPartCount += 1
+      }
+    }
+
+    const createdAt =
+      lastWithMeta.createdAt instanceof Date ? lastWithMeta.createdAt.toISOString() : (lastWithMeta.createdAt ?? "")
+
+    return [
+      msgs.length,
+      last.id,
+      last.role,
+      createdAt,
+      lastWithMeta.content?.length ?? 0,
+      last.parts?.length ?? 0,
+      textPartLength,
+      filePartCount,
+      reasoningPartCount,
+    ].join("|")
   }, [])
 
   useLoadChatHistory({

From f72af4c87edafe6068d585cfd1c21c06b992fbc6 Mon Sep 17 00:00:00 2001
From: Charles Howard <96023061+charlesrhoward@users.noreply.github.com>
Date: Sat, 21 Feb 2026 16:54:39 -0500
Subject: [PATCH 2/2] chore: retrigger checks for PR #40