From 1593c3ed16369001f24252d0091092da8db26bf3 Mon Sep 17 00:00:00 2001
From: Kit Langton <kit.langton@gmail.com>
Date: Tue, 21 Apr 2026 23:28:33 -0400
Subject: [PATCH] refactor(core): migrate MessageV2 internal Cursor to Effect
 Schema (#23763)

---
 packages/opencode/src/session/message-v2.ts | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index f1cb6db218..aceecd9b8c 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -638,18 +638,20 @@ export type WithParts = {
   parts: Part[]
 }
 
-const Cursor = z.object({
-  id: MessageID.zod,
-  time: z.number(),
+const Cursor = Schema.Struct({
+  id: MessageID,
+  time: Schema.Number,
 })
-type Cursor = z.infer<typeof Cursor>
+type Cursor = typeof Cursor.Type
+
+const decodeCursor = Schema.decodeUnknownSync(Cursor)
 
 export const cursor = {
   encode(input: Cursor) {
     return Buffer.from(JSON.stringify(input)).toString("base64url")
   },
   decode(input: string) {
-    return Cursor.parse(JSON.parse(Buffer.from(input, "base64url").toString("utf8")))
+    return decodeCursor(JSON.parse(Buffer.from(input, "base64url").toString("utf8")))
   },
 }