@@ -124,7 +124,15 @@ export const baseTranscript = (input: {
         metadata: { experimental: { instructions: input.initial } },
       },
     ].filter((part) => part.text.length > 0),
-    messages: toLLMMessages(input.messages, input.model.ref, providerMetadataKey),
+    // Hooks read each stored message's metadata on the messages built from it; `prepare` strips it before the request.
+    messages: input.messages.flatMap((message) =>
+      toLLMMessages([message], input.model.ref, providerMetadataKey).map(
+        (item): SessionRequestMessage =>
+          message.metadata === undefined || item.id !== message.id
+            ? item
+            : Object.assign(item, { metadata: message.metadata }),
+      ),
+    ),
   }
 }
 
 
@@ -16,7 +16,6 @@ import { SessionMessage } from "../message.js"
 import { SessionHistory } from "../history.js"
 import { SessionRecentText } from "../recent-text.js"
 import type { FileAttachment } from "@opencode/schema/prompt"
-import type { SessionRequestMessage } from "@opencode/plugin/effect/session"
 
 const imageMimes = new Set(["image/png", "image/jpeg", "image/gif", "image/webp"])
 
@@ -313,20 +312,9 @@ function toLLMMessage(message: SessionMessage.Info, model: Model.Ref, providerMe
   }
 }
 
-/**
- * Translate projected Session history into canonical @opencode/ai context. Messages built from a stored message carry
- * its metadata for plugin hooks; SessionModelRequest strips it before the model request.
- */
+/** Translate projected Session history into canonical @opencode/ai context. */
 export const toLLMMessages = (
   messages: readonly SessionMessage.Info[],
   model: Model.Ref,
   providerMetadataKey: string = model.providerID,
-) =>
-  messages.flatMap((message) =>
-    toLLMMessage(message, model, providerMetadataKey).map(
-      (item): SessionRequestMessage =>
-        message.metadata === undefined || item.id !== message.id
-          ? item
-          : Object.assign(item, { metadata: message.metadata }),
-    ),
-  )
+) => messages.flatMap((message) => toLLMMessage(message, model, providerMetadataKey))
@@ -48,9 +48,7 @@ describe("toLLMMessages", () => {
     })
     expect(toLLMMessages([completed], model)).toEqual([])
     expect(toLLMMessages([completed, notification], model)).toEqual([
-      Object.assign(Message.make({ id: notification.id, role: "user", content: notification.text }), {
-        metadata: notification.metadata,
-      }),
+      Message.make({ id: notification.id, role: "user", content: notification.text }),
     ])
   })