From 64ef85159db9918e1d6a955963a8ca7fa9636527 Mon Sep 17 00:00:00 2001
From: Kit Langton <kit.langton@gmail.com>
Date: Thu, 27 Aug 2026 23:01:33 -0400
Subject: [PATCH] fix(core): preserve assistant text metadata (#45650)

---
 .changeset/assistant-text-metadata.md |  5 +++++
 packages/core/src/aisdk.ts            |  2 +-
 packages/core/test/aisdk.test.ts      | 12 ++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/assistant-text-metadata.md

diff --git a/.changeset/assistant-text-metadata.md b/.changeset/assistant-text-metadata.md
new file mode 100644
index 00000000000..32645284b39
--- /dev/null
+++ b/.changeset/assistant-text-metadata.md
@@ -0,0 +1,5 @@
+---
+"@opencode-ai/core": patch
+---
+
+Preserve provider metadata on assistant text when replaying conversation history through AI SDK providers.
diff --git a/packages/core/src/aisdk.ts b/packages/core/src/aisdk.ts
index 96fe7d7a248..d44763d85ba 100644
--- a/packages/core/src/aisdk.ts
+++ b/packages/core/src/aisdk.ts
@@ -514,7 +514,7 @@ function userPart(part: ContentPart): UserContent {
 function assistantPart(part: ContentPart): AssistantContent {
   switch (part.type) {
     case "text":
-      return [{ type: "text", text: part.text }]
+      return [{ type: "text", text: part.text, providerOptions: metadataProviderOptions(part.providerMetadata) }]
     case "media":
       return [{ type: "file", mediaType: part.mediaType, data: part.data, filename: part.filename }]
     case "reasoning":
diff --git a/packages/core/test/aisdk.test.ts b/packages/core/test/aisdk.test.ts
index b9775603804..41c35530552 100644
--- a/packages/core/test/aisdk.test.ts
+++ b/packages/core/test/aisdk.test.ts
@@ -326,6 +326,8 @@ it.effect("projects replay metadata onto AI SDK prompt parts", () =>
         model: resolved,
         messages: [
           Message.assistant([
+            { type: "text", text: "Answer", providerMetadata: { anthropic: { cacheControl: { type: "ephemeral" } } } },
+            { type: "text", text: " without metadata" },
             { type: "reasoning", text: "Think", providerMetadata: { anthropic: { signature: "signed" } } },
             {
               type: "tool-call",
@@ -344,6 +346,16 @@ it.effect("projects replay metadata onto AI SDK prompt parts", () =>
       {
         role: "assistant",
         content: [
+          {
+            type: "text",
+            text: "Answer",
+            providerOptions: { anthropic: { cacheControl: { type: "ephemeral" } } },
+          },
+          {
+            type: "text",
+            text: " without metadata",
+            providerOptions: undefined,
+          },
           {
             type: "reasoning",
             text: "Think",