diff --git a/packages/opencode/src/provider/error.ts b/packages/opencode/src/provider/error.ts
index 3877dcb7f304..d0511a1d5ded 100644
--- a/packages/opencode/src/provider/error.ts
+++ b/packages/opencode/src/provider/error.ts
@@ -123,7 +123,10 @@ export function parseStreamError(input: unknown): ParsedStreamError | undefined
   const responseBody = JSON.stringify(body)
   if (body.type !== "error") return
 
-  switch (body?.error?.code) {
+  const errorCode = typeof body?.error?.code === "string" ? body.error.code : ""
+  const errorType = typeof body?.error?.type === "string" ? body.error.type : ""
+
+  switch (errorCode) {
     case "context_length_exceeded":
       return {
         type: "context_overflow",
@@ -159,6 +162,20 @@ export function parseStreamError(input: unknown): ParsedStreamError | undefined
         responseBody,
       }
   }
+
+  if (
+    errorType === "service_unavailable_error" ||
+    errorCode === "server_is_overloaded" ||
+    errorCode.includes("unavailable") ||
+    errorCode.includes("exhausted")
+  ) {
+    return {
+      type: "api_error",
+      message: typeof body?.error?.message === "string" ? body.error.message : "Provider is overloaded",
+      isRetryable: true,
+      responseBody,
+    }
+  }
 }
 
 export type ParsedAPICallError =
diff --git a/packages/opencode/test/session/retry.test.ts b/packages/opencode/test/session/retry.test.ts
index 105c772d9735..bbfaf83d594c 100644
--- a/packages/opencode/test/session/retry.test.ts
+++ b/packages/opencode/test/session/retry.test.ts
@@ -323,4 +323,27 @@ describe("session.message-v2.fromError", () => {
     expect(result.data.isRetryable).toBe(true)
     expect(SessionRetry.retryable(result)).toBe("An error occurred while processing your request.")
   })
+
+  test("converts OpenAI overloaded stream chunks to retryable APIError", () => {
+    const result = MessageV2.fromError(
+      {
+        message: JSON.stringify({
+          type: "error",
+          sequence_number: 2,
+          error: {
+            type: "service_unavailable_error",
+            code: "server_is_overloaded",
+            message: "Our servers are currently overloaded. Please try again later.",
+            param: null,
+          },
+        }),
+      },
+      { providerID: ProviderID.make("openai") },
+    )
+
+    expect(MessageV2.APIError.isInstance(result)).toBe(true)
+    if (!MessageV2.APIError.isInstance(result)) throw new Error("expected APIError")
+    expect(result.data.isRetryable).toBe(true)
+    expect(SessionRetry.retryable(result)).toBe("Our servers are currently overloaded. Please try again later.")
+  })
 })