diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index edf881b13..77858fa03 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -616,6 +616,14 @@ export namespace MessageV2 {
       case APICallError.isInstance(e):
         const message = iife(() => {
           let msg = e.message
+          if (msg === "") {
+            if (e.responseBody) return e.responseBody
+            if (e.statusCode) {
+              const err = STATUS_CODES[e.statusCode]
+              if (err) return err
+            }
+            return "Unknown error"
+          }
           const transformed = ProviderTransform.error(ctx.providerID, e)
           if (transformed !== msg) {
             return transformed
@@ -634,7 +642,7 @@ export namespace MessageV2 {
           } catch {}
 
           return `${msg}: ${e.responseBody}`
-        })
+        }).trim()
 
         return new MessageV2.APIError(
           {