diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 9a955f5c..94d2861c 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -3,77 +3,21 @@ import { unique } from "remeda"
 import type { JSONSchema } from "zod/v4/core"
 
 export namespace ProviderTransform {
-  function normalizeMessages(
-    msgs: ModelMessage[],
-    providerID: string,
-    modelID: string,
-  ): ModelMessage[] {
-    if (modelID.includes("claude")) {
-      return msgs.map((msg) => {
-        if ((msg.role === "assistant" || msg.role === "tool") && Array.isArray(msg.content)) {
-          msg.content = msg.content.map((part) => {
-            if (
-              (part.type === "tool-call" || part.type === "tool-result") &&
-              "toolCallId" in part
-            ) {
-              return {
-                ...part,
-                toolCallId: part.toolCallId.replace(/[^a-zA-Z0-9_-]/g, "_"),
-              }
+  function normalizeToolCallIds(msgs: ModelMessage[]): ModelMessage[] {
+    return msgs.map((msg) => {
+      if ((msg.role === "assistant" || msg.role === "tool") && Array.isArray(msg.content)) {
+        msg.content = msg.content.map((part) => {
+          if ((part.type === "tool-call" || part.type === "tool-result") && "toolCallId" in part) {
+            return {
+              ...part,
+              toolCallId: part.toolCallId.replace(/[^a-zA-Z0-9_-]/g, "_"),
             }
-            return part
-          })
-        }
-        return msg
-      })
-    }
-    if (providerID === "mistral" || modelID.toLowerCase().includes("mistral")) {
-      const result: ModelMessage[] = []
-      for (let i = 0; i < msgs.length; i++) {
-        const msg = msgs[i]
-        const prevMsg = msgs[i - 1]
-        const nextMsg = msgs[i + 1]
-
-        if ((msg.role === "assistant" || msg.role === "tool") && Array.isArray(msg.content)) {
-          msg.content = msg.content.map((part) => {
-            if (
-              (part.type === "tool-call" || part.type === "tool-result") &&
-              "toolCallId" in part
-            ) {
-              // Mistral requires alphanumeric tool call IDs with exactly 9 characters
-              const normalizedId = part.toolCallId
-                .replace(/[^a-zA-Z0-9]/g, "") // Remove non-alphanumeric characters
-                .substring(0, 9) // Take first 9 characters
-                .padEnd(9, "0") // Pad with zeros if less than 9 characters
-
-              return {
-                ...part,
-                toolCallId: normalizedId,
-              }
-            }
-            return part
-          })
-        }
-
-        result.push(msg)
-
-        // Fix message sequence: tool messages cannot be followed by user messages
-        if (msg.role === "tool" && nextMsg?.role === "user") {
-          result.push({
-            role: "assistant",
-            content: [
-              {
-                type: "text",
-                text: "Done.",
-              },
-            ],
-          })
-        }
+          }
+          return part
+        })
       }
-      return result
-    }
-
-    return msgs
+      return msg
+    })
   }
 
   function applyCaching(msgs: ModelMessage[], providerID: string): ModelMessage[] {
@@ -120,7 +64,9 @@ export namespace ProviderTransform {
   }
 
   export function message(msgs: ModelMessage[], providerID: string, modelID: string) {
-    msgs = normalizeMessages(msgs, providerID, modelID)
+    if (modelID.includes("claude")) {
+      msgs = normalizeToolCallIds(msgs)
+    }
     if (providerID === "anthropic" || modelID.includes("anthropic") || modelID.includes("claude")) {
       msgs = applyCaching(msgs, providerID)
     }
@@ -151,12 +97,12 @@ export namespace ProviderTransform {
     }
 
     if (modelID.includes("gpt-5") && !modelID.includes("gpt-5-chat")) {
-      if (!modelID.includes("codex") && !modelID.includes("gpt-5-pro")) {
-        result["reasoningEffort"] = "medium"
+      if (modelID.includes("codex")) {
+        result["store"] = false
       }
 
-      if (providerID !== "azure") {
-        result["textVerbosity"] = modelID.includes("codex") ? "medium" : "low"
+      if (!modelID.includes("codex") && !modelID.includes("gpt-5-pro")) {
+        result["reasoningEffort"] = "medium"
       }
 
       if (providerID === "opencode") {