diff --git a/backend/src/utils/llm/providers.ts b/backend/src/utils/llm/providers.ts
index f14039a..f39bc37 100644
--- a/backend/src/utils/llm/providers.ts
+++ b/backend/src/utils/llm/providers.ts
@@ -351,7 +351,7 @@ function maskSecret(s: string | undefined): string {
   return s.slice(0, 6) + "…" + s.slice(-4);
 }
 
-const FIXED_TEMPERATURE_MODELS = new Set(["gpt-5-nano"]);
+const FIXED_TEMPERATURE_MODELS = new Set(["gpt-5-nano", "claude-opus-4-7", "claude-opus-4-8"]);
 
 function clampTemperature(model: string, requested: number): number {
   for (const m of FIXED_TEMPERATURE_MODELS) {
@@ -418,15 +418,17 @@ function logResponse(
 function buildCompletionConfig(
   config: ProviderConfig,
   opts: InvokeOptions & { abortSignal?: AbortSignal },
-  temperature: number,
+  temperature: number | undefined,
   stream: boolean,
 ): any {
   const params: any = {
     model: config.model,
     messages: opts.messages,
-    temperature,
     stream,
   };
+  if (temperature !== undefined) {
+    params.temperature = temperature;
+  }
 
   if (stream) {
     params.stream_options = { include_usage: true };
@@ -597,7 +599,7 @@ export async function invoke_llm(opts: InvokeOptions): Promise<InvokeResult> {
 
   const client = getClient(config, opts);
 
-  const tryCompletion = async (temp: number): Promise<InvokeResult> => {
+  const tryCompletion = async (temp: number | undefined): Promise<InvokeResult> => {
     const params = buildCompletionConfig(config, opts, temp, false);
     const response = (await client.chat.completions.create(
       params,
@@ -624,15 +626,18 @@ export async function invoke_llm(opts: InvokeOptions): Promise<InvokeResult> {
     return await tryCompletion(requestedTemp);
   } catch (err: any) {
     const isTempUnsupported =
-      err?.code === "unsupported_value" &&
+      (err?.code === "unsupported_value" &&
       err?.param === "temperature" &&
-      requestedTemp !== 1;
+      requestedTemp !== 1) ||
+      (err?.status === 400 &&
+      err?.message?.includes("temperature") &&
+      requestedTemp !== 1);
 
     if (isTempUnsupported) {
       console.warn(
         `[inference] Model ${config.model} does not support temperature=${requestedTemp}, retrying with temperature=1`,
       );
-      return await tryCompletion(1);
+      return await tryCompletion(undefined);
     }
 
     const elapsed = Date.now() - start;
@@ -1231,7 +1236,7 @@ export async function invoke_llm_streaming(
 
   logRequest(config, opts, true);
 
-  const runStream = async (temp: number): Promise<InvokeResult> => {
+  const runStream = async (temp: number | undefined): Promise<InvokeResult> => {
     const params = buildCompletionConfig(config, opts, temp, true);
 
     if (
@@ -1363,13 +1368,16 @@ export async function invoke_llm_streaming(
     return await runStream(requestedTemp);
   } catch (err: any) {
     const isTempUnsupported =
-      err?.code === "unsupported_value" &&
+      (err?.code === "unsupported_value" &&
       err?.param === "temperature" &&
-      requestedTemp !== 1;
+      requestedTemp !== 1) ||
+      (err?.status === 400 &&
+      err?.message?.includes("temperature") &&
+      requestedTemp !== 1);
 
     if (isTempUnsupported) {
       console.warn(`[inference] Retrying stream with temperature=1`);
-      return await runStream(1);
+      return await runStream(undefined);
     }
 
     const isToolsUnsupported =
diff --git a/backend/src/utils/modelRegistryStore.ts b/backend/src/utils/modelRegistryStore.ts
index 6458efb..5ba9435 100644
--- a/backend/src/utils/modelRegistryStore.ts
+++ b/backend/src/utils/modelRegistryStore.ts
@@ -302,7 +302,8 @@ function writeProfileRegistry(registry: ModelRegistry): void {
   const profilePath = getModelRegistryPath();
   fs.mkdirSync(path.dirname(profilePath), { recursive: true });
   fs.writeFileSync(`${profilePath}.tmp`, `${JSON.stringify(registry, null, 2)}\n`, "utf-8");
-  fs.renameSync(`${profilePath}.tmp`, profilePath);
+  fs.copyFileSync(`${profilePath}.tmp`, profilePath);
+  fs.unlinkSync(`${profilePath}.tmp`);
 }
 
 function registryFromEnvJson(env: Record<string, string>): ModelRegistry {