diff --git a/dist/providers/google-gemini-cli.js b/dist/providers/google-gemini-cli.js
index 3741764906f41e87eda9259f567b1d5332551a63..41fc6a92fc4c1f6f503b92320248391013badfb0 100644
--- a/dist/providers/google-gemini-cli.js
+++ b/dist/providers/google-gemini-cli.js
@@ -22,7 +22,7 @@ const GEMINI_CLI_HEADERS = {
 };
 // Headers for Antigravity (sandbox endpoint) - requires specific User-Agent
 const ANTIGRAVITY_HEADERS = {
-    "User-Agent": "antigravity/1.11.5 darwin/arm64",
+    "User-Agent": "antigravity/1.15.8 darwin/arm64",
     "X-Goog-Api-Client": "google-cloud-sdk vscode_cloudshelleditor/0.1",
     "Client-Metadata": JSON.stringify({
         ideType: "IDE_UNSPECIFIED",
diff --git a/dist/providers/openai-responses.js b/dist/providers/openai-responses.js
index bbfb29a68dc4dd9af141d705eaf5aad18d508d84..2ecea368779e3097c9370a806df16eca39acdee0 100644
--- a/dist/providers/openai-responses.js
+++ b/dist/providers/openai-responses.js
@@ -319,9 +319,11 @@ function buildParams(model, context, options) {
         model: model.id,
         input: messages,
         stream: true,
+        // Add instructions field for third-party Responses API compatibility
+        instructions: context.systemPrompt || "",
         prompt_cache_key: options?.sessionId,
     };
-    if (options?.maxTokens) {
+    if (options?.maxTokens && !model.compat?.stripMaxOutputTokens) {
         params.max_output_tokens = options?.maxTokens;
     }
     if (options?.temperature !== undefined) {