fix(antigravity): resolve HTTP 400 toolConfig and HTTP 403 x-goog-user-project errors

open-sse/services/antigravityHeaderScrub.ts

@@ -41,6 +41,8 @@ const HEADERS_TO_REMOVE = [
   // Encoding: Antigravity (Node.js) sends "gzip, deflate, br" by default;
   // Electron clients add "zstd" which is a fingerprint mismatch.
   "accept-encoding",
+  // Google Cloud project header — Antigravity backend throws HTTP 403 when present
+  "x-goog-user-project",
 ];
 
 /**

tests/unit/antigravity-headers.test.ts

@@ -10,6 +10,7 @@ import {
   getAntigravityLoadCodeAssistMetadata,
   getAntigravityOAuthUserAgent,
 } from "../../open-sse/services/antigravityHeaders.ts";
+import { scrubProxyAndFingerprintHeaders } from "../../open-sse/services/antigravityHeaderScrub.ts";
 import {
   clearAntigravityVersionCaches,
   seedAntigravityCliVersionCache,
@@ -65,12 +66,23 @@ test("IDE and CLI content headers use independent cached versions", () => {
       "x-vscode-sessionid",
       "X-Goog-Api-Client",
       "Client-Metadata",
+      "x-goog-user-project",
     ]) {
       assert.equal(headers.get(absent), null, `${absent} must be absent from content headers`);
     }
   }
 });
 
+test("scrubProxyAndFingerprintHeaders strips x-goog-user-project header", () => {
+  const input = {
+    "Content-Type": "application/json",
+    "x-goog-user-project": "my-project-123",
+    Authorization: "Bearer token",
+  };
+  const scrubbed = scrubProxyAndFingerprintHeaders(input);
+  assert.equal(scrubbed["x-goog-user-project"], undefined);
+});
+
 test("IDE Node OAuth and onboarding headers use the captured Google Node identity", () => {
   seedAntigravityIdeVersionCache("2.1.1");
   const headers = new Headers(getAntigravityIdeNodeHeaders("token"));

tests/unit/antigravity-tool-config.test.ts

@@ -0,0 +1,28 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { antigravityToOpenAIRequest } from "../../open-sse/translator/request/antigravity-to-openai.ts";
+
+test("antigravityToOpenAIRequest strips toolConfig from translated tools", () => {
+  const body = {
+    request: {
+      contents: [{ role: "user", parts: [{ text: "Hello" }] }],
+      tools: [
+        {
+          functionDeclarations: [
+            {
+              name: "get_weather",
+              description: "Get weather",
+              parameters: { type: "OBJECT", properties: { location: { type: "STRING" } } }
+            }
+          ]
+        }
+      ],
+      toolConfig: { functionCallingConfig: { mode: "VALIDATED" } }
+    }
+  };
+
+  const res = antigravityToOpenAIRequest("gemini-2.5-flash", body, false);
+  assert.equal(res.toolConfig, undefined);
+  assert.equal(Array.isArray(res.tools), true);
+  assert.equal(res.tools?.length, 1);
+});