fix(ai): antigravity endpoint cascade on 403/404, add autopush fallback, strip extra headers

closes #1830

packages/ai/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Preserved OpenAI Responses assistant `phase` metadata (`commentary`, `final_answer`) across turns by encoding `id` and `phase` in `textSignature` for session persistence and replay, with backward compatibility for legacy plain signatures ([#1819](https://github.com/badlogic/pi-mono/issues/1819)).
+- Fixed Antigravity endpoint fallback: 403/404 responses now cascade to the next endpoint instead of throwing immediately, added `autopush-cloudcode-pa.sandbox` endpoint to the fallback list, and removed extra fingerprint headers (`X-Goog-Api-Client`, `Client-Metadata`) from Antigravity requests ([#1830](https://github.com/badlogic/pi-mono/issues/1830)).
 
 ## [0.56.1] - 2026-03-05
 

packages/ai/src/providers/google-gemini-cli.ts

@@ -59,7 +59,12 @@ export interface GoogleGeminiCliOptions extends StreamOptions {
 
 const DEFAULT_ENDPOINT = "https://cloudcode-pa.googleapis.com";
 const ANTIGRAVITY_DAILY_ENDPOINT = "https://daily-cloudcode-pa.sandbox.googleapis.com";
-const ANTIGRAVITY_ENDPOINT_FALLBACKS = [ANTIGRAVITY_DAILY_ENDPOINT, DEFAULT_ENDPOINT] as const;
+const ANTIGRAVITY_AUTOPUSH_ENDPOINT = "https://autopush-cloudcode-pa.sandbox.googleapis.com";
+const ANTIGRAVITY_ENDPOINT_FALLBACKS = [
+	ANTIGRAVITY_DAILY_ENDPOINT,
+	ANTIGRAVITY_AUTOPUSH_ENDPOINT,
+	DEFAULT_ENDPOINT,
+] as const;
 // Headers for Gemini CLI (prod endpoint)
 const GEMINI_CLI_HEADERS = {
 	"User-Agent": "google-cloud-sdk vscode_cloudshelleditor/0.1",
@@ -78,12 +83,6 @@ function getAntigravityHeaders() {
 	const version = process.env.PI_AI_ANTIGRAVITY_VERSION || DEFAULT_ANTIGRAVITY_VERSION;
 	return {
 		"User-Agent": `antigravity/${version} darwin/arm64`,
-		"X-Goog-Api-Client": "google-cloud-sdk vscode_cloudshelleditor/0.1",
-		"Client-Metadata": JSON.stringify({
-			ideType: "IDE_UNSPECIFIED",
-			platform: "PLATFORM_UNSPECIFIED",
-			pluginType: "GEMINI",
-		}),
 	};
 }
 
@@ -385,10 +384,13 @@ export const streamGoogleGeminiCli: StreamFunction<"google-gemini-cli", GoogleGe
 			};
 			const requestBodyJson = JSON.stringify(requestBody);
 
-			// Fetch with retry logic for rate limits and transient errors
+			// Fetch with retry logic for rate limits, transient errors, and endpoint fallbacks.
+			// On 403/404, immediately try the next endpoint (no delay).
+			// On 429/5xx, retry with backoff on the same or next endpoint.
 			let response: Response | undefined;
 			let lastError: Error | undefined;
 			let requestUrl: string | undefined;
+			let endpointIndex = 0;
 
 			for (let attempt = 0; attempt <= MAX_RETRIES; attempt++) {
 				if (options?.signal?.aborted) {
@@ -396,7 +398,7 @@ export const streamGoogleGeminiCli: StreamFunction<"google-gemini-cli", GoogleGe
 				}
 
 				try {
-					const endpoint = endpoints[Math.min(attempt, endpoints.length - 1)];
+					const endpoint = endpoints[endpointIndex];
 					requestUrl = `${endpoint}/v1internal:streamGenerateContent?alt=sse`;
 					response = await fetch(requestUrl, {
 						method: "POST",
@@ -411,8 +413,19 @@ export const streamGoogleGeminiCli: StreamFunction<"google-gemini-cli", GoogleGe
 
 					const errorText = await response.text();
 
-					// Check if retryable
+					// On 403/404, cascade to the next endpoint immediately (no delay)
+					if ((response.status === 403 || response.status === 404) && endpointIndex < endpoints.length - 1) {
+						endpointIndex++;
+						continue;
+					}
+
+					// Check if retryable (429, 5xx, network patterns)
 					if (attempt < MAX_RETRIES && isRetryableError(response.status, errorText)) {
+						// Advance endpoint if possible
+						if (endpointIndex < endpoints.length - 1) {
+							endpointIndex++;
+						}
+
 						// Use server-provided delay or exponential backoff
 						const serverDelay = extractRetryDelay(errorText, response);
 						const delayMs = serverDelay ?? BASE_DELAY_MS * 2 ** attempt;

packages/coding-agent/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fixed GPT-5.3 Codex follow-up turns dropping OpenAI Responses assistant `phase` metadata by preserving replayable signatures in session history and forwarding `phase` back to the Responses API ([#1819](https://github.com/badlogic/pi-mono/issues/1819)).
+- Fixed Antigravity reliability: endpoint cascade on 403/404, added autopush sandbox fallback, removed extra fingerprint headers ([#1830](https://github.com/badlogic/pi-mono/issues/1830)).
 - Fixed editor/footer visibility drift during terminal resize by forcing full redraws when terminal width or height changes ([#1844](https://github.com/badlogic/pi-mono/pull/1844) by [@ghoulr](https://github.com/ghoulr)).
 - Fixed footer width truncation for wide Unicode text (session name, model, provider) to prevent TUI crashes from rendered lines exceeding terminal width ([#1833](https://github.com/badlogic/pi-mono/issues/1833)).