fix: bump antigravity User-Agent header version (#2901)

resolves #2815

Co-authored-by: Mario Zechner <badlogicgames@gmail.com>

packages/ai/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- Bumped default Antigravity User-Agent version to `1.21.9` ([#2901](https://github.com/badlogic/pi-mono/pull/2901) by [@aadishv](https://github.com/aadishv))
 - Fixed thinking levels for Gemma 4 models to use `thinkingLevel` and map Pi reasoning levels to the model's supported thinking levels ([#2903](https://github.com/badlogic/pi-mono/pull/2903) by [@aadishv](https://github.com/aadishv))
 
 ## [0.66.1] - 2026-04-08

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

@@ -77,7 +77,7 @@ const GEMINI_CLI_HEADERS = {
 };
 
 // Headers for Antigravity (sandbox endpoint) - requires specific User-Agent
-const DEFAULT_ANTIGRAVITY_VERSION = "1.18.4";
+const DEFAULT_ANTIGRAVITY_VERSION = "1.21.9";
 
 function getAntigravityHeaders() {
 	const version = process.env.PI_AI_ANTIGRAVITY_VERSION || DEFAULT_ANTIGRAVITY_VERSION;

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Updated `antigravity-image-gen.ts` example extension to use User-Agent version `1.21.9` ([#2901](https://github.com/badlogic/pi-mono/pull/2901) by [@aadishv](https://github.com/aadishv))
 ### Added
 
 - Set `PI_CODING_AGENT=true` environment variable at startup so sub-processes can detect they are running inside the coding agent ([#2868](https://github.com/badlogic/pi-mono/issues/2868))

packages/coding-agent/examples/extensions/antigravity-image-gen.ts

@@ -48,7 +48,7 @@ type SaveMode = (typeof SAVE_MODES)[number];
 
 const ANTIGRAVITY_ENDPOINT = "https://daily-cloudcode-pa.sandbox.googleapis.com";
 
-const DEFAULT_ANTIGRAVITY_VERSION = "1.18.3";
+const DEFAULT_ANTIGRAVITY_VERSION = "1.21.9";
 
 const ANTIGRAVITY_HEADERS = {
 	"User-Agent": `antigravity/${process.env.PI_AI_ANTIGRAVITY_VERSION || DEFAULT_ANTIGRAVITY_VERSION} darwin/arm64`,