According to @auricxofficial, a code diff of an Antigravity 2.0 Insiders build shows a context-window selector for Gemini 4 Argon, with 256K, 512K and 900K options. Google hasn’t announced these context-window options.

What it shows

The post compares two builds, referred to as main.js and main.now.js. In the newer build, a separate “Context window” list appears only when the base model is Gemini 4 Argon. Other models keep the generic effort menu. The post says the 256K option is the default. It labels 512K as using “about 1.3x quota per turn” and 900K as using “about 1.8x quota per turn,” and both larger options carry an "Expensive" badge.

Screenshot of code excerpts from main.now.js showing Gemini 4 Argon context-window options and quota multiplier labels.
Screenshot of code excerpts from main.now.js showing Gemini 4 Argon context-window options and quota multiplier labels.

Image credit: @auricxofficial on X

The post's second image compares the two files. Its table gives the newer build as 147,075 bytes larger (+1.48%), shows no hits for the Gemini 4 Argon string in the older build and one in the newer, and lists a new ChatModelMetadata protobuf message with several field changes. The post notes that raw line diffs are noisy, so it compares extracted identifiers, constants and text instead.

Table comparing old and new Antigravity build metrics, including byte and line counts and one Gemini 4 Argon string hit.
Table comparing old and new Antigravity build metrics, including byte and line counts and one Gemini 4 Argon string hit.

Image credit: @auricxofficial on X

What it could mean

The model itself is not a rumour: Google has announced Gemini 4 Argon, as described in our coverage of the announcement. That announcement says the model is first rolling out to trusted testers through the Fairwind Program, with broader access for paid API customers and Google AI Ultra subscribers afterward, and gives no launch date for either route; its 1 million output-token limit is a separate figure for a single extended run. If the options are real, they would add a per-turn quota cost for long context inside Antigravity, a separate meter from the API token pricing developers pay. Our earlier coverage of Gemini 4 Argon variants reported as Barium-B and a Google Cloud listing belongs to the same leak family.

Status: unconfirmed. We'll update this page when Google confirms or denies it.

Sources