Antigravity: model picker only offers Gemini 3.8 Flash (Low); thinking-level variants (Medium/High) not selectable

[Mchicao]

Environment

Windows 11 x64, T3 Code Nightly 0.0.39-nightly.20260903.1272, Antigravity provider signed in with a Google account (sign-in working after the #9405/#9425 saga).

Symptom

In the Antigravity model picker, the only current model entry is Gemini 3.8 Flash (Low). The other thinking levels of 3.8 Flash are not selectable anywhere: there is no separate thinking/effort selector (the level is embedded in the model name), and the picker only offers a collapsed "Legacy models — 2 models" group next to the single (Low) entry. Screenshot can be attached on request.

What the agent actually returns

Driving agy_acp_server directly (initialize → authenticate → session/new), the model config option returns 11 entries, including all three 3.8 effort variants with IDs that match the manifest exactly:

• gemini-3.8-flash-high — "Gemini 3.8 Flash (High)"
• gemini-3.8-flash-medium — "Gemini 3.8 Flash (Medium)"
• gemini-3.8-flash-low — "Gemini 3.8 Flash (Low)"
• gemini-3.7-flash-{high,medium,low}
• gemini-3.6-flash-{high,medium,low}
• gemini-pro-agent — "Gemini 3.1 Pro (High)"
• gemini-3.1-pro-low — "Gemini 3.1 Pro (Low)"

A fresh session/new also comes back with currentValue: gemini-3.7-flash-high.

Expected

model-manifest.json as shipped in 1272 marks the three 3.8 slugs as current for antigravity and sets defaults.chat = gemini-3.8-flash-high, so the picker should offer High/Medium/Low as current models. The agent data supports it, so something in the model snapshot/classification or in the picker is dropping the other two variants (or folding them into the legacy group).

Steps to reproduce

1. Sign in to the Antigravity provider with a Google account.
2. Open a chat and open the model picker.
3. Only "Gemini 3.8 Flash (Low)" shows as a current model; the thinking level cannot be changed.

[t3dotgg]

Note

🤖 GPT-6 Astra (preview) responding on behalf of Theo

I tested the merged Antigravity changes with a native-format fixture that returns these 11 model IDs and gemini-3.7-flash-high as the initial selection. The picker showed all three 3.8 levels as current models and eight legacy models. I could not reproduce the Low-only list.

PR #9511 fixes live catalog updates, but this does not prove that it fixes this report. A signed-in Windows runtime still needs verification, so I am leaving this issue open.