Free & Open-Weight Models in Antigravity: What to Run When Your Tokens Run Out

The Question: What Runs After the Tokens Are Gone

Short answer: Antigravity has no native way to run a free or open-weight model. It is Gemini-only, with no custom-model or API-key setting in the app. So once your included tokens run out, you have three honest options, ranked by how painless they are. One, stay on Gemini and get ruthless about token economy (the 3.1 Pro versus 3.5 Flash decision below). Two, bring your own open-weight model through a community proxy and accept that it is a preview-only, grey-area workaround. Three, do your open-weight work in a tool that supports bring-your-own-key directly, such as Claude Code, Cursor, or OpenCode, and keep Antigravity for what it does best.

If you just want the fastest fix, the community consensus is clear: wire in GLM-5.2 when quality matters, DeepSeek V4-Flash when cost is everything, and run Qwen3.6-27B locally when your code cannot leave the building. Everything after this is the detail that keeps you from wasting a weekend or leaking a codebase. If your specific problem is Opus or Gemini quota running dry mid-task, the fallback workflow for when Antigravity runs out of tokens is the companion piece to this one.

The Models Worth Wiring In

Open weights moved fast in mid-2026, and a handful of models are now genuinely worth the setup friction. The table is deliberately short: these are the ones Antigravity users actually reach for, with the honest strengths and the cheapest way to get to each one. Prices are per million tokens and vary by host.

The pattern to internalize: GLM-5.2 is the one that plans, DeepSeek V4-Flash is the one that implements cheaply, and Qwen3.6-27B is the one you own outright. MiMo and MiniMax are worth knowing about for near-free experimentation, but the Freebuff and OpenCode limits behind them are community claims, not published SLAs, so do not build a workflow that assumes they will still be unlimited next month.

The BYOK Reality: Antigravity Is Gemini-Only

Here is the part the marketing skips. Antigravity 2.0 ships with no custom-model configuration and no API-key field. Multiple threads on the Google AI Developer Forum confirm it, and the desktop model picker only offers Gemini tiers. So every open-weight route into Antigravity is a workaround, and the main one is a proxy that pretends to be Google.

The forward bridge is antigravity-proxy (MIT, roughly 400 lines of TypeScript). It intercepts Antigravity's outbound HTTPS on port 443, translates the Gemini request format into an OpenAI-compatible call, and forwards it to a provider like NVIDIA NIM or OpenRouter, translating messages, tools, streaming, and even the safety and grounding metadata back. Setup is one PowerShell script and your API key. It has been tested with DeepSeek V4-Flash; only audio and background sync still need real Gemini.

# Forward: reach non-Gemini models FROM Antigravity (antigravity-proxy, MIT)
Antigravity  ->  HTTPS :443  ->  antigravity-proxy  ->  OpenAI-compatible API
                                                        (NVIDIA NIM / OpenRouter)

# Setup is one PowerShell script + your API key.
# Tested with deepseek-v4-flash. Only audio + background sync still need Gemini.
# github.com/12errh/antigravity-proxy

There is also a reverse move that a lot of people actually prefer: antigravity-claude-proxy. Instead of pulling open models into Antigravity, it exposes Antigravity's own Claude and Gemini models behind an Anthropic-compatible API, so you can drive them from Claude Code. It is free during the public preview, including the thinking modes, subject to the daily quota. The author frames it plainly as a learning aid, not a commercial dependency.

# Reverse: use Antigravity's models INSIDE Claude Code (preview-only)
npm install -g antigravity-claude-proxy
antigravity-claude-proxy accounts add    # optional load balancing
antigravity-claude-proxy start

# Claude Code settings.json:
"ANTHROPIC_BASE_URL": "http://localhost:8080"

# then just run
claude

Be clear-eyed about both tools. They depend on preview behavior and sit in a terms-of-service grey area — Google can change the wire format or tighten the preview at any time, and nothing here is a supported product. If you want a durable, first-class BYOK setup, honestly it is easier to do that work in a tool built for it. Our Antigravity vs Claude Code comparison walks through where each one actually wins, and for local weights specifically the Antigravity local models via Ollama setup is the step-by-step.

The Google Cloud Credits Path (Read the Caveat)

The most-repeated free suggestion is not a model at all, it is a billing trick: sign up for Google Cloud's $300 in free credits over 90 days, create a project, enable the Vertex AI API under IAM, and then at the Antigravity login choose "sign in with a Cloud project" at the bottom of the screen. Your Gemini usage then draws down the credits instead of your included tokens.

The caveat is the whole story. A card is required, and at least one user hit a $30.00 prepayment screen rather than a clean free tier. More importantly, once the credits are gone this is pay-as-you-go: a Google employee confirmed the GCP project route is billed per use, and one user reported burning around $60 on a single trivial task (a sub-2,000-row CSV update). So the credits path is real and useful for 90 days, but it is not a permanent free tier — it is a metered account with a trial balance, and Gemini 3.1 Pro can spend that balance faster than you expect.

The 3.1 Pro vs 3.5 Flash Token Economy

Before you reach for any proxy, the cheapest win is often just picking the right Gemini tier. The definitive community thread on this pits 3.1 Pro (Low) against 3.5 Flash (Medium), and it is genuinely contested. The original poster found 3.1 Pro (Low) far kinder on token consumption for a minimal quality difference — a couple of hours in and still at 60% quota. Several high-voted replies agreed that 3.1 Pro both spends less and performs better.

The dissent matters too. One well-upvoted reply argues 3.5 Flash is both more expensive and better at coding, and that 3.1 Pro is cheaper but inferior — with the reminder that there is still no 3.5 Pro to split the difference. Another user cited an Arena graph showing 3.1 and 3.5 at similar smartness but with 3.5 as the number-one token spender, and a memorable line that Gemini's thinking can be self-destructive: the more it thinks, the more it spirals. A separate thread even claims older models feel dumber than they did at launch, blaming quantization — but that is unverified speculation, and at least one user reports no change since December, so treat it as folklore, not fact.

The practical read: default to 3.1 Pro (Low) for token economy, and only reach for 3.5 Flash on the specific coding tasks where you can feel the difference. If quota keeps evaporating, the deeper fixes live in our guide to handling Antigravity running out of tokens.

Quality and Privacy Caveats You Cannot Skip

The quality story is better than the skeptics expect. On r/ClaudeAI, a senior developer with three Claude Max subscriptions called GLM-5.2 the first non-Claude model that feels close to Opus, saying that with thinking set to max it seemed on par with Opus 4.8 at extra-high effort. The most striking anecdote: a nasty concurrency bug that Opus 4.8, GPT-5.5, and Flash 3.5 could not track for months, which GLM-5.2 reportedly figured out in under 20 minutes of low-level C. On r/codex, a post-nerf tester was blunter still: it felt like GPT-5.3 Codex when it was fresh.

Now the part that should govern your setup. On Chinese-hosted coding plans, your code may be training data. A widely upvoted r/codex comment reads Z.ai's terms as not making clear how your code is treated, and warns that on the Coding Plan they can likely consume your codebase and train on it. That is not a reason to avoid the model — it is a reason to control where it runs. For anything proprietary, use bring-your-own-key, self-host the open weights, or pick a US-hosted provider such as Ollama Cloud, DeepInfra, or NVIDIA NIM.

Two more caveats round it out. First, tool-calling gets flaky through unofficial base-URL overrides and proxies; a direct provider key is more reliable than a bent one. Second, local is not automatically cheap: GLM-5.2 and DeepSeek V4-Pro are hundreds of billions of parameters and need multi-GPU rigs even at 4-bit, so the realistic local model for most people is Qwen3.6-27B, not the frontier weights.

FAQ

Glossary

Verdict

If you have burned your included tokens, here is the opinionated ranking. When you can bring your own key, wire in GLM-5.2 — it is the one open-weight model that plans as well as it codes, and it is the closest thing to Opus outside Anthropic. When cost is the only constraint, DeepSeek V4-Flash is unbeatable per token. When privacy is non-negotiable, run Qwen3.6-27B locally or on a US host and never send the code offshore.

Inside Antigravity specifically, though, the honest answer is still Gemini. The proxies are clever and worth trying for a weekend, but they are preview-only and sit in a terms-of-service grey area — do not build a business on them. The durable win is boring: default to 3.1 Pro (Low) for token economy, keep the heavy open-weight work in Claude Code or Cursor where BYOK is first-class, and treat Antigravity as one surface in a multi-tool setup rather than the only one. If you are weighing that move, our best Antigravity alternatives for 2026 breakdown is the next stop.

Sources

This guide leans on community reporting (mostly r/google_antigravity and adjacent subreddits) plus the open-source project pages and pricing references. Model claims, proxy behavior, and free-tier limits are community-reported unless linked to a first-party page, and are labeled that way in the text above.

Community threads

• r/google_antigravity: What free models are you using after running out of included tokens?
• r/google_antigravity: 3.1 Pro (Low) vs 3.5 Flash (Medium), the token-economy thread
• r/google_antigravity: Are they making old models stupid on purpose?
• r/google_antigravity: Expensive with the GCP login route
• r/ClaudeAI: GLM 5.2 via Claude Code is the first non-Claude model that feels close to Opus
• r/codex: After the nerf I tried GLM 5.2 (includes the privacy caveat)
• r/cursor: GLM-5.2 is out on Cursor
• r/LocalLLaMA: GLM-5.2 is a win for local AI

Tools and proxies

• antigravity-proxy: forward TLS bridge to OpenAI-compatible models (MIT)
• antigravity-claude-proxy: reverse proxy exposing Antigravity models to Claude Code
• Syntackle: using Antigravity models in Claude Code via the reverse proxy

Model and pricing references

• Morph: SWE-bench Pro leaderboard (coding yardstick)
• Morph: DeepSeek V4 spec and pricing
• OpenRouter: GLM-5.2 pricing
• DeepSeek: official pricing docs

Social

• @cline: $9.99/mo pass for discounted GLM, DeepSeek, Kimi, and Qwen
• @ollama: GLM-5.2 on Ollama Cloud (US-hosted)
• @rauchg: shocked at how good GLM-5.2 is
• @Zai_org: GLM-5.2, frontier intelligence with open weights