Antigravity vs Claude Code (2026): you can run Opus 4.6 in both (field log)

Quick answer

In 2026, "Antigravity vs Claude Code" is a category error, and I only worked that out by opening Google's own model docs. Antigravity lets you select Claude. Its published model table lists Claude Sonnet 4.6 (thinking) and Claude Opus 4.6 (thinking) as available on the free tier, on Google AI Pro and on Google AI Ultra (Antigravity models, 2026). So the model is not the variable. You can point both tools at the same Opus 4.6 and get the same weights.

What differs is the harness: what the agent is allowed to touch, how many of them run at once, and who checks the work. That is the comparison worth making, and page one is not making it.

The thing page one gets wrong

Read the search results for this query and you get seven variations of one sentence: Antigravity is the parallel visual one, Claude Code is the careful terminal one. Google's own AI Overview says it too, almost word for word.

It is not wrong exactly. It is just describing the packaging and calling it the product. The top organic result is a Reddit thread where someone writes that they "tested opus 4.6 on Claude code and Opus 4.6 with Antigravity it was day and night." They meant it as a verdict on Antigravity. Read it again: they held the model constant and got two different outcomes. That is a statement about harnesses, and it is the most useful sentence on the entire SERP.

Nobody follows it anywhere. Every ranking write-up I checked, including the most thorough one at Codegen, treats the two as mutually exclusive purchases. None of them mention that Antigravity offers Claude, and none of them discuss running both.

What I actually did here

Not a week-long bake-off. I want to be straight about that, the same way I was in the Devin field log: I sat down with both vendors' documentation open side by side and checked the claims this SERP repeats. Two of them did not survive.

The first is the model claim, above. The second is subtler and I have not seen it written down anywhere.

The Enterprise gotcha nobody mentions

Antigravity's model availability table has four plan columns, and the Claude rows are not uniform across them. Claude Sonnet 4.6 and Claude Opus 4.6 are marked available on Free and Google AI Plus, on Google AI Pro, and on Google AI Ultra. On Enterprise they are marked unavailable, along with GPT-OSS-120b (Antigravity models, 2026).

Enterprise gets Gemini. Only Gemini.

Sit with that for a second, because it inverts the usual shape of these things. The hobbyist on the free tier can pick Opus 4.6. The company paying for Enterprise cannot. If you are the person who evaluated Antigravity on your personal account, loved how it handled a refactor with Claude driving, and then rolled it out to a team on Enterprise, you have shipped your colleagues a different product than the one you tested. That is a genuinely expensive misunderstanding and it is one table cell deep in the docs.

The quota behaviour differs by tier too: Google AI Pro and AI Ultra quotas refresh every five hours until a weekly limit, while everyone else gets a weekly refresh (Antigravity plans, 2026). Free is real, but free is a bucket.

So what is actually different

Once you take the model out of the equation, three differences are left, and they are all about control surface.

Where the agent lives. Antigravity is four things: the 2.0 command center, an IDE, a Python SDK, and a CLI that Google describes as "the lightweight, fast, terminal-first surface to work with Antigravity agents." Claude Code is one engine exposed through a terminal CLI, IDE extensions, a desktop app and the web, and Anthropic's docs are explicit that they share state: "your CLAUDE.md files, settings, and MCP servers work across all of them" (Claude Code overview, 2026).

That shared-state line is the practical difference. Move between Claude Code surfaces and your project instructions follow you. Move from Claude Code to Antigravity and they do not, because Antigravity has its own context conventions. Whatever you encoded in CLAUDE.md is house rules that only one house honours.

How many agents. Antigravity 2.0 is built to "manage multiple local agents in parallel" and adds browser-in-the-loop agents that drive a real browser to check runtime behaviour. Claude Code has subagents and background agents. Both do parallelism. The difference is that Antigravity puts the fan-out in a GUI you watch, and Claude Code puts it behind a prompt you supervise.

Who checks the work. This is the one that matters and it is where the two genuinely diverge. Antigravity's answer is artifacts: the agent produces a plan, a walkthrough, screenshots, browser recordings, and you review the evidence after the fact. Claude Code's answer is consent before the fact, plus hooks that fire shell commands around every action, plus whatever your test suite already does.

Reviewing evidence after the fact is faster and it scales to more concurrent agents. Approving actions before the fact is slower and catches the thing that would have been annoying to undo. Neither is correct. I use them for different sizes of change, and after a year of this I have stopped pretending that preference is a technical argument.

Running both on one repo

Since Antigravity's CLI is terminal-first and Claude Code runs in any terminal, there is nothing stopping you opening both against the same project. People do. It is also the fastest way I know to corrupt an afternoon.

The problem is not the tools. It is that a git working tree is a single mutable thing and you have pointed two autonomous writers at it. Agent A reads a file, thinks for forty seconds, and writes back a version that silently reverts three edits agent B made in between. Nothing errors. Your tests may even pass, because both edits were individually fine. You find it two commits later.

The fix is the same one I landed on for running multiple coding agents in parallel with git worktrees: give each agent its own worktree, its own branch, and let git's merge machinery be the thing that resolves conflicts, because that is the one piece of this stack actually designed to. One repo, two checkouts, two agents, no races.

With that in place the useful split is obvious rather than clever. Claude Code in a worktree for the change you would be annoyed to redo, where you want the permission prompt. Antigravity for the fan-out work where you would rather review artifacts than approve steps. Same Opus 4.6 underneath if you want it to be.

Where each one loses

Antigravity loses on portability. Your instructions, hooks and skills are Antigravity's, not yours, and the Enterprise model gate means the configuration you validated may not be the configuration you deploy.

Claude Code loses on price and on eyes. There is no free tier: the docs say most surfaces require a Claude subscription or a Console account, against Antigravity's "available at no charge." And when you want to watch five things happen at once, a terminal is a bad dashboard. That is not a knock, it is just what a terminal is.

What I would tell someone choosing today

If you are picking one and you like terminals, the free tier makes this easy: install Antigravity, set the model to Claude Opus 4.6, and you have tested the model half of the question for nothing. If it is enough, you are done and you saved a subscription. If you find yourself missing the permission prompt, the CLAUDE.md that follows you between surfaces, and the hook that runs your formatter on every edit, that is Claude Code you are missing, not Claude.

And if you are evaluating for a team on Enterprise, run your evaluation on Enterprise. Check the model picker before you check anything else.