Antigravity and 9Router: choose the right connection

Antigravity is not one interchangeable API client. Its IDE, CLI, and SDK have different configuration paths. 9Router also lists Antigravity-related provider and integration capabilities. Before changing credentials, identify whether you want Antigravity to call a gateway or want a supported account connection to supply a model to another client.

Those are opposite directions. A successful provider login in 9Router does not demonstrate that every Antigravity product can call the local router.

Choose the direction of the connection

Your goal	What to verify
Use Antigravity’s own app or IDE	Supported models and account access in Google’s documentation
Change the CLI’s model endpoint	The CLI’s documented protocol and endpoint setting
Build with the Antigravity SDK	The SDK configuration class and server API compatibility
Use a supported Antigravity provider connection in 9Router	The router version, supported login method, and account eligibility

Do not copy an OpenAI-compatible base URL into a field that expects a Gemini-compatible service. The shared word “endpoint” does not make the protocols equivalent.

Antigravity CLI: use its documented configuration

Google’s CLI authentication documentation describes a Gemini API-key mode and a custom Gemini-compatible endpoint through GOOGLE_GEMINI_BASE_URL. That is not a general promise that an arbitrary /v1/chat/completions server will work.

Before pointing it at 9Router, verify that your router version exposes the required protocol and path for that integration. Keep a copy of the previous CLI settings and test in a separate shell. If authentication works but inference fails, inspect the first request and its endpoint rather than rotating unrelated credentials.

Follow Google’s current restore instructions to return to account-based authentication. Leaving an API-key mode selected while removing its required key can prevent the CLI from starting normally.

Antigravity SDK: a separate integration path

Google documents LocalOpenAIAgentConfig for connecting its Python SDK to an external local OpenAI-compatible model server. This is an SDK capability, not an IDE preferences switch. It can be relevant when you are building an application and control the code that constructs the agent.

Check the SDK’s current configuration parameters and the server’s supported API behavior before trying a gateway. Start with a short request and then a harmless tool call. A model server supporting basic chat may still differ in tool behavior or streaming details.

A provider connection inside 9Router

When your intention is to use a provider through 9Router, follow the connection flow present in your installed router version. Check which credentials it accepts, where authentication occurs, and which models the connection exposes. Use your own eligible account and review its current permitted usage.

After connecting, inspect the router model list and make a minimal request from a known working client. Keep the selected route explicit while testing. A provider entry or successful OAuth callback alone does not prove access to a specific model.

Treat IDE interception as a distinct setup

The 9Router project describes an IDE bridge for some integrations. Such a bridge is materially different from setting a documented API base URL: it can involve local proxying, certificates, or application-specific behavior. Review the current upstream instructions and restoration steps before enabling it.

This Wiki does not supply a blanket certificate-install command or claim that a bridge is supported by Google. Prefer a documented endpoint configuration when it meets your goal. If you evaluate a bridge, keep it isolated and ensure you understand how to return the IDE and trust settings to their prior state.

Check model access separately from configuration

Google’s available models and quotas depend on product and account plan. A local gateway does not expand that entitlement. When a model disappears or a request is rejected, check the current model availability documentation and your account before assuming the local address is wrong.

For a connection error, follow the proxy checks. If you only need a coding client with a straightforward gateway configuration, compare the documented Claude Code and OpenCode paths with the exact Antigravity product you intend to use.