dsh-gemini-oauth-bridge

If you already pay for a Google AI Pro or AI Ultra subscription but wish you had a clean Gemini model slot inside DeepSeek Harness, this plugin was built for exactly that. It emulates the Antigravity client OAuth login and request surface, bridging your subscription quota into a standard OpenAI-compatible endpoint (streaming SSE and non-streaming chat/completions, plus v1/models discovery) so DSH can call Gemini models without a separate API-credit purchase.

Under the hood the bridge performs full bidirectional protocol translation: system messages, data-URL multimodal images, tool_calls mapped to functionCall and functionResponse, reasoning_content thinking streams, usage statistics, and finish-reason mapping all work out of the box. For Gemini 3 multi-turn tool calls that require thought-signature replay, a field the OpenAI format simply does not carry, the plugin caches signatures by tool-call id and re-attaches them on the next turn, preventing the silent failures that would otherwise occur. Subscription-friendly extras include a live version tracker that fetches the newest Antigravity build every six hours to satisfy upstream UA checks, per-model 429 cooldown windows driven by Retry-After or retryDelay, and single-flight token refresh so concurrent requests share one renewal.

It is aimed at individual AI Pro or Ultra subscribers who want zero-marginal-cost Gemini multimodal and function-calling capability inside a DSH workflow. A few caveats: this is an unofficial integration relying on public OAuth credentials and a non-public internal API surface, so Google can change or block it at any time and account risk is non-trivial. Current limitations include single-account use, data-URL-only image input, a fixed loopback callback port 51121 that can clash with the Antigravity desktop app, and an LRU signature cache capped at 800 entries. Evaluate the trade-offs before adopting.