dsh-subscription-antigravity

Reuse a Google Antigravity subscription (Google AI Pro / Ultra) as model providers in DeepSeek Harness. Authorize one or more Google accounts once; the plugin provisions an antigravity model route with Gemini, Claude, and GPT-OSS models from Cloud Code Assist and serves them through a loopback OpenAI-compatible proxy.

Protocol shape follows the pi-antigravity reference implementation. Unofficial integration — not affiliated with or endorsed by Google. Use only with an account and services you are authorized to access.

Install

npx --yes github:shaomingbo/dsh-subscription-antigravity#v0.2.1

The no-argument installer adds the bundle to the web profile (fixed tag source, pnpm install --ignore-scripts, atomic manifest writes, rollback on dependency-install failure). It never stops or restarts DSH — when it finishes, restart DSH manually and hard-refresh the Web GUI.

Other commands:

npx --yes github:shaomingbo/dsh-subscription-antigravity#v0.2.1 status
npx --yes github:shaomingbo/dsh-subscription-antigravity#v0.2.1 uninstall

Options: --profile <name> (default web), --source <spec>, --help. Environment: DSH_ANTIGRAVITY_SOURCE overrides the package source.

Local development (link:)

npx --yes github:shaomingbo/dsh-subscription-antigravity#v0.2.1 install \
  --source link:/Users/you/open-source/dsh-subscription-antigravity

A link: source is for development only; switch back to the fixed tag for normal use.

Manual fallback

Edit ~/.dsh/profiles/web/package.json by hand: add "dsh-subscription-antigravity": "github:shaomingbo/dsh-subscription-antigravity#v0.2.1" to dependencies and "dsh-subscription-antigravity" to dsh.profile.bundles, then run pnpm install --ignore-scripts in the profile directory. Restart DSH and hard-refresh afterwards.

Accounts, quota, and switching

1. Open Settings → Antigravity and choose Add Google account. Google is asked to show its account chooser; OAuth uses PKCE and the callback server listens only on localhost:51121.
2. Repeat to build a local account pool. Each account card shows its email, active state, project, lowest known remaining quota, reset time, and an expandable runtime-model quota list.
3. Choose Use this account to switch immediately without another OAuth flow. In-flight requests stay on their original account; new requests use the active one.
4. Optional Automatically switch on exhausted quota is off by default. When enabled it rotates only after an explicit quota-exhausted 429; ordinary rate limits, auth errors, network failures, and 5xx responses never trigger it.

A newly added account becomes active. Removing one deletes only that local credential; removing the active account selects the next saved account. The single antigravity entry in the DSH model picker always uses the active account. Existing v1 single-account files migrate automatically without a new sign-in.

For a remote/headless browser, paste the full callback URL (http://localhost:51121/oauth-callback?…) into the field provided. Requested Google scopes: aicode, cloud-platform, userinfo.email, userinfo.profile, cclog, experimentsandconfigs; review them before approving.

Models

Public model ids mirror the Antigravity CLI catalog; each exposes only the thinking levels the backend advertises (thinking effort maps to the backend's runtime ids — see SPEC.md):

Model	Input	Thinking
gemini-3.7-flash	text, image	low / medium / high
gemini-3.6-flash	text, image	low / medium / high
gemini-3.5-flash	text, image	low / medium / high
gemini-3.1-pro	text, image	low / high
claude-sonnet-4-6	text, image	high
claude-opus-4-6	text, image	high
gpt-oss-120b	text	medium

Model availability, entitlement, and quota are account-dependent. Settings fetches quotaInfo separately for every saved account; these are best-effort runtime-model snapshots, not a promise that different models share one pool.

How it works

flowchart LR
    A["llm-pi-ai Antigravity route"] --> B["Loopback proxy 127.0.0.1:51122"]
    B -->|streamGenerateContent| C["Cloud Code Assist daily endpoint"]
    D["Google OAuth PKCE"] --> E["Local account pool"]
    E --> F["Active account router"]
    F --> B

• The plugin provisions (and repairs) one route in llm-pi-ai.providers via the settings service — per-provider merge; your own edits to models are preserved, and other providers are never touched.
• The proxy binds 127.0.0.1 only and translates OpenAI chat completions (streaming SSE and JSON) into Cloud Code Assist envelopes, including tool calls, image inputs, thinking → reasoning_content, and quota-friendly error mapping. Override the port with DSH_ANTIGRAVITY_PROXY_PORT.
• Each generation request snapshots one account's token and project, so a manual switch cannot mix identities inside an in-flight request. Optional quota failover is serialized to avoid concurrent switch storms.
• The active access token syncs into the ordinary credentials seam (ANTIGRAVITY_ACCESS_TOKEN); an empty pool removes the seam value.
• Usage-based billing and non-Google endpoints are out of scope.

Credential safety

• OAuth tokens live only in the versioned account pool at $DSH_HOME/.antigravity-auth.json (0600, atomic writes). They are never sent to the browser RPC, logged, or exported, and go only to Google's OAuth and Cloud Code Assist endpoints. Upstream error text is redacted and bounded.
• Uninstall keeps the credential file. Delete $DSH_HOME/.antigravity-auth.json yourself for a full wipe.
• The installer only edits the profile package.json (dependency + bundle entry); it never reads credentials, never runs lifecycle scripts, and never stops/restarts DSH.

Development

npm install          # test-only tooling; the plugin itself has zero runtime deps
npm run check        # syntax checks + full test suite
npm test

The test suite covers the installer contract (temporary DSH_HOME installs, repeats, status, uninstall, malformed manifests, argument errors, rollback), v1→v2 credential migration, multi-account OAuth and refresh isolation, quota-only failover concurrency, the translation layer, loopback proxy, route provisioning, credential sync, per-account usage, locale parity, and pack contents.

License

MIT — see LICENSE. Protocol references: SPEC.md.