feat(opencode-v2): OpenCode 2.x host adapter (reuses the existing core)

.github/workflows/release.yml

@@ -79,6 +79,8 @@ jobs:
             workspace: "@cortexkit/opencode-antigravity-auth"
           - package: "@cortexkit/pi-antigravity-auth"
             workspace: "@cortexkit/pi-antigravity-auth"
+          - package: "@cortexkit/opencode-v2-antigravity-auth"
+            workspace: "@cortexkit/opencode-v2-antigravity-auth"
     steps:
       - uses: actions/checkout@v5
         with:

README.md

@@ -2,12 +2,13 @@
 
 Google Antigravity OAuth for coding agents. Authenticate with your Google account and access Antigravity quota for Gemini, Claude, and GPT-OSS models from OpenCode, the Pi coding agent, or the standalone CLI.
 
-This monorepo ships three packages:
+This monorepo ships four packages:
 
 | Package | Host | Role |
 | --- | --- | --- |
 | [`@cortexkit/opencode-antigravity-auth`](packages/opencode) | OpenCode 1.x server | Intercepts `fetch()`, runs the account pool + quota manager, drives slash commands, and exposes a TUI sidebar through a loopback RPC. |
 | [`@cortexkit/pi-antigravity-auth`](packages/pi) | Pi coding agent | Registers a custom provider with OAuth login + Gemini streaming. |
+| [`@cortexkit/opencode-v2-antigravity-auth`](packages/opencode-v2) | OpenCode 2.x server | Registers the Antigravity models through the native plugin API: a loopback bridge for the account pool and transport, an OAuth method that appends accounts, and a document tool for PDF input. |
 | [`@cortexkit/antigravity-auth-core`](packages/core) | Any harness | Harness-agnostic core: OAuth PKCE, raw HTTP/1.1 transport, device fingerprint, request transforms, account pool, quota manager, durable storage. Both host packages depend on it. |
 
 ## Risk and terms-of-service warning
@@ -404,14 +405,14 @@ The script enforces semver, refuses to run on a dirty tree, and refuses to run o
 The `Release` workflow (`.github/workflows/release.yml`) runs on tag push (or `workflow_dispatch`) and:
 
 1. **Test** job — checkout the tag ref → install Bun 1.3 + Node 24 → `bun install --frozen-lockfile` → `bun run typecheck` → `bun run build` → `bun run --cwd packages/opencode smoke:tui` → `bun test` → `bun run test:e2e` → `bun run format:check` → `bun run lint`.
-2. **Publish** job — matrixed across the three packages (`@cortexkit/antigravity-auth-core`, `@cortexkit/opencode-antigravity-auth`, `@cortexkit/pi-antigravity-auth`) with `max-parallel: 1` so each package picks up its own OIDC token; `npm Trusted Publishing` (`npm publish --workspace … --access public --provenance`) handles the upload. The job skips a package if its npm version is already published.
+2. **Publish** job — matrixed across the four packages (`@cortexkit/antigravity-auth-core`, `@cortexkit/opencode-antigravity-auth`, `@cortexkit/pi-antigravity-auth`, `@cortexkit/opencode-v2-antigravity-auth`) with `max-parallel: 1` so each package picks up its own OIDC token; `npm Trusted Publishing` (`npm publish --workspace … --access public --provenance`) handles the upload. The job skips a package if its npm version is already published.
 3. **GitHub Release** job — `softprops/action-gh-release@v2` creates the GitHub release with `generate_release_notes: true`.
 
 CI (`.github/workflows/ci.yml`) reuses the same typecheck → build → smoke → test → e2e → format → lint chain on every push to `main` and on every pull request. The `issue-triage.yml` workflow handles GitHub-issue routing.
 
 ## Architecture and structure links
 
-- [ARCHITECTURE.md](ARCHITECTURE.md) — system-of-record architecture doc across all three packages.
+- [ARCHITECTURE.md](ARCHITECTURE.md) — system-of-record architecture doc across all four packages.
 - [STRUCTURE.md](STRUCTURE.md) — file-system map of the monorepo.
 - [packages/opencode/ARCHITECTURE.md](packages/opencode/ARCHITECTURE.md) — OpenCode plugin architecture in detail.
 - [packages/opencode/STRUCTURE.md](packages/opencode/STRUCTURE.md) — OpenCode package file-system map.

biome.jsonc

@@ -24,6 +24,7 @@
       "packages/*/scripts/**",
       "scripts/**",
       "test/**",
+      "packages/*/test/**",
       "*.json",
       "packages/*/*.json",
       ".github/**/*.yml"

package.json

@@ -7,8 +7,8 @@
   ],
   "scripts": {
     "build": "bun run --cwd packages/core build && bun run --cwd packages/opencode build && bun run --cwd packages/pi build",
-    "typecheck": "bun run --cwd packages/core build && bun run --cwd packages/opencode typecheck && bun run --cwd packages/pi typecheck && tsc -p tsconfig.scripts.json",
-    "test": "bun run --cwd packages/core build && bun test --isolate packages/core/src packages/opencode/src packages/pi/src test/",
+    "typecheck": "bun run --cwd packages/core build && bun run --cwd packages/opencode typecheck && bun run --cwd packages/pi typecheck && tsc -p tsconfig.scripts.json && node --check packages/opencode-v2/src/plugin.mjs && node --check packages/opencode-v2/src/oauth-callback.mjs",
+    "test": "bun run --cwd packages/core build && bun test --isolate packages/core/src packages/opencode/src packages/pi/src test/ packages/opencode-v2/test/",
     "test:e2e": "bun test --isolate ./packages/e2e-tests/src/plugin-flow.e2e.test.ts ./packages/e2e-tests/src/cli-flow.e2e.test.ts ./packages/e2e-tests/src/rpc-tui-flow.e2e.test.ts ./packages/e2e-tests/src/fetch-guard.test.ts ./packages/e2e-tests/src/mock-antigravity-server.test.ts",
     "test:e2e:models": "bun run --cwd packages/opencode test:e2e:models",
     "test:e2e:regression": "bun run --cwd packages/opencode test:e2e:regression",

packages/opencode-v2/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/opencode-v2/README.md

@@ -0,0 +1,174 @@
+# opencode-v2-antigravity
+
+Google Antigravity provider for **OpenCode 2.x**, built on
+[`@cortexkit/antigravity-auth-core`](https://www.npmjs.com/package/@cortexkit/antigravity-auth-core).
+
+`@cortexkit/opencode-antigravity-auth` targets the OpenCode 1.x host
+(`engines.opencode: ">=1.17.13 <2"`): it patches `fetch()` and registers a TUI sidebar.
+OpenCode 2.x replaced that surface with a typed plugin API (`session.hook`,
+`integration.transform`, `tool.transform`, native provider packages), so the 1.x plugin cannot
+load there. This package is that missing host adapter — OAuth, transport, account pool, quota
+bookkeeping and the model registry all stay in the shared core.
+
+> **Terms-of-service warning.** This calls Antigravity's non-public internal API. It is not
+> endorsed by Google and may violate Google's Terms of Service; accounts have reportedly been
+> suspended for similar use. Use at your own risk and never with an important account.
+
+## Design
+
+```
+OpenCode 2.x                          this plugin                    Antigravity
+────────────                          ───────────                    ───────────
+native @opencode-ai/ai/providers/google
+  builds Gemini request  ──▶  session.hook("http.request")
+                                rewrites the URL to a 127.0.0.1 loopback
+                                       │
+                                       ▼
+                             loopback HTTP server
+                                · picks an account (hybrid strategy)
+                                · refreshes the OAuth token
+                                · ensureProjectContext()
+                                · agent envelope + labels/sessionId
+                                · fetchWithAgyCliTransport()  ──▶  daily-cloudcode-pa
+                                                                    (fallback cloudcode-pa)
+                                       │
+  parses Gemini SSE      ◀───────  unwrapped, schema-normalised SSE
+```
+
+Keeping the native `@opencode-ai/ai/providers/google` package as the codec means image, PDF and
+tool-call handling comes from the host instead of a hand-written adapter.
+
+Why a loopback server instead of returning a `Response` from the hook: OpenCode 2.x sends
+whatever `event.request` the hook leaves behind through its own HTTP client, and the
+`http.response` hook only runs after that request succeeded. A loopback endpoint keeps the
+core's raw HTTP/1.1 transport (agy header order, proxy support) while the host still sees a
+plain SSE response it can stream and cancel.
+
+## Install
+
+Install the adapter package itself (the shared core is pulled in automatically):
+
+```bash
+# once the package is published:
+npm install @cortexkit/opencode-v2-antigravity-auth
+# or from this repository (Bun workspace):
+bun install
+```
+
+The plugin entry is `src/plugin.mjs` inside the package. In `opencode.json`, point
+`plugins[].package` at that file — for an npm install use
+`node_modules/@cortexkit/opencode-v2-antigravity-auth/src/plugin.mjs` relative to the project,
+for a checkout use the absolute path
+`/path/to/antigravity-auth/packages/opencode-v2/src/plugin.mjs`. The example below uses a
+checkout path.
+
+Register the plugin and the models in `opencode.json` (full snippet in
+[`example/opencode.json`](example/opencode.json)):
+
+```jsonc
+{
+  "plugins": [
+    {
+      "package": "/absolute/path/to/antigravity-auth/packages/opencode-v2/src/plugin.mjs",
+      "options": {
+        // Optional: restrict which directories antigravity_read_document may read.
+        // Default: anything under the user's home directory (credential/secret
+        // paths are always blocked).
+        "readDocumentRoots": ["/absolute/path/to/project/docs"]
+      }
+    }
+  ],
+  "providers": {
+    "google": {
+      "models": {
+        "gemini-3.7-flash": {
+          "name": "Gemini 3.7 Flash",
+          "modelID": "gemini-3.7-flash",
+          "package": "@opencode-ai/ai/providers/google",
+          "capabilities": { "tools": true, "input": ["text", "image", "pdf"], "output": ["text"] },
+          "limit": { "context": 1048576, "output": 65536 },
+          "variants": [{ "id": "low" }, { "id": "medium" }, { "id": "high" }]
+        }
+      }
+    }
+  }
+}
+```
+
+## Accounts
+
+- Pool file: `antigravity-accounts.json` in the OpenCode config dir
+  (`$OPENCODE_CONFIG_DIR`, `$XDG_CONFIG_HOME/opencode`, `%APPDATA%\opencode`, or
+  `~/.config/opencode`); override with `ANTIGRAVITY_ACCOUNTS_FILE`. Storage schema v4 with the
+  core's fenced file lock, so the pool is shared with the 1.x plugin and the standalone CLI.
+- Add an account: connect the `google` integration and pick
+  **"Google Antigravity (add account)"**. Each login appends to the pool; existing accounts are
+  preserved. The callback listens on `127.0.0.1:51121/oauth-callback`.
+- Disable an account with `"enabled": false`.
+- Selection uses the core `hybrid` strategy. On `429`/`403` the account is cooled down and the
+  next one is tried, `401` forces a token refresh, and a bare `STOP` (empty candidates) is
+  retried up to three times.
+
+## Models
+
+| Selector | Variants | Wire model |
+| --- | --- | --- |
+| `google/gemini-3.7-flash` | low, medium, high | `gemini-3.7-flash-{tier}` |
+| `google/gemini-3.6-flash` | low, medium, high | `gemini-3.6-flash-{tier}` |
+| `google/gemini-3.5-flash` | low, medium, high | `gemini-3.5-flash-extra-low` / `gemini-3.5-flash-low` / `gemini-3-flash-agent` |
+| `google/gemini-3.1-pro` | low, high | `gemini-3.1-pro-low` / `gemini-pro-agent` |
+| `google/gemini-3.1-flash-image` | — | `gemini-3.1-flash-image` |
+| `google/claude-sonnet-4-6-thinking` | — | `claude-sonnet-4-6` |
+| `google/claude-opus-4-6-thinking` | — | `claude-opus-4-6-thinking` |
+| `google/gpt-oss-120b-medium` | — | `gpt-oss-120b-medium` |
+
+Model ids and tiers come from `resolveModelForHeaderStyle()`, so the registry stays the single
+source of truth.
+
+## Host quirks this plugin works around
+
+1. **GPT-OSS tool schemas** — the AGY GPT bridge re-encodes protobuf numeric constraints as
+   strings, so `minLength: 1` fails OpenAI JSON-Schema validation with `400 INVALID_ARGUMENT`.
+   Fixed by calling `normalizeGeminiTools(request, { moveNumericConstraintsToDescription: true })`
+   for `gpt-*` wire models.
+2. **Strict native event schema** — GPT-OSS opens a turn with `content` and no `parts`, and
+   Claude sometimes uses role `assistant`. Both are rejected by the native Gemini event schema
+   (`Invalid google/gemini stream event`), so every frame is normalised before being forwarded.
+3. **Response encoding** — the core transport already inflates gzip, so upstream
+   `content-encoding` headers must not be copied onto the loopback response.
+4. **PDF attachments** — the OpenCode 2.x CLI drops PDF attachments before the provider sees
+   them (the request arrives without any `inlineData`). The plugin therefore also registers an
+   `antigravity_read_document` tool that loads the file itself:
+   `antigravity_read_document({ path, question?, model? })` for `.pdf`, `.png`, `.jpg`, `.webp`,
+   `.gif`, `.heic`. Images attached in chat work without the tool.
+   **Security note:** the tool reads local files and sends them to the Antigravity server —
+   an untrusted PDF/image is a prompt-injection vector that could instruct the model to read
+   sensitive files. Paths are therefore checked: well-known credential/secret locations
+   (`~/.ssh`, `~/.config`, `~/.local`, `AppData`, `.env`, `*.key`, `*.pem`, `*.p12`, `*.pfx`,
+   `id_rsa`, `credentials`, `auth.json`, `antigravity-accounts.json`, …) are always refused,
+   and by default only files under the user's home directory are readable. To narrow the
+   readable root further, set the `readDocumentRoots` plugin option (array of absolute
+   directories). Prefer attaching documents in chat where the host preserves them.
+5. **Image output** — the native parser renders text and tool calls only, so generated images
+   are written to `<data dir>/antigravity-images/` and announced as text.
+
+## Logging and privacy
+
+`<state dir>/antigravity-v2.log` records routing, `#<account index>`, upstream status codes,
+rotation and saved image paths. No prompts, tokens, e-mail addresses or refresh tokens are
+written. Credentials live only in the pool file owned by the core.
+
+## Verified
+
+Windows 11, Node 24, OpenCode `0.0.0-beta-17595`, two-account pool:
+
+- all eight selectors above answered a live prompt, including every reasoning tier;
+- tool calling works end to end (the model called `read` and returned a directory listing);
+- PNG attachment recognised (a red square → "Red");
+- PDF read through `antigravity_read_document` (exact embedded string returned);
+- image generation produced two JPEG files on disk;
+- forced failover: disabling account `#0` routed the next request to account `#1`.
+
+## License
+
+MIT.