[chris7iu]

Summary

Adds an experimental, opt-in (default-off) native Antigravity provider (src/providers/antigravity/) for Anthropic /v1/messages and local /v1/messages/count_tokens backed directly by the Cloud Code Assist v1internal:streamGenerateContent?alt=sse API (no agy subprocess wrapper or credential import).

When disabled (the default), existing provider catalogs, model routing, aliases, and auto-review overrides are untouched.

Supported Models

• antigravity/gemini-4-carbon-{low,medium,high}
• antigravity/gemini-4-argon-{low,medium,high}
• antigravity/claude-opus-5-5-{low,medium,high}

(Optional [1m] model suffixes from Claude Code are accepted.)

Highlights

• Native wire protocol & streaming transport: Dedicated Hyper + rustls client defaulting to https://daily-cloudcode-pa.googleapis.com (baseUrl configurable), gzip response decoding, agy-aligned timeouts (300s header and SSE stream-idle budgets, 3600s turn deadline, no automatic inference retries), 15s downstream : ping\n\n SSE heartbeats while collecting buffered turns, and bounded/redacted upstream error diagnostics.
• Signed replay & mid-session /model switching: Preserves native parts and thought signatures in a versioned ccp:antigravity:v1: carrier across tool turns, canonicalizes client-normalized tool inputs, and folds unsigned or cross-model/cross-tier prefix turns into <prior_conversation_transcript> user context so mid-session model or effort changes continue cleanly.
• agy-style native Schema projection: Translates JSON Schema tool definitions directly into Cloud Code Assist v1main.Schema ($ref/$defs inlining with cycle guards, allOf/anyOf/oneOf normalization, const → enum, stringified enum values), skips Claude Code DeferredToolPlaceholder / defer_loading placeholders, and aliases MCP/external tool names outside [a-zA-Z_][a-zA-Z0-9_-]{0,63} via deterministic ccp_<sha256> mapping.
• Proxy-owned OAuth & singleflight refresh: Supports PKCE S256 loopback login (antigravity auth login), bounded foreground-TTY manual code entry on Unix (antigravity auth login --manual), logout, and pure read-only status / GET /v1/models?include_capabilities=true, with sibling-locked credential storage and singleflight token refresh.
• Effect-free token counting: /v1/messages/count_tokens estimates tokens locally without reading credentials, refreshing tokens, or making network calls.

Configuration & CLI

Enable via ~/.config/claude-code-proxy/config.json or CCP_ANTIGRAVITY_* environment variables:

{
  "antigravity": {
    "enabled": true,
    "clientId": "<oauth-client-id>",
    "clientSecret": "<oauth-client-secret>",
    "projectId": "<optional-gcp-project-id>",
    "baseUrl": "https://daily-cloudcode-pa.googleapis.com",
    "userAgent": "<optional-native-api-user-agent>"
  }
}

claude-code-proxy antigravity auth login [--manual]
claude-code-proxy antigravity auth status
claude-code-proxy antigravity auth logout

Test Plan

• cargo fmt --all -- --check
• cargo clippy --all-targets -- -D warnings
• cargo test --lib antigravity
• cargo test --test antigravity_schema_parity --test antigravity_transport --test server --test cli
• pytest tests/antigravity_compatibility