fix(antigravity): 429 RESOURCE_EXHAUSTED on consumer accounts due to hardcoded endpoint

Problem Description

When using the Antigravity provider in jcode (jcode --provider antigravity auth-test or running queries via jcode --provider antigravity -m <model>), requests immediately fail with:

HTTP 429 Too Many Requests: Resource has been exhausted (e.g. check quota).

However, the exact same Google account and models work seamlessly in the official Antigravity IDE at the same time.

Root Cause Analysis

1. Endpoint Discrepancy:

   • Inspecting the official Antigravity IDE language server arguments (ps aux | grep language_server) reveals that it connects to:

     --cloud_code_endpoint https://daily-cloudcode-pa.googleapis.com
     

   • In jcode, FETCH_MODELS_API_URL and GENERATE_CONTENT_API_URL were hardcoded to https://cloudcode-pa.googleapis.com.

2. GFE Host Routing:

   • Google Front End (GFE) routes requests based on the Host header.
   • For consumer accounts (@gmail.com allocated to project aicode-consumers), https://cloudcode-pa.googleapis.com rejects requests with:

     {
       "error": {
         "code": 429,
         "message": "Resource has been exhausted (e.g. check quota).",
         "status": "RESOURCE_EXHAUSTED"
       }
     }
     

   • Testing https://daily-cloudcode-pa.googleapis.com with the identical OAuth access token succeeds with HTTP 200 OK across all models (gemini-3.8-flash-tiered, gemini-3.7-flash-tiered, claude-opus-4-6-thinking, claude-sonnet-4-6).

---

Solution

Make the Antigravity endpoint configurable via an environment variable (JCODE_ANTIGRAVITY_ENDPOINT) while defaulting to https://daily-cloudcode-pa.googleapis.com, and add https://daily-cloudcode-pa.googleapis.com to LOAD_ENDPOINTS in jcode-base::auth::antigravity.

1. crates/jcode-provider-antigravity/src/lib.rs

pub const DEFAULT_ENDPOINT: &str = "https://daily-cloudcode-pa.googleapis.com";
pub const ENDPOINT_ENV: &str = "JCODE_ANTIGRAVITY_ENDPOINT";
pub const FETCH_MODELS_API_URL: &str =
    "https://daily-cloudcode-pa.googleapis.com/v1internal:fetchAvailableModels";
pub const GENERATE_CONTENT_API_URL: &str =
    "https://daily-cloudcode-pa.googleapis.com/v1internal:generateContent";

pub fn antigravity_endpoint() -> String {
    std::env::var(ENDPOINT_ENV)
        .ok()
        .map(|value| value.trim().trim_end_matches('/').to_string())
        .filter(|value| !value.is_empty())
        .unwrap_or_else(|| DEFAULT_ENDPOINT.to_string())
}

pub fn fetch_models_api_url() -> String {
    format!("{}/v1internal:fetchAvailableModels", antigravity_endpoint())
}

pub fn generate_content_api_url() -> String {
    format!("{}/v1internal:generateContent", antigravity_endpoint())
}

2. crates/jcode-base/src/provider/antigravity.rs

Use fetch_models_api_url() when querying available models:

let response = client
    .post(fetch_models_api_url())
    .header(reqwest::header::AUTHORIZATION, format!("Bearer {}", access_token))
    ...

3. crates/jcode-provider-antigravity-runtime/src/lib.rs

Use generate_content_api_url() when generating content:

let response = self
    .client
    .post(generate_content_api_url())
    .bearer_auth(&tokens.access_token)
    ...

4. crates/jcode-base/src/auth/antigravity.rs

Add https://daily-cloudcode-pa.googleapis.com to LOAD_ENDPOINTS:

const LOAD_ENDPOINTS: &[&str] = &[
    "https://daily-cloudcode-pa.googleapis.com",
    "https://cloudcode-pa.googleapis.com",
    "https://daily-cloudcode-pa.sandbox.googleapis.com",
    "https://autopush-cloudcode-pa.sandbox.googleapis.com",
];

---

Verification Results

After compiling with this patch:

1. jcode --provider antigravity auth-test:

   ✓ credential_probe — Loaded Antigravity OAuth tokens for vallabha717@gmail.com
   ✓ refresh_probe — Antigravity token load/refresh succeeded
   ✓ provider_smoke — Provider returned AUTH_TEST_OK.
   ✓ tool_smoke — Tool-enabled provider request returned AUTH_TEST_OK after one validated real Jcode bash tool call
   result: PASS
   

2. Real prompt tests succeeded with HTTP 200 on:
   • claude-opus-4-6-thinking
   • claude-sonnet-4-6
   • gemini-3.8-flash-tiered

Related to #1162.

Review the endpoint constants and request construction in crates/jcode-provider-antigravity/src/lib.rs, crates/jcode-base/src/provider/antigravity.rs, and crates/jcode-provider-antigravity-runtime/src/lib.rs, then inspect LOAD_ENDPOINTS in crates/jcode-base/src/auth/antigravity.rs. Run jcode --provider antigravity auth-test and verify that model discovery and content generation succeed for the daily endpoint while the endpoint remains configurable.