- Configure upstream connection pool under antigravity.connection-pool with enabled: false by default.
- In short connection mode, set MaxIdleConnsPerHost = -1 with DisableKeepAlives = false, ensuring immediate TCP termination after response body completion without leaking Connection: close request headers.
- When pooling is explicitly enabled (enabled: true), cap idle-conn-timeout at 210s (leaving a 30s safety buffer below Google Frontend's 240s Keep-Alive cutoff) and default max-idle-conns-per-host to 2 (bounded at 100).
- Refactor TransportCache to execute CloseIdleConnections outside the mutex lock during LRU eviction and matching closes.
- Proactively evict and close idle connections on 429 quota exhaustion across Execute, ExecuteStream, and CountTokens.
- Wire hot-reload diff detection and server reload purge hooks for graceful transport pool updates.
Track when executor calls cross an upstream transport boundary and use that
signal to keep model/provider errors from being replaced by later local
preparation, selection, or internal failures.
Mark HTTP, websocket, relay, and usage-tracked transports as upstream
attempts, while avoiding marks for local validation, logging, missing
sessions, and successful websocket handshakes before request send.
Parse relative auth expiry metadata and adjust Antigravity refresh timing.
