On a fresh boot with no resume_pending sessions, _finish_startup_restore
opened the inbound gate almost immediately while the agent-side turn
machinery (run_agent import graph, tool schemas + check_fn probes,
context-file tier) was still cold. A message arriving in that window was
served with a skeleton system prompt (~1.7K tokens vs ~14.6K healthy):
no AGENTS.md/context tier, no tool schemas, memory provider initializing
mid-turn.
Fix: start a background turn-machinery warm-up when the startup gate
closes (overlapping the network-bound platform connects) and have
_finish_startup_restore await it — BOUNDED by
agent.gateway_startup_warmup_timeout (default 20s, 0 disables) — before
draining the queue and opening the gate. On timeout the gate opens
anyway and the warm-up finishes in the background, so a wedged init can
never make the gateway permanently unavailable.
Reported by @yhfmstr in #99373.
Fixes#99373
Teknium
fc2421cfa7