---
name: feedback-cold-start-pump-duration
description: "cold_start_pump Duration param is io_timeout (per-IPC-call read deadline), NOT a connect timeout — misread this 3 times"
metadata: 
  node_type: memory
  type: feedback
  originSessionId: ef8120ee-5543-438f-98fe-b2ee24e79bce
---

`cold_start_pump(false, false, io_timeout_dur)` — the `Duration` arg is the **per-IPC-call read deadline**, not a connect timeout. Flakes manifest as `(false,false)` at ~2s when `request_attach`→`net_open_stream` journaled ack starves past the deadline under co-tenant load.

**Why:** Misread 3× during v0.13.0 hardening. The empirical proof: `=1` connect-Err print never fired; ack-timeout print confirmed 4/4 retries.

**How to apply:** When diagnosing cold_start_pump timeouts, check io_timeout starvation first, not connect failures. The env knob is `SPT_ATTACH_IPC_DEADLINE_MS` (default 2s production / 30000ms CI).