Codex on Bedrock can silently bill 2.5–10x: caching never fires

Bedrock users pay full price for a prefix cache that never gets read back; one config flag restores it — plus Codex 0.149 adds an agents dashboard.

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  • Cache writes every turn, reads near zero

    Routing Codex to Amazon Bedrock, it can't mark where its stable prompt prefix ends and rotates its cache key per session — so Bedrock rewrites the whole prefix every turn (cache writes bill at 1.25x input) and rarely reads it back. One analysis pegged the wasted writes at ~2.5x the corrected cost; an affected engineer reportedly saw them reach ~90% of GPT-5.6 spend.

  • The one-line fix: disable web search

    The developer who filed it found setting web_search = "disabled" dropped their bill roughly 10x, because injected search results kept breaking the reusable prefix on every call. Routing through a proxy that inserts the cache breakpoint and a stable key cut costs ~59% in the same writeup, and an open Codex issue tracks a native fix — still unshipped as of 0.149.

  • Elsewhere: Codex 0.149 adds an agents dashboard

    The Aug 20 Codex 0.149 release adds an interactive agents dashboard for juggling tasks, working-directory commands (/cd, /pwd, /cwd), queued messages you can stack on a running session, and expanded codex doctor diagnostics.