FULL STORY
Claude Code Subagent Cache: From Complaints to Real-World Tests
Developers complained that Claude Code's subagent prompt cache lasted only 5 minutes, driving up costs. Anthropic then extended it to 1 hour, and users tested whether the change actually saves money.
2026-10-10 ~ 2026-10-11 · 2 episodes · 6 posts
Episode 1 · Claude Code Subagent Cache Lasts Just 5 Minutes, Costing Users (2026-10-10, 4 posts)
Developer Daniel warns that Claude Code subagent prompt caches expire after just 5 minutes by default, silently inflating costs; a one-line config can extend the TTL to an hour. Anthropic's Boris Cherny explained the default reflects typical Agent SDK workloads.
- Claude Code subagent cache only lasts 5 minutes — one config tweak can save you money — daniel_mac8 · 2026-10-10
- Claude Code subagent cache expires after 5 minutes by default; set 1-hour TTL to cut costs — daniel_mac8 · 2026-10-10
- Claude Code subagent cache only lasts 5 minutes — set subagentPromptCacheTtl to avoid overpaying — daniel_mac8 · 2026-10-10
- Claude Code subagent cache lasts only 5 minutes; one config line keeps you from burning money — doodlestein · 2026-10-10
Episode 2 · Developer Tests Whether Extending Claude Code Subagent Cache to 1 Hour Saves Money (2026-10-11, 2 posts)
A developer released an open-source script to evaluate whether extending Claude Code's subagent prompt cache TTL from 5 minutes to 1 hour actually saves money, and after real-world testing reverted to the 5-minute default.
- Open-source script measures whether raising Claude Code subagent prompt cache TTL from 5m to 1h pays off — daniel_mac8 · 2026-10-11
- Claude Code tip: run this script to check if 1h subagent cache saves money — author's verdict was no — daniel_mac8 · 2026-10-11