Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.248 Home All releases olderv2.1.247 v2.1.250newer
Claude Code v2.1.248

One-hour prompt cache decision reworked around overage

Under the hood
Useful2 Signal3
Caching

Whether a one-hour prompt cache is allowed can now be overridden per agent and can ignore overage.

Feature flag
tengu_prompt_cache_1h_config Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.248: not a boolean we can read

Read once, for one account on one subscription tier, against v2.1.248. It isn't a statement about your account. What a flag value here can and cannot tell you

What

The code that decides whether a one-hour prompt cache lifetime is allowed now takes options, including an agent-level override and a flag to ignore cache overage, and computes overage once rather than per lookup.

Details
  • The allowlist of contexts permitted a one-hour cache comes from remote config, with a compiled fallback of repl_main_thread*, sdk, auto_mode and memdir_relevance.
Evidence

tengu_prompt_cache_1h_config

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Related

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

See this entry in the whole of v2.1.248 →