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 v2.1.224 Home All releases olderv2.1.223 v2.1.225newer

Memory writes will require the version token from your last read

Not switched on
Useful3 Signal4
Memory

Memory writes will need the version token from your last read, forcing a read before overwriting.

The if_version requirement on memory writes sits behind a gate that defaults to false.

Feature flag
tengu_haze_glass Off in both readings

The flag server returned off for the account this site reads and for the anonymous baseline. A reading of off cannot rule out a rollout these two readings sit outside of.

This account: off · anonymous baseline: off · compiled default in v2.1.224: on

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.224. It isn't a statement about your account. What a flag value here can and cannot tell you

What

A build-gated change to the memory tools makes every write carry if_version: either the 12-character version token returned by the most recent read or write of that path, or the literal word new for a document that does not exist yet. The model therefore has to read a document before overwriting it. Reads now return the token; listing does not. Off in this build unless the tengu_haze_glass gate is on, which defaults to false.

Details
  • A stale token, or new against a path that already exists, rejects the write and returns the current content (when it fits within the read size cap) plus its current version, so the model can merge and retry.
  • Rejections are recorded as tengu_memory_tools_version_conflict with the reason.
Evidence

Every ${lS} needs if_version. Pass the literal word new for a document that does not yet exist.

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

See this entry in the whole of v2.1.224 →