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

A memory-only config write mode exists, and nothing in this build turns it on

Not switched on
Useful2 Signal4
Internals Notable

Config can save to memory only, but nothing in this build enables that mode.

writersWithoutBackend: "memory" is accepted but passed by no code here.

Feature flag
tengu_hover_rest 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 v2.1.248: on

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 config layer can be put in a mode where saving global or project config returns without touching ~/.claude.json, keeping the change in memory only and logging a warning that it will be replaced the next time a real save or refresh rebuilds config. Entering the mode requires being handed writersWithoutBackend: "memory", which no code in this build passes, so it is reachable only from an embedder.

Details
  • Both call sites of the enable path pass only the storage backend and no options object, and the exported setter appears once, at its own definition, with no caller.
  • Doubly gated: the branch also needs the new storage backend, controlled by the tengu_hover_rest flag whose compiled fallback is off, overridable with the CLAUDE_CODE_HOVER_REST environment variable.
  • When it does fire, it emits a storage_v5_backend counter with reason unhanded_config_writer; deleting a project config has a matching in-memory branch.
Evidence

config: ${t} ran without the storage backend in a process whose config record has no file behind it; the change is in memory only and is replaced when a backend-handed save or refresh rebuilds the config from the record, unhanded_config_writer, ran without the storage backend in a process whose config record has no file behind it, writersWithoutBackend

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

See this entry in the whole of v2.1.248 →