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 v2.1.227 Home All releases olderv2.1.226 v2.1.228newer
Claude Code v2.1.227

Resuming an interrupted thinking block accepts more model spellings

Not switched on
Useful2 Signal3
Thinking

Resuming an interrupted thinking block now accepts model aliases, but the feature stays off.

Thinking-block resumption matches more model spellings but its flag defaults to false.

Feature flag
tengu_thinking_block_resumption 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 v2.1.227: 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 v2.1.227. It isn't a statement about your account. What a flag value here can and cannot tell you

What

The check that decides whether an interrupted thinking block can be resumed no longer demands an exact match against two model ids; it now compares canonical forms and a known alias set, so aliases of the same model qualify. Still off unless the tengu_thinking_block_resumption flag is enabled, which defaults to false.

Evidence

tengu_thinking_block_resumption

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 v2.1.227 →