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

Remote model list no longer overrides the simple system prompt

Use it now
Useful2 Signal3
System Prompt Notable not in their notes

Which models get the simple system prompt is now decided locally, not by remote config.

Feature flag
tengu_velvet_cascade 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 v2.1.227: not a boolean we can read

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.

tengu_velvet_tide 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

CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT
What

The tengu_velvet_cascade remote config, a JSON object listing models that should use the simple system prompt, is gone from the build. The choice now rests on the per-model capability entry, the CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT environment variable, and the existing tengu_velvet_tide escape hatch.

Evidence

tengu_velvet_cascade

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 →