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 v2.1.219 Home All releases olderv2.1.218 v2.1.220newer
Claude Code v2.1.219

Rewritten memory system prompt

Not switched on
Useful3 Signal3
Memory

Rewritten memory rules would make Claude save corrections and environment quirks immediately, before replying.

The new memory system prompt with must-save triggers is gated on tengu_stone_shell, which falls back to false.

Feature flag
tengu_stone_shell 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 v2.1.219: 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 v2.1.219. It isn't a statement about your account. What a flag value here can and cannot tell you

What

The memory instructions given to Claude were rewritten around three criteria and now specify when a memory must be written rather than leaving it to judgement.

Details
  • Criteria are applicable, durable, legible
  • Explicit MUST-save triggers: user corrections however phrased, skeptical questions, environment discoveries
  • New rule that memory writes happen before the reply that engages the correction, not after the conversation settles
  • The frontmatter template now includes a metadata: pinned: field
  • Gated on tengu_stone_shell, fallback false
Evidence

A good memory is applicable, durable, and legible

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

See this entry in the whole of v2.1.219 →