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Sweep 22 Oct 2026 · 21:04Z Build v2.1.309 528 read Stable v2.1.308 Latest v2.1.308 Next v2.1.309 Feeds RSS JSON llms.txt llms-full.txt Unofficial

Claude Code v2.1.219 ·

Rewritten memory system prompt

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

Nothing to try yet In Development
JSON All of v2.1.219
Nothing to try yetTier: how much it should matter to you
3Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
MemoryArea: what it touches
In DevelopmentKind: in v2.1.219,
In DevelopmentSection of the release

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

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.

Read from
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: off

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 has happened since
Flag reading moved The flag server now returns off for tengu_stone_shell, read as this account. A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
Flag reading moved The flag server now returns nothing at all, having stopped carrying it for tengu_stone_shell, read as this account. A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.

See this across every release →

See this entry in the whole of v2.1.219 →

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