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 v2.1.246 Home All releases olderv2.1.245 v2.1.247newer
Claude Code v2.1.246

Cloud sessions can pull a server-built memory context into the system prompt, off in this build

Not switched on
Useful2 Signal0
Memory

Cloud sessions can fetch a server-built memory block into the system prompt, off in this build.

Server-prepared memory context appended to the system prompt requires a remote entrypoint and tengu_misty_anchor, which falls back to false.

Feature flag
tengu_misty_anchor 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 v2.1.246: on

Read once, for one account on one subscription tier, against v2.1.246. It isn't a statement about your account. What a flag value here can and cannot tell you

What

New machinery lets a cloud session fetch a block of text prepared by the session host and append it to the system prompt before the conversation starts. It is off here: it requires a remote entrypoint, an auth check, and the tengu_misty_anchor flag, whose in-source fallback is false. Nothing in a normal local run fetches anything or changes the prompt.

Details
  • Fetches GET /memory_context from the session host with session-JWT auth, ETag revalidation via If-None-Match, a 10 second timeout and a 256KiB cap on the returned content.
  • The payload must be {version, content}; malformed responses are rejected.
  • Prompt assembly waits up to 2000ms for the fetch before assembling, then appends the content as an extra system-prompt block.
  • Handles 204 (no context), 304 (unchanged) and 429/503 (not built yet) distinctly.
  • Restricted to the remote_cowork, remote_cowork_trigger, remote_api and remote_trigger entrypoints.
  • Emits cowork_memory_context_fetched, _none, _not_built, _gated and _malformed.
  • None of this existed in 2.1.245.
Evidence

cowork_memory_context_fetched, cowork_memory_context_gated

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 v2.1.246 →