Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
Read ToolArea: what it touches
Internal ChangesKind: in v2.1.318,
Internal ChangesSection of the release
Unclear It is unclear when saved copies are set to be enveloped, so when users will see this framing is not known.
What
The Read tool is how Claude opens and reads files. Its results can now be wrapped in framing text that marks where the file's content starts and ends. This happens only when the framing setting for a saved copy of the file is enveloped.
If the file itself contains text that looks like those marker tags, Claude Code neutralizes it so it cannot be mistaken for the real start or end. The connection Claude Code uses to talk to remote sessions also gained a marker recording when a whole file was held back.
Why
This looks like protection against prompt injection, where text inside a file tries to pass itself off as instructions. The likely target is files synced from the cloud.
How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtIt is unclear when saved copies are set to be enveloped, so when users will see this framing is not known.
