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 v2.1.239 Home All releases olderv2.1.238 v2.1.240newer
Claude Code v2.1.239

Wider Unicode normalisation of untrusted text

You'll notice
Useful3 Signal3
Prompt Safety

Untrusted text is normalised harder, closing lookalike characters used to fake instruction markers.

What

Text coming from outside Claude Code is normalised more aggressively before it is inspected, closing off characters that could be used to disguise instruction markers. Combining accents are stripped, six more angle-bracket lookalikes are folded, and dash lookalikes and line/paragraph separators are now recognised as their plain equivalents.

Details
  • Combining marks are removed by decomposing the text and deleting all mark characters.
  • New homoglyphs mapped: \u226E, \u226F, \u227A, \u227B, \u22D6, \u22D7.
  • New character classes cover dash lookalikes such as the minus sign and super/subscript minus, and the control class now includes \u2028 and \u2029.
Evidence

e.normalize("NFKD").replace(/\p{M}+/gu, "")

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 v2.1.239 →