Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.271 ·

Bidi-control-character check now table-driven

Detection of bidirectional-control text tricks now uses a lookup table instead of three hardcoded checks

TierUnder the hoodhow much it should matter to you
Useful1my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaPermissionswhat it touches
KindInternal Changesin v2.1.271,
Under the hood

Detection of bidirectional-control text tricks now uses a lookup table instead of three hardcoded checks

What

Claude Code's check for bidirectional control characters (invisible characters that can reorder how text displays, sometimes used to disguise malicious text) now loops through a table of character code ranges instead of testing three specific hardcoded conditions.

Why

This makes the detection easier to extend with new ranges going forward, without changing what a user experiences directly.

See this entry in the whole of v2.1.271 →