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 v2.1.277 ·

Mermaid diagrams render as ASCII/box-drawing art in the terminal

Mermaid flowcharts and sequence diagrams in replies now render as text art in the terminal

TierYou'll noticehow much it should matter to you
Useful5my rating, 1 to 5
Signal4worth watching, 1 to 5
AreaTerminal Renderingwhat it touches
KindNew Featuresin v2.1.277,
You'll notice Notable

Mermaid flowcharts and sequence diagrams in replies now render as text art in the terminal

What

When an assistant reply includes a Mermaid diagram (a way of describing flowcharts and sequence diagrams as text, wrapped in a ```mermaid code block), Claude Code can now detect it and redraw it directly in the terminal using box-drawing characters, in place of the raw Mermaid source. If a diagram can't be laid out or is too large, it's left as plain text instead.

Why

This lets you see an actual diagram in the terminal instead of raw Mermaid markup, making flowcharts and sequence diagrams in a response easier to read at a glance. Whether this is active for a given account depends on a setting, tengu_mermaid_mod, which nothing has yet been read about.

Read from
Feature flag
tengu_mermaid_mod 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 v2.1.277: 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 v2.1.277. It isn't a statement about your account. What a flag value here can and cannot tell you

See this entry in the whole of v2.1.277 →