CLAUDE_CODE_ENABLE_DESIGN_MCP
A Claude Code environment variable, read out of the shipped bundle. It was in the build from v2.1.179 and was gone by v2.1.206.
Forces the built-in Claude Design MCP server on (1, true, yes, on) or off (0, false, no, off); unset or any other value falls back to the tengu_omelette_whisk flag, default off. When on and the API provider is first-party, Claude Code adds an HTTP MCP server named claude_design at https://api.anthropic.com/v1/design/mcp to its built-in servers, and it also enables the /design command, which another condition can enable as well.
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.205 bundle, and it can be wrong.
In the changelogs
1Releases whose published page names CLAUDE_CODE_ENABLE_DESIGN_MCP.
-
v2.1.179
Claude Design MCP Integration [Gradual Rollout]
found in this entry's text
First cited
0No release's published evidence quotes this name. The ledger indexes the Evidence lines of every changelog on this site, so this says nobody here has ever quoted it; it says nothing about how old the name is.
Presence across releases
2Build by build
112One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the environment variable does. All environment variables.