How to stop Claude Code from fetching feature flags with the CLAUDE_CODE_DISABLE_FEATURE_FLAGS environment variable

Starting with Claude Code 2.1.319, setting the CLAUDE_CODE_DISABLE_FEATURE_FLAGS environment variable stops feature-flag fetching. Telemetry stays on, and every flag runs on its built-in default.

1. Update Claude Code to 2.1.319 or later.

claude update

1. Set the variable and run Claude Code.

export CLAUDE_CODE_DISABLE_FEATURE_FLAGS=1
claude

The changelog gives only the variable name and its behavior, with no value format. 1 follows the other disable-style variables, and the environment variable docs don't list it yet.