CLAUDE_CODE_INVESTIGATE_FIRSTA Claude Code environment variable, read out of the shipped bundle.
It was in the build from v2.1.138 and was gone by v2.1.223.
Claude no longer spends up to a minute investigating before asking you a clarifying question.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.223 .
First seen v2.1.138 9 May 2026
Last seen v2.1.222 4 Aug 2026, gone by v2.1.223
Builds 75 / 149 on this box, as of v2.1.308
Written about v2.1.122 first named in a changelog, 28 Apr 2026
v2.1.138 v2.1.308
In the changelogs
2
Releases whose published page names CLAUDE_CODE_INVESTIGATE_FIRST.
v2.1.223 5 Aug 2026
v2.1.122 28 Apr 2026
First cited
1
The earliest release whose published evidence quoted CLAUDE_CODE_INVESTIGATE_FIRST was v2.1.122 , 28 Apr 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
Release Date The span that was quoted
v2.1.122 28 Apr 2026 CLAUDE_CODE_INVESTIGATE_FIRST
Presence across releases
2
Builds How many Dates Reading
v2.1.138 – v2.1.222 75 builds 9 May 2026 → 4 Aug 2026 ◆ in the build
v2.1.223 – v2.1.308 74 builds 5 Aug 2026 → 22 Oct 2026 ○ not in the build
Build by build
149
One 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.
Build Date State The record behind it
v2.1.138 9 May 2026 · presentverdict: present v2.1.139 11 May 2026 · presentverdict: present v2.1.140 12 May 2026 · presentverdict: present v2.1.163 4 Jun 2026 · presentverdict: present · bool v2.1.165 5 Jun 2026 · presentverdict: present · bool v2.1.166 5 Jun 2026 · presentverdict: present · bool v2.1.167 6 Jun 2026 · presentverdict: present · bool v2.1.168 6 Jun 2026 · presentverdict: present · bool v2.1.169 8 Jun 2026 · presentverdict: present · bool v2.1.170 9 Jun 2026 · presentverdict: present · bool v2.1.172 10 Jun 2026 · presentverdict: present · bool v2.1.173 11 Jun 2026 · presentverdict: present · bool v2.1.174 11 Jun 2026 · presentverdict: present · bool v2.1.175 12 Jun 2026 · presentverdict: present · bool v2.1.176 12 Jun 2026 · presentverdict: present · bool v2.1.177 13 Jun 2026 · presentverdict: present · bool v2.1.178 15 Jun 2026 · presentverdict: present · bool v2.1.179 16 Jun 2026 · presentverdict: present · bool v2.1.181 17 Jun 2026 · presentverdict: present · bool v2.1.182 18 Jun 2026 · presentverdict: present · bool v2.1.183 19 Jun 2026 · presentverdict: present · bool v2.1.185 20 Jun 2026 · presentverdict: present · bool v2.1.186 22 Jun 2026 · presentverdict: present · bool v2.1.187 23 Jun 2026 · presentverdict: present · bool v2.1.190 24 Jun 2026 · presentverdict: present · bool v2.1.191 24 Jun 2026 · presentverdict: present · bool v2.1.193 25 Jun 2026 · presentverdict: present · bool v2.1.195 26 Jun 2026 · presentverdict: present · bool v2.1.196 29 Jun 2026 · presentverdict: present · bool v2.1.197 30 Jun 2026 · presentverdict: present · bool v2.1.198 1 Jul 2026 · presentverdict: present · bool v2.1.199 2 Jul 2026 · presentverdict: present · bool v2.1.200 3 Jul 2026 · presentverdict: present · bool v2.1.201 3 Jul 2026 · presentverdict: present · bool v2.1.202 6 Jul 2026 · presentverdict: present · bool v2.1.203 7 Jul 2026 · presentverdict: present · bool v2.1.204 8 Jul 2026 · presentverdict: present · bool v2.1.205 8 Jul 2026 · presentverdict: present · bool v2.1.206 9 Jul 2026 · presentverdict: present · bool v2.1.207 10 Jul 2026 · presentverdict: present · bool v2.1.208 13 Jul 2026 · presentverdict: present · bool v2.1.209 14 Jul 2026 · presentverdict: present · bool v2.1.210 14 Jul 2026 · presentverdict: present · bool v2.1.211 15 Jul 2026 · presentverdict: present · bool v2.1.212 16 Jul 2026 · presentverdict: present · bool v2.1.213 17 Jul 2026 · presentverdict: present · bool v2.1.214 18 Jul 2026 · presentverdict: present · bool v2.1.215 19 Jul 2026 · presentverdict: present · bool v2.1.216 20 Jul 2026 · presentverdict: present · bool v2.1.217 21 Jul 2026 · presentverdict: present · bool v2.1.218 22 Jul 2026 · presentverdict: present · bool v2.1.219 24 Jul 2026 · presentverdict: present · bool v2.1.220 24 Jul 2026 · presentverdict: present · bool v2.1.221 3 Aug 2026 · presentverdict: present · bool v2.1.222 4 Aug 2026 · presentverdict: present · bool v2.1.223 5 Aug 2026 · removedverdict: removed
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 .
