A Claude Code environment variable, read out of the shipped bundle.
It has been in the build since v2.1.138, including the newest one read.
Set to 1 to disable all built-in subagent types such as Explore and Plan. Only applies in non-interactive mode (the -p flag). Useful for SDK users who want a blank slate. This also removes general-purpose, the subagent Claude Code runs when an Agent tool call omits subagent_type. Such a call then fails with subagent_type is required
One resolver now picks no agents, coordinator or default, and the disable env var works as before.
named in this entry, found in this entry's text
First cited
1
The earliest release whose published evidence quoted CLAUDE_AGENT_SDK_DISABLE_BUILTIN_AGENTS was v2.1.232, 13 Aug 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.
ReleaseDateThe span that was quoted
v2.1.23213 Aug 2026CLAUDE_AGENT_SDK_DISABLE_BUILTIN_AGENTS
Presence across releases
1
BuildsHow manyDatesReading
v2.1.138 – v2.1.308149 builds9 May 2026 → 22 Oct 2026 ◆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.
v2.1.29914 Oct 2026·presentverdict: present · bool
v2.1.30014 Oct 2026·presentverdict: present · bool
v2.1.30115 Oct 2026·presentverdict: present · bool
v2.1.30216 Oct 2026·presentverdict: present · bool
v2.1.30318 Oct 2026·presentverdict: present · bool
v2.1.30419 Oct 2026·presentverdict: present · bool
v2.1.30520 Oct 2026·presentverdict: present · bool
v2.1.30621 Oct 2026·presentverdict: present · bool
v2.1.30721 Oct 2026·presentverdict: present · bool
v2.1.30822 Oct 2026·presentverdict: present · bool
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.
